Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * postgres_fdw.c
4 : * Foreign-data wrapper for remote PostgreSQL servers
5 : *
6 : * Portions Copyright (c) 2012-2026, PostgreSQL Global Development Group
7 : *
8 : * IDENTIFICATION
9 : * contrib/postgres_fdw/postgres_fdw.c
10 : *
11 : *-------------------------------------------------------------------------
12 : */
13 : #include "postgres.h"
14 :
15 : #include <limits.h>
16 :
17 : #include "access/htup_details.h"
18 : #include "access/sysattr.h"
19 : #include "access/table.h"
20 : #include "catalog/pg_opfamily.h"
21 : #include "commands/defrem.h"
22 : #include "commands/explain_format.h"
23 : #include "commands/explain_state.h"
24 : #include "commands/vacuum.h"
25 : #include "executor/execAsync.h"
26 : #include "executor/instrument.h"
27 : #include "executor/spi.h"
28 : #include "foreign/fdwapi.h"
29 : #include "funcapi.h"
30 : #include "miscadmin.h"
31 : #include "nodes/makefuncs.h"
32 : #include "nodes/nodeFuncs.h"
33 : #include "optimizer/appendinfo.h"
34 : #include "optimizer/cost.h"
35 : #include "optimizer/inherit.h"
36 : #include "optimizer/optimizer.h"
37 : #include "optimizer/pathnode.h"
38 : #include "optimizer/paths.h"
39 : #include "optimizer/planmain.h"
40 : #include "optimizer/prep.h"
41 : #include "optimizer/restrictinfo.h"
42 : #include "optimizer/tlist.h"
43 : #include "parser/parsetree.h"
44 : #include "postgres_fdw.h"
45 : #include "statistics/statistics.h"
46 : #include "storage/latch.h"
47 : #include "utils/builtins.h"
48 : #include "utils/float.h"
49 : #include "utils/guc.h"
50 : #include "utils/lsyscache.h"
51 : #include "utils/memutils.h"
52 : #include "utils/rel.h"
53 : #include "utils/sampling.h"
54 : #include "utils/selfuncs.h"
55 :
56 30 : PG_MODULE_MAGIC_EXT(
57 : .name = "postgres_fdw",
58 : .version = PG_VERSION
59 : );
60 :
61 : /* Default CPU cost to start up a foreign query. */
62 : #define DEFAULT_FDW_STARTUP_COST 100.0
63 :
64 : /* Default CPU cost to process 1 row (above and beyond cpu_tuple_cost). */
65 : #define DEFAULT_FDW_TUPLE_COST 0.2
66 :
67 : /* If no remote estimates, assume a sort costs 20% extra */
68 : #define DEFAULT_FDW_SORT_MULTIPLIER 1.2
69 :
70 : /*
71 : * Indexes of FDW-private information stored in fdw_private lists.
72 : *
73 : * These items are indexed with the enum FdwScanPrivateIndex, so an item
74 : * can be fetched with list_nth(). For example, to get the SELECT statement:
75 : * sql = strVal(list_nth(fdw_private, FdwScanPrivateSelectSql));
76 : */
77 : enum FdwScanPrivateIndex
78 : {
79 : /* SQL statement to execute remotely (as a String node) */
80 : FdwScanPrivateSelectSql,
81 : /* Integer list of attribute numbers retrieved by the SELECT */
82 : FdwScanPrivateRetrievedAttrs,
83 : /* Integer representing the desired fetch_size */
84 : FdwScanPrivateFetchSize,
85 :
86 : /*
87 : * String describing join i.e. names of relations being joined and types
88 : * of join, added when the scan is join
89 : */
90 : FdwScanPrivateRelations,
91 : };
92 :
93 : /*
94 : * Similarly, this enum describes what's kept in the fdw_private list for
95 : * a ModifyTable node referencing a postgres_fdw foreign table. We store:
96 : *
97 : * 1) INSERT/UPDATE/DELETE statement text to be sent to the remote server
98 : * 2) Integer list of target attribute numbers for INSERT/UPDATE
99 : * (NIL for a DELETE)
100 : * 3) Length till the end of VALUES clause for INSERT
101 : * (-1 for a DELETE/UPDATE)
102 : * 4) Boolean flag showing if the remote query has a RETURNING clause
103 : * 5) Integer list of attribute numbers retrieved by RETURNING, if any
104 : */
105 : enum FdwModifyPrivateIndex
106 : {
107 : /* SQL statement to execute remotely (as a String node) */
108 : FdwModifyPrivateUpdateSql,
109 : /* Integer list of target attribute numbers for INSERT/UPDATE */
110 : FdwModifyPrivateTargetAttnums,
111 : /* Length till the end of VALUES clause (as an Integer node) */
112 : FdwModifyPrivateLen,
113 : /* has-returning flag (as a Boolean node) */
114 : FdwModifyPrivateHasReturning,
115 : /* Integer list of attribute numbers retrieved by RETURNING */
116 : FdwModifyPrivateRetrievedAttrs,
117 : };
118 :
119 : /*
120 : * Similarly, this enum describes what's kept in the fdw_private list for
121 : * a ForeignScan node that modifies a foreign table directly. We store:
122 : *
123 : * 1) UPDATE/DELETE statement text to be sent to the remote server
124 : * 2) Boolean flag showing if the remote query has a RETURNING clause
125 : * 3) Integer list of attribute numbers retrieved by RETURNING, if any
126 : * 4) Boolean flag showing if we set the command es_processed
127 : */
128 : enum FdwDirectModifyPrivateIndex
129 : {
130 : /* SQL statement to execute remotely (as a String node) */
131 : FdwDirectModifyPrivateUpdateSql,
132 : /* has-returning flag (as a Boolean node) */
133 : FdwDirectModifyPrivateHasReturning,
134 : /* Integer list of attribute numbers retrieved by RETURNING */
135 : FdwDirectModifyPrivateRetrievedAttrs,
136 : /* set-processed flag (as a Boolean node) */
137 : FdwDirectModifyPrivateSetProcessed,
138 : };
139 :
140 : /*
141 : * Execution state of a foreign scan using postgres_fdw.
142 : */
143 : typedef struct PgFdwScanState
144 : {
145 : Relation rel; /* relcache entry for the foreign table. NULL
146 : * for a foreign join scan. */
147 : TupleDesc tupdesc; /* tuple descriptor of scan */
148 : AttInMetadata *attinmeta; /* attribute datatype conversion metadata */
149 :
150 : /* extracted fdw_private data */
151 : char *query; /* text of SELECT command */
152 : List *retrieved_attrs; /* list of retrieved attribute numbers */
153 :
154 : /* for remote query execution */
155 : PGconn *conn; /* connection for the scan */
156 : PgFdwConnState *conn_state; /* extra per-connection state */
157 : unsigned int cursor_number; /* quasi-unique ID for my cursor */
158 : bool cursor_exists; /* have we created the cursor? */
159 : int numParams; /* number of parameters passed to query */
160 : FmgrInfo *param_flinfo; /* output conversion functions for them */
161 : List *param_exprs; /* executable expressions for param values */
162 : const char **param_values; /* textual values of query parameters */
163 :
164 : /* for storing result tuples */
165 : HeapTuple *tuples; /* array of currently-retrieved tuples */
166 : int num_tuples; /* # of tuples in array */
167 : int next_tuple; /* index of next one to return */
168 :
169 : /* batch-level state, for optimizing rewinds and avoiding useless fetch */
170 : int fetch_ct_2; /* Min(# of fetches done, 2) */
171 : bool eof_reached; /* true if last fetch reached EOF */
172 :
173 : /* for asynchronous execution */
174 : bool async_capable; /* engage asynchronous-capable logic? */
175 :
176 : /* working memory contexts */
177 : MemoryContext batch_cxt; /* context holding current batch of tuples */
178 : MemoryContext temp_cxt; /* context for per-tuple temporary data */
179 :
180 : int fetch_size; /* number of tuples per fetch */
181 : } PgFdwScanState;
182 :
183 : /*
184 : * Execution state of a foreign insert/update/delete operation.
185 : */
186 : typedef struct PgFdwModifyState
187 : {
188 : Relation rel; /* relcache entry for the foreign table */
189 : AttInMetadata *attinmeta; /* attribute datatype conversion metadata */
190 :
191 : /* for remote query execution */
192 : PGconn *conn; /* connection for the scan */
193 : PgFdwConnState *conn_state; /* extra per-connection state */
194 : char *p_name; /* name of prepared statement, if created */
195 :
196 : /* extracted fdw_private data */
197 : char *query; /* text of INSERT/UPDATE/DELETE command */
198 : char *orig_query; /* original text of INSERT command */
199 : List *target_attrs; /* list of target attribute numbers */
200 : int values_end; /* length up to the end of VALUES */
201 : int batch_size; /* value of FDW option "batch_size" */
202 : bool has_returning; /* is there a RETURNING clause? */
203 : List *retrieved_attrs; /* attr numbers retrieved by RETURNING */
204 :
205 : /* info about parameters for prepared statement */
206 : AttrNumber ctidAttno; /* attnum of input resjunk ctid column */
207 : int p_nums; /* number of parameters to transmit */
208 : FmgrInfo *p_flinfo; /* output conversion functions for them */
209 :
210 : /* batch operation stuff */
211 : int num_slots; /* number of slots to insert */
212 :
213 : /* working memory context */
214 : MemoryContext temp_cxt; /* context for per-tuple temporary data */
215 :
216 : /* for update row movement if subplan result rel */
217 : struct PgFdwModifyState *aux_fmstate; /* foreign-insert state, if
218 : * created */
219 : } PgFdwModifyState;
220 :
221 : /*
222 : * Execution state of a foreign scan that modifies a foreign table directly.
223 : */
224 : typedef struct PgFdwDirectModifyState
225 : {
226 : Relation rel; /* relcache entry for the foreign table */
227 : AttInMetadata *attinmeta; /* attribute datatype conversion metadata */
228 :
229 : /* extracted fdw_private data */
230 : char *query; /* text of UPDATE/DELETE command */
231 : bool has_returning; /* is there a RETURNING clause? */
232 : List *retrieved_attrs; /* attr numbers retrieved by RETURNING */
233 : bool set_processed; /* do we set the command es_processed? */
234 :
235 : /* for remote query execution */
236 : PGconn *conn; /* connection for the update */
237 : PgFdwConnState *conn_state; /* extra per-connection state */
238 : int numParams; /* number of parameters passed to query */
239 : FmgrInfo *param_flinfo; /* output conversion functions for them */
240 : List *param_exprs; /* executable expressions for param values */
241 : const char **param_values; /* textual values of query parameters */
242 :
243 : /* for storing result tuples */
244 : PGresult *result; /* result for query */
245 : int num_tuples; /* # of result tuples */
246 : int next_tuple; /* index of next one to return */
247 : Relation resultRel; /* relcache entry for the target relation */
248 : AttrNumber *attnoMap; /* array of attnums of input user columns */
249 : AttrNumber ctidAttno; /* attnum of input ctid column */
250 : AttrNumber oidAttno; /* attnum of input oid column */
251 : bool hasSystemCols; /* are there system columns of resultRel? */
252 :
253 : /* working memory context */
254 : MemoryContext temp_cxt; /* context for per-tuple temporary data */
255 : } PgFdwDirectModifyState;
256 :
257 : /*
258 : * Workspace for analyzing a foreign table.
259 : */
260 : typedef struct PgFdwAnalyzeState
261 : {
262 : Relation rel; /* relcache entry for the foreign table */
263 : AttInMetadata *attinmeta; /* attribute datatype conversion metadata */
264 : List *retrieved_attrs; /* attr numbers retrieved by query */
265 :
266 : /* collected sample rows */
267 : HeapTuple *rows; /* array of size targrows */
268 : int targrows; /* target # of sample rows */
269 : int numrows; /* # of sample rows collected */
270 :
271 : /* for random sampling */
272 : double samplerows; /* # of rows fetched */
273 : double rowstoskip; /* # of rows to skip before next sample */
274 : ReservoirStateData rstate; /* state for reservoir sampling */
275 :
276 : /* working memory contexts */
277 : MemoryContext anl_cxt; /* context for per-analyze lifespan data */
278 : MemoryContext temp_cxt; /* context for per-tuple temporary data */
279 : } PgFdwAnalyzeState;
280 :
281 : /*
282 : * This enum describes what's kept in the fdw_private list for a ForeignPath.
283 : * We store:
284 : *
285 : * 1) Boolean flag showing if the remote query has the final sort
286 : * 2) Boolean flag showing if the remote query has the LIMIT clause
287 : */
288 : enum FdwPathPrivateIndex
289 : {
290 : /* has-final-sort flag (as a Boolean node) */
291 : FdwPathPrivateHasFinalSort,
292 : /* has-limit flag (as a Boolean node) */
293 : FdwPathPrivateHasLimit,
294 : };
295 :
296 : /* Struct for extra information passed to estimate_path_cost_size() */
297 : typedef struct
298 : {
299 : PathTarget *target;
300 : bool has_final_sort;
301 : bool has_limit;
302 : double limit_tuples;
303 : int64 count_est;
304 : int64 offset_est;
305 : } PgFdwPathExtraData;
306 :
307 : /*
308 : * Identify the attribute where data conversion fails.
309 : */
310 : typedef struct ConversionLocation
311 : {
312 : AttrNumber cur_attno; /* attribute number being processed, or 0 */
313 : Relation rel; /* foreign table being processed, or NULL */
314 : ForeignScanState *fsstate; /* plan node being processed, or NULL */
315 : } ConversionLocation;
316 :
317 : /* Callback argument for ec_member_matches_foreign */
318 : typedef struct
319 : {
320 : Expr *current; /* current expr, or NULL if not yet found */
321 : List *already_used; /* expressions already dealt with */
322 : } ec_member_foreign_arg;
323 :
324 : /* Pairs of remote columns with local columns */
325 : typedef struct
326 : {
327 : AttrNumber local_attnum;
328 : char local_attname[NAMEDATALEN];
329 : char remote_attname[NAMEDATALEN];
330 : int res_index;
331 : } RemoteAttributeMapping;
332 :
333 : /* Result sets that are returned from a foreign statistics scan */
334 : typedef struct
335 : {
336 : PGresult *rel;
337 : PGresult *att;
338 : int server_version_num;
339 : } RemoteStatsResults;
340 :
341 : /* Column order in relation stats query */
342 : enum RelStatsColumns
343 : {
344 : RELSTATS_RELPAGES = 0,
345 : RELSTATS_RELTUPLES,
346 : RELSTATS_RELKIND,
347 : RELSTATS_NUM_FIELDS,
348 : };
349 :
350 : /* Column order in attribute stats query */
351 : enum AttStatsColumns
352 : {
353 : ATTSTATS_ATTNAME = 0,
354 : ATTSTATS_NULL_FRAC,
355 : ATTSTATS_AVG_WIDTH,
356 : ATTSTATS_N_DISTINCT,
357 : ATTSTATS_MOST_COMMON_VALS,
358 : ATTSTATS_MOST_COMMON_FREQS,
359 : ATTSTATS_HISTOGRAM_BOUNDS,
360 : ATTSTATS_CORRELATION,
361 : ATTSTATS_MOST_COMMON_ELEMS,
362 : ATTSTATS_MOST_COMMON_ELEM_FREQS,
363 : ATTSTATS_ELEM_COUNT_HISTOGRAM,
364 : ATTSTATS_RANGE_LENGTH_HISTOGRAM,
365 : ATTSTATS_RANGE_EMPTY_FRAC,
366 : ATTSTATS_RANGE_BOUNDS_HISTOGRAM,
367 : ATTSTATS_NUM_FIELDS,
368 : };
369 :
370 : /* Relation stats import query */
371 : static const char *relimport_sql =
372 : "SELECT pg_catalog.pg_restore_relation_stats(\n"
373 : "\t'version', $1,\n"
374 : "\t'schemaname', $2,\n"
375 : "\t'relname', $3,\n"
376 : "\t'relpages', $4::integer,\n"
377 : "\t'reltuples', $5::real)";
378 :
379 : /* Argument order in relation stats import query */
380 : enum RelImportSqlArgs
381 : {
382 : RELIMPORT_SQL_VERSION = 0,
383 : RELIMPORT_SQL_SCHEMANAME,
384 : RELIMPORT_SQL_RELNAME,
385 : RELIMPORT_SQL_RELPAGES,
386 : RELIMPORT_SQL_RELTUPLES,
387 : RELIMPORT_SQL_NUM_FIELDS
388 : };
389 :
390 : /* Argument types in relation stats import query */
391 : static const Oid relimport_argtypes[RELIMPORT_SQL_NUM_FIELDS] =
392 : {
393 : INT4OID, TEXTOID, TEXTOID, TEXTOID,
394 : TEXTOID,
395 : };
396 :
397 : /* Attribute stats import query */
398 : static const char *attimport_sql =
399 : "SELECT pg_catalog.pg_restore_attribute_stats(\n"
400 : "\t'version', $1,\n"
401 : "\t'schemaname', $2,\n"
402 : "\t'relname', $3,\n"
403 : "\t'attnum', $4,\n"
404 : "\t'inherited', false::boolean,\n"
405 : "\t'null_frac', $5::real,\n"
406 : "\t'avg_width', $6::integer,\n"
407 : "\t'n_distinct', $7::real,\n"
408 : "\t'most_common_vals', $8,\n"
409 : "\t'most_common_freqs', $9::real[],\n"
410 : "\t'histogram_bounds', $10,\n"
411 : "\t'correlation', $11::real,\n"
412 : "\t'most_common_elems', $12,\n"
413 : "\t'most_common_elem_freqs', $13::real[],\n"
414 : "\t'elem_count_histogram', $14::real[],\n"
415 : "\t'range_length_histogram', $15,\n"
416 : "\t'range_empty_frac', $16::real,\n"
417 : "\t'range_bounds_histogram', $17)";
418 :
419 : /* Argument order in attribute stats import query */
420 : enum AttImportSqlArgs
421 : {
422 : ATTIMPORT_SQL_VERSION = 0,
423 : ATTIMPORT_SQL_SCHEMANAME,
424 : ATTIMPORT_SQL_RELNAME,
425 : ATTIMPORT_SQL_ATTNUM,
426 : ATTIMPORT_SQL_NULL_FRAC,
427 : ATTIMPORT_SQL_AVG_WIDTH,
428 : ATTIMPORT_SQL_N_DISTINCT,
429 : ATTIMPORT_SQL_MOST_COMMON_VALS,
430 : ATTIMPORT_SQL_MOST_COMMON_FREQS,
431 : ATTIMPORT_SQL_HISTOGRAM_BOUNDS,
432 : ATTIMPORT_SQL_CORRELATION,
433 : ATTIMPORT_SQL_MOST_COMMON_ELEMS,
434 : ATTIMPORT_SQL_MOST_COMMON_ELEM_FREQS,
435 : ATTIMPORT_SQL_ELEM_COUNT_HISTOGRAM,
436 : ATTIMPORT_SQL_RANGE_LENGTH_HISTOGRAM,
437 : ATTIMPORT_SQL_RANGE_EMPTY_FRAC,
438 : ATTIMPORT_SQL_RANGE_BOUNDS_HISTOGRAM,
439 : ATTIMPORT_SQL_NUM_FIELDS
440 : };
441 :
442 : /* Argument types in attribute stats import query */
443 : static const Oid attimport_argtypes[ATTIMPORT_SQL_NUM_FIELDS] =
444 : {
445 : INT4OID, TEXTOID, TEXTOID, INT2OID,
446 : TEXTOID, TEXTOID, TEXTOID, TEXTOID,
447 : TEXTOID, TEXTOID, TEXTOID, TEXTOID,
448 : TEXTOID, TEXTOID, TEXTOID, TEXTOID,
449 : TEXTOID,
450 : };
451 :
452 : /*
453 : * The mapping of attribute stats query columns to the positional arguments in
454 : * the prepared pg_restore_attribute_stats() statement.
455 : */
456 : typedef struct
457 : {
458 : enum AttStatsColumns res_field;
459 : enum AttImportSqlArgs arg_num;
460 : } AttrResultArgMap;
461 :
462 : #define NUM_MAPPED_ATTIMPORT_ARGS 13
463 :
464 : static const AttrResultArgMap attr_result_arg_map[NUM_MAPPED_ATTIMPORT_ARGS] =
465 : {
466 : {ATTSTATS_NULL_FRAC, ATTIMPORT_SQL_NULL_FRAC},
467 : {ATTSTATS_AVG_WIDTH, ATTIMPORT_SQL_AVG_WIDTH},
468 : {ATTSTATS_N_DISTINCT, ATTIMPORT_SQL_N_DISTINCT},
469 : {ATTSTATS_MOST_COMMON_VALS, ATTIMPORT_SQL_MOST_COMMON_VALS},
470 : {ATTSTATS_MOST_COMMON_FREQS, ATTIMPORT_SQL_MOST_COMMON_FREQS},
471 : {ATTSTATS_HISTOGRAM_BOUNDS, ATTIMPORT_SQL_HISTOGRAM_BOUNDS},
472 : {ATTSTATS_CORRELATION, ATTIMPORT_SQL_CORRELATION},
473 : {ATTSTATS_MOST_COMMON_ELEMS, ATTIMPORT_SQL_MOST_COMMON_ELEMS},
474 : {ATTSTATS_MOST_COMMON_ELEM_FREQS, ATTIMPORT_SQL_MOST_COMMON_ELEM_FREQS},
475 : {ATTSTATS_ELEM_COUNT_HISTOGRAM, ATTIMPORT_SQL_ELEM_COUNT_HISTOGRAM},
476 : {ATTSTATS_RANGE_LENGTH_HISTOGRAM, ATTIMPORT_SQL_RANGE_LENGTH_HISTOGRAM},
477 : {ATTSTATS_RANGE_EMPTY_FRAC, ATTIMPORT_SQL_RANGE_EMPTY_FRAC},
478 : {ATTSTATS_RANGE_BOUNDS_HISTOGRAM, ATTIMPORT_SQL_RANGE_BOUNDS_HISTOGRAM},
479 : };
480 :
481 : /* Attribute stats clear query */
482 : static const char *attclear_sql =
483 : "SELECT pg_catalog.pg_clear_attribute_stats($1, $2, $3, false)";
484 :
485 : /* Argument order in attribute stats clear query */
486 : enum AttClearSqlArgs
487 : {
488 : ATTCLEAR_SQL_SCHEMANAME = 0,
489 : ATTCLEAR_SQL_RELNAME,
490 : ATTCLEAR_SQL_ATTNAME,
491 : ATTCLEAR_SQL_NUM_FIELDS
492 : };
493 :
494 : /* Argument types in attribute stats clear query */
495 : static const Oid attclear_argtypes[ATTCLEAR_SQL_NUM_FIELDS] =
496 : {
497 : TEXTOID, TEXTOID, TEXTOID,
498 : };
499 :
500 : /*
501 : * SQL functions
502 : */
503 16 : PG_FUNCTION_INFO_V1(postgres_fdw_handler);
504 :
505 : /*
506 : * FDW callback routines
507 : */
508 : static void postgresGetForeignRelSize(PlannerInfo *root,
509 : RelOptInfo *baserel,
510 : Oid foreigntableid);
511 : static void postgresGetForeignPaths(PlannerInfo *root,
512 : RelOptInfo *baserel,
513 : Oid foreigntableid);
514 : static ForeignScan *postgresGetForeignPlan(PlannerInfo *root,
515 : RelOptInfo *foreignrel,
516 : Oid foreigntableid,
517 : ForeignPath *best_path,
518 : List *tlist,
519 : List *scan_clauses,
520 : Plan *outer_plan);
521 : static void postgresBeginForeignScan(ForeignScanState *node, int eflags);
522 : static TupleTableSlot *postgresIterateForeignScan(ForeignScanState *node);
523 : static void postgresReScanForeignScan(ForeignScanState *node);
524 : static void postgresEndForeignScan(ForeignScanState *node);
525 : static void postgresAddForeignUpdateTargets(PlannerInfo *root,
526 : Index rtindex,
527 : RangeTblEntry *target_rte,
528 : Relation target_relation);
529 : static List *postgresPlanForeignModify(PlannerInfo *root,
530 : ModifyTable *plan,
531 : Index resultRelation,
532 : int subplan_index);
533 : static void postgresBeginForeignModify(ModifyTableState *mtstate,
534 : ResultRelInfo *resultRelInfo,
535 : List *fdw_private,
536 : int subplan_index,
537 : int eflags);
538 : static TupleTableSlot *postgresExecForeignInsert(EState *estate,
539 : ResultRelInfo *resultRelInfo,
540 : TupleTableSlot *slot,
541 : TupleTableSlot *planSlot);
542 : static TupleTableSlot **postgresExecForeignBatchInsert(EState *estate,
543 : ResultRelInfo *resultRelInfo,
544 : TupleTableSlot **slots,
545 : TupleTableSlot **planSlots,
546 : int *numSlots);
547 : static int postgresGetForeignModifyBatchSize(ResultRelInfo *resultRelInfo);
548 : static TupleTableSlot *postgresExecForeignUpdate(EState *estate,
549 : ResultRelInfo *resultRelInfo,
550 : TupleTableSlot *slot,
551 : TupleTableSlot *planSlot);
552 : static TupleTableSlot *postgresExecForeignDelete(EState *estate,
553 : ResultRelInfo *resultRelInfo,
554 : TupleTableSlot *slot,
555 : TupleTableSlot *planSlot);
556 : static void postgresEndForeignModify(EState *estate,
557 : ResultRelInfo *resultRelInfo);
558 : static void postgresBeginForeignInsert(ModifyTableState *mtstate,
559 : ResultRelInfo *resultRelInfo);
560 : static void postgresEndForeignInsert(EState *estate,
561 : ResultRelInfo *resultRelInfo);
562 : static int postgresIsForeignRelUpdatable(Relation rel);
563 : static bool postgresPlanDirectModify(PlannerInfo *root,
564 : ModifyTable *plan,
565 : Index resultRelation,
566 : int subplan_index);
567 : static void postgresBeginDirectModify(ForeignScanState *node, int eflags);
568 : static TupleTableSlot *postgresIterateDirectModify(ForeignScanState *node);
569 : static void postgresEndDirectModify(ForeignScanState *node);
570 : static void postgresExplainForeignScan(ForeignScanState *node,
571 : ExplainState *es);
572 : static void postgresExplainForeignModify(ModifyTableState *mtstate,
573 : ResultRelInfo *rinfo,
574 : List *fdw_private,
575 : int subplan_index,
576 : ExplainState *es);
577 : static void postgresExplainDirectModify(ForeignScanState *node,
578 : ExplainState *es);
579 : static void postgresExecForeignTruncate(List *rels,
580 : DropBehavior behavior,
581 : bool restart_seqs);
582 : static bool postgresAnalyzeForeignTable(Relation relation,
583 : AcquireSampleRowsFunc *func,
584 : BlockNumber *totalpages);
585 : static bool postgresImportForeignStatistics(Relation relation,
586 : List *va_cols,
587 : int elevel);
588 : static List *postgresImportForeignSchema(ImportForeignSchemaStmt *stmt,
589 : Oid serverOid);
590 : static void postgresGetForeignJoinPaths(PlannerInfo *root,
591 : RelOptInfo *joinrel,
592 : RelOptInfo *outerrel,
593 : RelOptInfo *innerrel,
594 : JoinType jointype,
595 : JoinPathExtraData *extra);
596 : static bool postgresRecheckForeignScan(ForeignScanState *node,
597 : TupleTableSlot *slot);
598 : static void postgresGetForeignUpperPaths(PlannerInfo *root,
599 : UpperRelationKind stage,
600 : RelOptInfo *input_rel,
601 : RelOptInfo *output_rel,
602 : void *extra);
603 : static bool postgresIsForeignPathAsyncCapable(ForeignPath *path);
604 : static void postgresForeignAsyncRequest(AsyncRequest *areq);
605 : static void postgresForeignAsyncConfigureWait(AsyncRequest *areq);
606 : static void postgresForeignAsyncNotify(AsyncRequest *areq);
607 :
608 : /*
609 : * Helper functions
610 : */
611 : static void estimate_path_cost_size(PlannerInfo *root,
612 : RelOptInfo *foreignrel,
613 : List *param_join_conds,
614 : List *pathkeys,
615 : PgFdwPathExtraData *fpextra,
616 : double *p_rows, int *p_width,
617 : int *p_disabled_nodes,
618 : Cost *p_startup_cost, Cost *p_total_cost);
619 : static void get_remote_estimate(const char *sql,
620 : PGconn *conn,
621 : double *rows,
622 : int *width,
623 : Cost *startup_cost,
624 : Cost *total_cost);
625 : static void adjust_foreign_grouping_path_cost(PlannerInfo *root,
626 : List *pathkeys,
627 : double retrieved_rows,
628 : double width,
629 : double limit_tuples,
630 : int *p_disabled_nodes,
631 : Cost *p_startup_cost,
632 : Cost *p_run_cost);
633 : static bool ec_member_matches_foreign(PlannerInfo *root, RelOptInfo *rel,
634 : EquivalenceClass *ec, EquivalenceMember *em,
635 : void *arg);
636 : static void create_cursor(ForeignScanState *node);
637 : static void fetch_more_data(ForeignScanState *node);
638 : static void close_cursor(PGconn *conn, unsigned int cursor_number,
639 : PgFdwConnState *conn_state);
640 : static PgFdwModifyState *create_foreign_modify(EState *estate,
641 : RangeTblEntry *rte,
642 : ResultRelInfo *resultRelInfo,
643 : CmdType operation,
644 : Plan *subplan,
645 : char *query,
646 : List *target_attrs,
647 : int values_end,
648 : bool has_returning,
649 : List *retrieved_attrs);
650 : static TupleTableSlot **execute_foreign_modify(EState *estate,
651 : ResultRelInfo *resultRelInfo,
652 : CmdType operation,
653 : TupleTableSlot **slots,
654 : TupleTableSlot **planSlots,
655 : int *numSlots);
656 : static void prepare_foreign_modify(PgFdwModifyState *fmstate);
657 : static const char **convert_prep_stmt_params(PgFdwModifyState *fmstate,
658 : ItemPointer tupleid,
659 : TupleTableSlot **slots,
660 : int numSlots);
661 : static void store_returning_result(PgFdwModifyState *fmstate,
662 : TupleTableSlot *slot, PGresult *res);
663 : static void finish_foreign_modify(PgFdwModifyState *fmstate);
664 : static void deallocate_query(PgFdwModifyState *fmstate);
665 : static List *build_remote_returning(Index rtindex, Relation rel,
666 : List *returningList);
667 : static void rebuild_fdw_scan_tlist(ForeignScan *fscan, List *tlist);
668 : static void execute_dml_stmt(ForeignScanState *node);
669 : static TupleTableSlot *get_returning_data(ForeignScanState *node);
670 : static void init_returning_filter(PgFdwDirectModifyState *dmstate,
671 : List *fdw_scan_tlist,
672 : Index rtindex);
673 : static TupleTableSlot *apply_returning_filter(PgFdwDirectModifyState *dmstate,
674 : ResultRelInfo *resultRelInfo,
675 : TupleTableSlot *slot,
676 : EState *estate);
677 : static void prepare_query_params(PlanState *node,
678 : List *fdw_exprs,
679 : int numParams,
680 : FmgrInfo **param_flinfo,
681 : List **param_exprs,
682 : const char ***param_values);
683 : static void process_query_params(ExprContext *econtext,
684 : FmgrInfo *param_flinfo,
685 : List *param_exprs,
686 : const char **param_values);
687 : static int postgresAcquireSampleRowsFunc(Relation relation, int elevel,
688 : HeapTuple *rows, int targrows,
689 : double *totalrows,
690 : double *totaldeadrows);
691 : static void analyze_row_processor(PGresult *res, int row,
692 : PgFdwAnalyzeState *astate);
693 : static bool fetch_remote_statistics(Relation relation,
694 : List *va_cols,
695 : ForeignTable *table,
696 : const char *local_schemaname,
697 : const char *local_relname,
698 : int *p_attrcnt,
699 : RemoteAttributeMapping **p_remattrmap,
700 : RemoteStatsResults *remstats);
701 : static PGresult *fetch_relstats(PGconn *conn, Relation relation);
702 : static PGresult *fetch_attstats(PGconn *conn, int server_version_num,
703 : const char *remote_schemaname, const char *remote_relname,
704 : const char *column_list);
705 : static RemoteAttributeMapping *build_remattrmap(Relation relation, List *va_cols,
706 : int *p_attrcnt, StringInfo column_list);
707 : static bool attname_in_list(const char *attname, List *va_cols);
708 : static int remattrmap_cmp(const void *v1, const void *v2);
709 : static bool match_attrmap(PGresult *res,
710 : const char *local_schemaname,
711 : const char *local_relname,
712 : const char *remote_schemaname,
713 : const char *remote_relname,
714 : int attrcnt,
715 : RemoteAttributeMapping *remattrmap);
716 : static bool import_fetched_statistics(const char *schemaname,
717 : const char *relname,
718 : int attrcnt,
719 : const RemoteAttributeMapping *remattrmap,
720 : RemoteStatsResults *remstats);
721 : static void map_field_to_arg(PGresult *res, int row, int field,
722 : int arg, Datum *values, char *nulls);
723 : static bool import_spi_query_ok(void);
724 : static void produce_tuple_asynchronously(AsyncRequest *areq, bool fetch);
725 : static void fetch_more_data_begin(AsyncRequest *areq);
726 : static void complete_pending_request(AsyncRequest *areq);
727 : static HeapTuple make_tuple_from_result_row(PGresult *res,
728 : int row,
729 : Relation rel,
730 : AttInMetadata *attinmeta,
731 : List *retrieved_attrs,
732 : ForeignScanState *fsstate,
733 : MemoryContext temp_context);
734 : static void conversion_error_callback(void *arg);
735 : static bool foreign_join_ok(PlannerInfo *root, RelOptInfo *joinrel,
736 : JoinType jointype, RelOptInfo *outerrel, RelOptInfo *innerrel,
737 : JoinPathExtraData *extra);
738 : static bool foreign_grouping_ok(PlannerInfo *root, RelOptInfo *grouped_rel,
739 : Node *havingQual);
740 : static List *get_useful_pathkeys_for_relation(PlannerInfo *root,
741 : RelOptInfo *rel);
742 : static List *get_useful_ecs_for_relation(PlannerInfo *root, RelOptInfo *rel);
743 : static void add_paths_with_pathkeys_for_rel(PlannerInfo *root, RelOptInfo *rel,
744 : Path *epq_path, List *restrictlist);
745 : static void add_foreign_grouping_paths(PlannerInfo *root,
746 : RelOptInfo *input_rel,
747 : RelOptInfo *grouped_rel,
748 : GroupPathExtraData *extra);
749 : static void add_foreign_ordered_paths(PlannerInfo *root,
750 : RelOptInfo *input_rel,
751 : RelOptInfo *ordered_rel);
752 : static void add_foreign_final_paths(PlannerInfo *root,
753 : RelOptInfo *input_rel,
754 : RelOptInfo *final_rel,
755 : FinalPathExtraData *extra);
756 : static void apply_server_options(PgFdwRelationInfo *fpinfo);
757 : static void apply_table_options(PgFdwRelationInfo *fpinfo);
758 : static void merge_fdw_options(PgFdwRelationInfo *fpinfo,
759 : const PgFdwRelationInfo *fpinfo_o,
760 : const PgFdwRelationInfo *fpinfo_i);
761 : static int get_batch_size_option(Relation rel);
762 :
763 :
764 : /*
765 : * Foreign-data wrapper handler function: return a struct with pointers
766 : * to my callback routines.
767 : */
768 : Datum
769 710 : postgres_fdw_handler(PG_FUNCTION_ARGS)
770 : {
771 710 : FdwRoutine *routine = makeNode(FdwRoutine);
772 :
773 : /* Functions for scanning foreign tables */
774 710 : routine->GetForeignRelSize = postgresGetForeignRelSize;
775 710 : routine->GetForeignPaths = postgresGetForeignPaths;
776 710 : routine->GetForeignPlan = postgresGetForeignPlan;
777 710 : routine->BeginForeignScan = postgresBeginForeignScan;
778 710 : routine->IterateForeignScan = postgresIterateForeignScan;
779 710 : routine->ReScanForeignScan = postgresReScanForeignScan;
780 710 : routine->EndForeignScan = postgresEndForeignScan;
781 :
782 : /* Functions for updating foreign tables */
783 710 : routine->AddForeignUpdateTargets = postgresAddForeignUpdateTargets;
784 710 : routine->PlanForeignModify = postgresPlanForeignModify;
785 710 : routine->BeginForeignModify = postgresBeginForeignModify;
786 710 : routine->ExecForeignInsert = postgresExecForeignInsert;
787 710 : routine->ExecForeignBatchInsert = postgresExecForeignBatchInsert;
788 710 : routine->GetForeignModifyBatchSize = postgresGetForeignModifyBatchSize;
789 710 : routine->ExecForeignUpdate = postgresExecForeignUpdate;
790 710 : routine->ExecForeignDelete = postgresExecForeignDelete;
791 710 : routine->EndForeignModify = postgresEndForeignModify;
792 710 : routine->BeginForeignInsert = postgresBeginForeignInsert;
793 710 : routine->EndForeignInsert = postgresEndForeignInsert;
794 710 : routine->IsForeignRelUpdatable = postgresIsForeignRelUpdatable;
795 710 : routine->PlanDirectModify = postgresPlanDirectModify;
796 710 : routine->BeginDirectModify = postgresBeginDirectModify;
797 710 : routine->IterateDirectModify = postgresIterateDirectModify;
798 710 : routine->EndDirectModify = postgresEndDirectModify;
799 :
800 : /* Function for EvalPlanQual rechecks */
801 710 : routine->RecheckForeignScan = postgresRecheckForeignScan;
802 : /* Support functions for EXPLAIN */
803 710 : routine->ExplainForeignScan = postgresExplainForeignScan;
804 710 : routine->ExplainForeignModify = postgresExplainForeignModify;
805 710 : routine->ExplainDirectModify = postgresExplainDirectModify;
806 :
807 : /* Support function for TRUNCATE */
808 710 : routine->ExecForeignTruncate = postgresExecForeignTruncate;
809 :
810 : /* Support functions for ANALYZE */
811 710 : routine->AnalyzeForeignTable = postgresAnalyzeForeignTable;
812 710 : routine->ImportForeignStatistics = postgresImportForeignStatistics;
813 :
814 : /* Support functions for IMPORT FOREIGN SCHEMA */
815 710 : routine->ImportForeignSchema = postgresImportForeignSchema;
816 :
817 : /* Support functions for join push-down */
818 710 : routine->GetForeignJoinPaths = postgresGetForeignJoinPaths;
819 :
820 : /* Support functions for upper relation push-down */
821 710 : routine->GetForeignUpperPaths = postgresGetForeignUpperPaths;
822 :
823 : /* Support functions for asynchronous execution */
824 710 : routine->IsForeignPathAsyncCapable = postgresIsForeignPathAsyncCapable;
825 710 : routine->ForeignAsyncRequest = postgresForeignAsyncRequest;
826 710 : routine->ForeignAsyncConfigureWait = postgresForeignAsyncConfigureWait;
827 710 : routine->ForeignAsyncNotify = postgresForeignAsyncNotify;
828 :
829 710 : PG_RETURN_POINTER(routine);
830 : }
831 :
832 : /*
833 : * postgresGetForeignRelSize
834 : * Estimate # of rows and width of the result of the scan
835 : *
836 : * We should consider the effect of all baserestrictinfo clauses here, but
837 : * not any join clauses.
838 : */
839 : static void
840 1216 : postgresGetForeignRelSize(PlannerInfo *root,
841 : RelOptInfo *baserel,
842 : Oid foreigntableid)
843 : {
844 : PgFdwRelationInfo *fpinfo;
845 : ListCell *lc;
846 :
847 : /*
848 : * We use PgFdwRelationInfo to pass various information to subsequent
849 : * functions.
850 : */
851 1216 : fpinfo = palloc0_object(PgFdwRelationInfo);
852 1216 : baserel->fdw_private = fpinfo;
853 :
854 : /* Base foreign tables need to be pushed down always. */
855 1216 : fpinfo->pushdown_safe = true;
856 :
857 : /* Look up foreign-table catalog info. */
858 1216 : fpinfo->table = GetForeignTable(foreigntableid);
859 1216 : fpinfo->server = GetForeignServer(fpinfo->table->serverid);
860 :
861 : /*
862 : * Extract user-settable option values. Note that per-table settings of
863 : * use_remote_estimate, fetch_size and async_capable override per-server
864 : * settings of them, respectively.
865 : */
866 1216 : fpinfo->use_remote_estimate = false;
867 1216 : fpinfo->fdw_startup_cost = DEFAULT_FDW_STARTUP_COST;
868 1216 : fpinfo->fdw_tuple_cost = DEFAULT_FDW_TUPLE_COST;
869 1216 : fpinfo->shippable_extensions = NIL;
870 1216 : fpinfo->fetch_size = 100;
871 1216 : fpinfo->async_capable = false;
872 :
873 1216 : apply_server_options(fpinfo);
874 1216 : apply_table_options(fpinfo);
875 :
876 : /*
877 : * If the table or the server is configured to use remote estimates,
878 : * identify which user to do remote access as during planning. This
879 : * should match what ExecCheckPermissions() does. If we fail due to lack
880 : * of permissions, the query would have failed at runtime anyway.
881 : */
882 1216 : if (fpinfo->use_remote_estimate)
883 : {
884 : Oid userid;
885 :
886 315 : userid = OidIsValid(baserel->userid) ? baserel->userid : GetUserId();
887 315 : fpinfo->user = GetUserMapping(userid, fpinfo->server->serverid);
888 : }
889 : else
890 901 : fpinfo->user = NULL;
891 :
892 : /*
893 : * Identify which baserestrictinfo clauses can be sent to the remote
894 : * server and which can't.
895 : */
896 1214 : classifyConditions(root, baserel, baserel->baserestrictinfo,
897 : &fpinfo->remote_conds, &fpinfo->local_conds);
898 :
899 : /*
900 : * Identify which attributes will need to be retrieved from the remote
901 : * server. These include all attrs needed for joins or final output, plus
902 : * all attrs used in the local_conds. (Note: if we end up using a
903 : * parameterized scan, it's possible that some of the join clauses will be
904 : * sent to the remote and thus we wouldn't really need to retrieve the
905 : * columns used in them. Doesn't seem worth detecting that case though.)
906 : */
907 1214 : fpinfo->attrs_used = NULL;
908 1214 : pull_varattnos((Node *) baserel->reltarget->exprs, baserel->relid,
909 : &fpinfo->attrs_used);
910 1289 : foreach(lc, fpinfo->local_conds)
911 : {
912 75 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
913 :
914 75 : pull_varattnos((Node *) rinfo->clause, baserel->relid,
915 : &fpinfo->attrs_used);
916 : }
917 :
918 : /*
919 : * Compute the selectivity and cost of the local_conds, so we don't have
920 : * to do it over again for each path. The best we can do for these
921 : * conditions is to estimate selectivity on the basis of local statistics.
922 : */
923 2428 : fpinfo->local_conds_sel = clauselist_selectivity(root,
924 : fpinfo->local_conds,
925 1214 : baserel->relid,
926 : JOIN_INNER,
927 : NULL);
928 :
929 1214 : cost_qual_eval(&fpinfo->local_conds_cost, fpinfo->local_conds, root);
930 :
931 : /*
932 : * Set # of retrieved rows and cached relation costs to some negative
933 : * value, so that we can detect when they are set to some sensible values,
934 : * during one (usually the first) of the calls to estimate_path_cost_size.
935 : */
936 1214 : fpinfo->retrieved_rows = -1;
937 1214 : fpinfo->rel_startup_cost = -1;
938 1214 : fpinfo->rel_total_cost = -1;
939 :
940 : /*
941 : * If the table or the server is configured to use remote estimates,
942 : * connect to the foreign server and execute EXPLAIN to estimate the
943 : * number of rows selected by the restriction clauses, as well as the
944 : * average row width. Otherwise, estimate using whatever statistics we
945 : * have locally, in a way similar to ordinary tables.
946 : */
947 1214 : if (fpinfo->use_remote_estimate)
948 : {
949 : /*
950 : * Get cost/size estimates with help of remote server. Save the
951 : * values in fpinfo so we don't need to do it again to generate the
952 : * basic foreign path.
953 : */
954 313 : estimate_path_cost_size(root, baserel, NIL, NIL, NULL,
955 : &fpinfo->rows, &fpinfo->width,
956 : &fpinfo->disabled_nodes,
957 : &fpinfo->startup_cost, &fpinfo->total_cost);
958 :
959 : /* Report estimated baserel size to planner. */
960 313 : baserel->rows = fpinfo->rows;
961 313 : baserel->reltarget->width = fpinfo->width;
962 : }
963 : else
964 : {
965 : /*
966 : * If the foreign table has never been ANALYZEd, it will have
967 : * reltuples < 0, meaning "unknown". We can't do much if we're not
968 : * allowed to consult the remote server, but we can use a hack similar
969 : * to plancat.c's treatment of empty relations: use a minimum size
970 : * estimate of 10 pages, and divide by the column-datatype-based width
971 : * estimate to get the corresponding number of tuples.
972 : */
973 901 : if (baserel->tuples < 0)
974 : {
975 303 : baserel->pages = 10;
976 303 : baserel->tuples =
977 303 : (10 * BLCKSZ) / (baserel->reltarget->width +
978 : MAXALIGN(SizeofHeapTupleHeader));
979 : }
980 :
981 : /* Estimate baserel size as best we can with local statistics. */
982 901 : set_baserel_size_estimates(root, baserel);
983 :
984 : /* Fill in basically-bogus cost estimates for use later. */
985 901 : estimate_path_cost_size(root, baserel, NIL, NIL, NULL,
986 : &fpinfo->rows, &fpinfo->width,
987 : &fpinfo->disabled_nodes,
988 : &fpinfo->startup_cost, &fpinfo->total_cost);
989 : }
990 :
991 : /*
992 : * fpinfo->relation_name gets the numeric rangetable index of the foreign
993 : * table RTE. (If this query gets EXPLAIN'd, we'll convert that to a
994 : * human-readable string at that time.)
995 : */
996 1214 : fpinfo->relation_name = psprintf("%u", baserel->relid);
997 :
998 : /* No outer and inner relations. */
999 1214 : fpinfo->make_outerrel_subquery = false;
1000 1214 : fpinfo->make_innerrel_subquery = false;
1001 1214 : fpinfo->lower_subquery_rels = NULL;
1002 1214 : fpinfo->hidden_subquery_rels = NULL;
1003 : /* Set the relation index. */
1004 1214 : fpinfo->relation_index = baserel->relid;
1005 1214 : }
1006 :
1007 : /*
1008 : * get_useful_ecs_for_relation
1009 : * Determine which EquivalenceClasses might be involved in useful
1010 : * orderings of this relation.
1011 : *
1012 : * This function is in some respects a mirror image of the core function
1013 : * pathkeys_useful_for_merging: for a regular table, we know what indexes
1014 : * we have and want to test whether any of them are useful. For a foreign
1015 : * table, we don't know what indexes are present on the remote side but
1016 : * want to speculate about which ones we'd like to use if they existed.
1017 : *
1018 : * This function returns a list of potentially-useful equivalence classes,
1019 : * but it does not guarantee that an EquivalenceMember exists which contains
1020 : * Vars only from the given relation. For example, given ft1 JOIN t1 ON
1021 : * ft1.x + t1.x = 0, this function will say that the equivalence class
1022 : * containing ft1.x + t1.x is potentially useful. Supposing ft1 is remote and
1023 : * t1 is local (or on a different server), it will turn out that no useful
1024 : * ORDER BY clause can be generated. It's not our job to figure that out
1025 : * here; we're only interested in identifying relevant ECs.
1026 : */
1027 : static List *
1028 538 : get_useful_ecs_for_relation(PlannerInfo *root, RelOptInfo *rel)
1029 : {
1030 538 : List *useful_eclass_list = NIL;
1031 : ListCell *lc;
1032 : Relids relids;
1033 :
1034 : /*
1035 : * First, consider whether any active EC is potentially useful for a merge
1036 : * join against this relation.
1037 : */
1038 538 : if (rel->has_eclass_joins)
1039 : {
1040 700 : foreach(lc, root->eq_classes)
1041 : {
1042 479 : EquivalenceClass *cur_ec = (EquivalenceClass *) lfirst(lc);
1043 :
1044 479 : if (eclass_useful_for_merging(root, cur_ec, rel))
1045 255 : useful_eclass_list = lappend(useful_eclass_list, cur_ec);
1046 : }
1047 : }
1048 :
1049 : /*
1050 : * Next, consider whether there are any non-EC derivable join clauses that
1051 : * are merge-joinable. If the joininfo list is empty, we can exit
1052 : * quickly.
1053 : */
1054 538 : if (rel->joininfo == NIL)
1055 396 : return useful_eclass_list;
1056 :
1057 : /* If this is a child rel, we must use the topmost parent rel to search. */
1058 142 : if (IS_OTHER_REL(rel))
1059 : {
1060 : Assert(!bms_is_empty(rel->top_parent_relids));
1061 20 : relids = rel->top_parent_relids;
1062 : }
1063 : else
1064 122 : relids = rel->relids;
1065 :
1066 : /* Check each join clause in turn. */
1067 345 : foreach(lc, rel->joininfo)
1068 : {
1069 203 : RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(lc);
1070 :
1071 : /* Consider only mergejoinable clauses */
1072 203 : if (restrictinfo->mergeopfamilies == NIL)
1073 14 : continue;
1074 :
1075 : /* Make sure we've got canonical ECs. */
1076 189 : update_mergeclause_eclasses(root, restrictinfo);
1077 :
1078 : /*
1079 : * restrictinfo->mergeopfamilies != NIL is sufficient to guarantee
1080 : * that left_ec and right_ec will be initialized, per comments in
1081 : * distribute_qual_to_rels.
1082 : *
1083 : * We want to identify which side of this merge-joinable clause
1084 : * contains columns from the relation produced by this RelOptInfo. We
1085 : * test for overlap, not containment, because there could be extra
1086 : * relations on either side. For example, suppose we've got something
1087 : * like ((A JOIN B ON A.x = B.x) JOIN C ON A.y = C.y) LEFT JOIN D ON
1088 : * A.y = D.y. The input rel might be the joinrel between A and B, and
1089 : * we'll consider the join clause A.y = D.y. relids contains a
1090 : * relation not involved in the join class (B) and the equivalence
1091 : * class for the left-hand side of the clause contains a relation not
1092 : * involved in the input rel (C). Despite the fact that we have only
1093 : * overlap and not containment in either direction, A.y is potentially
1094 : * useful as a sort column.
1095 : *
1096 : * Note that it's even possible that relids overlaps neither side of
1097 : * the join clause. For example, consider A LEFT JOIN B ON A.x = B.x
1098 : * AND A.x = 1. The clause A.x = 1 will appear in B's joininfo list,
1099 : * but overlaps neither side of B. In that case, we just skip this
1100 : * join clause, since it doesn't suggest a useful sort order for this
1101 : * relation.
1102 : */
1103 189 : if (bms_overlap(relids, restrictinfo->right_ec->ec_relids))
1104 86 : useful_eclass_list = list_append_unique_ptr(useful_eclass_list,
1105 86 : restrictinfo->right_ec);
1106 103 : else if (bms_overlap(relids, restrictinfo->left_ec->ec_relids))
1107 94 : useful_eclass_list = list_append_unique_ptr(useful_eclass_list,
1108 94 : restrictinfo->left_ec);
1109 : }
1110 :
1111 142 : return useful_eclass_list;
1112 : }
1113 :
1114 : /*
1115 : * get_useful_pathkeys_for_relation
1116 : * Determine which orderings of a relation might be useful.
1117 : *
1118 : * Getting data in sorted order can be useful either because the requested
1119 : * order matches the final output ordering for the overall query we're
1120 : * planning, or because it enables an efficient merge join. Here, we try
1121 : * to figure out which pathkeys to consider.
1122 : */
1123 : static List *
1124 1551 : get_useful_pathkeys_for_relation(PlannerInfo *root, RelOptInfo *rel)
1125 : {
1126 1551 : List *useful_pathkeys_list = NIL;
1127 : List *useful_eclass_list;
1128 1551 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private;
1129 1551 : EquivalenceClass *query_ec = NULL;
1130 : ListCell *lc;
1131 :
1132 : /*
1133 : * Pushing the query_pathkeys to the remote server is always worth
1134 : * considering, because it might let us avoid a local sort.
1135 : */
1136 1551 : fpinfo->qp_is_pushdown_safe = false;
1137 1551 : if (root->query_pathkeys)
1138 : {
1139 610 : bool query_pathkeys_ok = true;
1140 :
1141 1152 : foreach(lc, root->query_pathkeys)
1142 : {
1143 779 : PathKey *pathkey = (PathKey *) lfirst(lc);
1144 :
1145 : /*
1146 : * The planner and executor don't have any clever strategy for
1147 : * taking data sorted by a prefix of the query's pathkeys and
1148 : * getting it to be sorted by all of those pathkeys. We'll just
1149 : * end up resorting the entire data set. So, unless we can push
1150 : * down all of the query pathkeys, forget it.
1151 : */
1152 779 : if (!is_foreign_pathkey(root, rel, pathkey))
1153 : {
1154 237 : query_pathkeys_ok = false;
1155 237 : break;
1156 : }
1157 : }
1158 :
1159 610 : if (query_pathkeys_ok)
1160 : {
1161 373 : useful_pathkeys_list = list_make1(list_copy(root->query_pathkeys));
1162 373 : fpinfo->qp_is_pushdown_safe = true;
1163 : }
1164 : }
1165 :
1166 : /*
1167 : * Even if we're not using remote estimates, having the remote side do the
1168 : * sort generally won't be any worse than doing it locally, and it might
1169 : * be much better if the remote side can generate data in the right order
1170 : * without needing a sort at all. However, what we're going to do next is
1171 : * try to generate pathkeys that seem promising for possible merge joins,
1172 : * and that's more speculative. A wrong choice might hurt quite a bit, so
1173 : * bail out if we can't use remote estimates.
1174 : */
1175 1551 : if (!fpinfo->use_remote_estimate)
1176 1013 : return useful_pathkeys_list;
1177 :
1178 : /* Get the list of interesting EquivalenceClasses. */
1179 538 : useful_eclass_list = get_useful_ecs_for_relation(root, rel);
1180 :
1181 : /* Extract unique EC for query, if any, so we don't consider it again. */
1182 538 : if (list_length(root->query_pathkeys) == 1)
1183 : {
1184 177 : PathKey *query_pathkey = linitial(root->query_pathkeys);
1185 :
1186 177 : query_ec = query_pathkey->pk_eclass;
1187 : }
1188 :
1189 : /*
1190 : * As a heuristic, the only pathkeys we consider here are those of length
1191 : * one. It's surely possible to consider more, but since each one we
1192 : * choose to consider will generate a round-trip to the remote side, we
1193 : * need to be a bit cautious here. It would sure be nice to have a local
1194 : * cache of information about remote index definitions...
1195 : */
1196 946 : foreach(lc, useful_eclass_list)
1197 : {
1198 408 : EquivalenceClass *cur_ec = lfirst(lc);
1199 : PathKey *pathkey;
1200 :
1201 : /* If redundant with what we did above, skip it. */
1202 408 : if (cur_ec == query_ec)
1203 31 : continue;
1204 :
1205 : /* Can't push down the sort if the EC's opfamily is not shippable. */
1206 377 : if (!is_shippable(linitial_oid(cur_ec->ec_opfamilies),
1207 : OperatorFamilyRelationId, fpinfo))
1208 0 : continue;
1209 :
1210 : /* If no pushable expression for this rel, skip it. */
1211 377 : if (find_em_for_rel(root, cur_ec, rel) == NULL)
1212 50 : continue;
1213 :
1214 : /* Looks like we can generate a pathkey, so let's do it. */
1215 327 : pathkey = make_canonical_pathkey(root, cur_ec,
1216 327 : linitial_oid(cur_ec->ec_opfamilies),
1217 : COMPARE_LT,
1218 : false);
1219 327 : useful_pathkeys_list = lappend(useful_pathkeys_list,
1220 327 : list_make1(pathkey));
1221 : }
1222 :
1223 538 : return useful_pathkeys_list;
1224 : }
1225 :
1226 : /*
1227 : * postgresGetForeignPaths
1228 : * Create possible scan paths for a scan on the foreign table
1229 : */
1230 : static void
1231 1214 : postgresGetForeignPaths(PlannerInfo *root,
1232 : RelOptInfo *baserel,
1233 : Oid foreigntableid)
1234 : {
1235 1214 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) baserel->fdw_private;
1236 : ForeignPath *path;
1237 : List *ppi_list;
1238 : ListCell *lc;
1239 :
1240 : /*
1241 : * Create simplest ForeignScan path node and add it to baserel. This path
1242 : * corresponds to SeqScan path of regular tables (though depending on what
1243 : * baserestrict conditions we were able to send to remote, there might
1244 : * actually be an indexscan happening there). We already did all the work
1245 : * to estimate cost and size of this path.
1246 : *
1247 : * Although this path uses no join clauses, it could still have required
1248 : * parameterization due to LATERAL refs in its tlist.
1249 : */
1250 1214 : path = create_foreignscan_path(root, baserel,
1251 : NULL, /* default pathtarget */
1252 : fpinfo->rows,
1253 : fpinfo->disabled_nodes,
1254 : fpinfo->startup_cost,
1255 : fpinfo->total_cost,
1256 : NIL, /* no pathkeys */
1257 : baserel->lateral_relids,
1258 : NULL, /* no extra plan */
1259 : NIL, /* no fdw_restrictinfo list */
1260 : NIL); /* no fdw_private list */
1261 1214 : add_path(baserel, (Path *) path);
1262 :
1263 : /* Add paths with pathkeys */
1264 1214 : add_paths_with_pathkeys_for_rel(root, baserel, NULL, NIL);
1265 :
1266 : /*
1267 : * If we're not using remote estimates, stop here. We have no way to
1268 : * estimate whether any join clauses would be worth sending across, so
1269 : * don't bother building parameterized paths.
1270 : */
1271 1214 : if (!fpinfo->use_remote_estimate)
1272 901 : return;
1273 :
1274 : /*
1275 : * Thumb through all join clauses for the rel to identify which outer
1276 : * relations could supply one or more safe-to-send-to-remote join clauses.
1277 : * We'll build a parameterized path for each such outer relation.
1278 : *
1279 : * It's convenient to manage this by representing each candidate outer
1280 : * relation by the ParamPathInfo node for it. We can then use the
1281 : * ppi_clauses list in the ParamPathInfo node directly as a list of the
1282 : * interesting join clauses for that rel. This takes care of the
1283 : * possibility that there are multiple safe join clauses for such a rel,
1284 : * and also ensures that we account for unsafe join clauses that we'll
1285 : * still have to enforce locally (since the parameterized-path machinery
1286 : * insists that we handle all movable clauses).
1287 : */
1288 313 : ppi_list = NIL;
1289 454 : foreach(lc, baserel->joininfo)
1290 : {
1291 141 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
1292 : Relids required_outer;
1293 : ParamPathInfo *param_info;
1294 :
1295 : /* Check if clause can be moved to this rel */
1296 141 : if (!join_clause_is_movable_to(rinfo, baserel))
1297 96 : continue;
1298 :
1299 : /* See if it is safe to send to remote */
1300 45 : if (!is_foreign_expr(root, baserel, rinfo->clause))
1301 7 : continue;
1302 :
1303 : /* Calculate required outer rels for the resulting path */
1304 38 : required_outer = bms_union(rinfo->clause_relids,
1305 38 : baserel->lateral_relids);
1306 : /* We do not want the foreign rel itself listed in required_outer */
1307 38 : required_outer = bms_del_member(required_outer, baserel->relid);
1308 :
1309 : /*
1310 : * required_outer probably can't be empty here, but if it were, we
1311 : * couldn't make a parameterized path.
1312 : */
1313 38 : if (bms_is_empty(required_outer))
1314 0 : continue;
1315 :
1316 : /* Get the ParamPathInfo */
1317 38 : param_info = get_baserel_parampathinfo(root, baserel,
1318 : required_outer);
1319 : Assert(param_info != NULL);
1320 :
1321 : /*
1322 : * Add it to list unless we already have it. Testing pointer equality
1323 : * is OK since get_baserel_parampathinfo won't make duplicates.
1324 : */
1325 38 : ppi_list = list_append_unique_ptr(ppi_list, param_info);
1326 : }
1327 :
1328 : /*
1329 : * The above scan examined only "generic" join clauses, not those that
1330 : * were absorbed into EquivalenceClauses. See if we can make anything out
1331 : * of EquivalenceClauses.
1332 : */
1333 313 : if (baserel->has_eclass_joins)
1334 : {
1335 : /*
1336 : * We repeatedly scan the eclass list looking for column references
1337 : * (or expressions) belonging to the foreign rel. Each time we find
1338 : * one, we generate a list of equivalence joinclauses for it, and then
1339 : * see if any are safe to send to the remote. Repeat till there are
1340 : * no more candidate EC members.
1341 : */
1342 : ec_member_foreign_arg arg;
1343 :
1344 145 : arg.already_used = NIL;
1345 : for (;;)
1346 147 : {
1347 : List *clauses;
1348 :
1349 : /* Make clauses, skipping any that join to lateral_referencers */
1350 292 : arg.current = NULL;
1351 292 : clauses = generate_implied_equalities_for_column(root,
1352 : baserel,
1353 : ec_member_matches_foreign,
1354 : &arg,
1355 : baserel->lateral_referencers);
1356 :
1357 : /* Done if there are no more expressions in the foreign rel */
1358 292 : if (arg.current == NULL)
1359 : {
1360 : Assert(clauses == NIL);
1361 145 : break;
1362 : }
1363 :
1364 : /* Scan the extracted join clauses */
1365 330 : foreach(lc, clauses)
1366 : {
1367 183 : RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
1368 : Relids required_outer;
1369 : ParamPathInfo *param_info;
1370 :
1371 : /* Check if clause can be moved to this rel */
1372 183 : if (!join_clause_is_movable_to(rinfo, baserel))
1373 0 : continue;
1374 :
1375 : /* See if it is safe to send to remote */
1376 183 : if (!is_foreign_expr(root, baserel, rinfo->clause))
1377 7 : continue;
1378 :
1379 : /* Calculate required outer rels for the resulting path */
1380 176 : required_outer = bms_union(rinfo->clause_relids,
1381 176 : baserel->lateral_relids);
1382 176 : required_outer = bms_del_member(required_outer, baserel->relid);
1383 176 : if (bms_is_empty(required_outer))
1384 0 : continue;
1385 :
1386 : /* Get the ParamPathInfo */
1387 176 : param_info = get_baserel_parampathinfo(root, baserel,
1388 : required_outer);
1389 : Assert(param_info != NULL);
1390 :
1391 : /* Add it to list unless we already have it */
1392 176 : ppi_list = list_append_unique_ptr(ppi_list, param_info);
1393 : }
1394 :
1395 : /* Try again, now ignoring the expression we found this time */
1396 147 : arg.already_used = lappend(arg.already_used, arg.current);
1397 : }
1398 : }
1399 :
1400 : /*
1401 : * Now build a path for each useful outer relation.
1402 : */
1403 517 : foreach(lc, ppi_list)
1404 : {
1405 204 : ParamPathInfo *param_info = (ParamPathInfo *) lfirst(lc);
1406 : double rows;
1407 : int width;
1408 : int disabled_nodes;
1409 : Cost startup_cost;
1410 : Cost total_cost;
1411 :
1412 : /* Get a cost estimate from the remote */
1413 204 : estimate_path_cost_size(root, baserel,
1414 : param_info->ppi_clauses, NIL, NULL,
1415 : &rows, &width, &disabled_nodes,
1416 : &startup_cost, &total_cost);
1417 :
1418 : /*
1419 : * ppi_rows currently won't get looked at by anything, but still we
1420 : * may as well ensure that it matches our idea of the rowcount.
1421 : */
1422 204 : param_info->ppi_rows = rows;
1423 :
1424 : /* Make the path */
1425 204 : path = create_foreignscan_path(root, baserel,
1426 : NULL, /* default pathtarget */
1427 : rows,
1428 : disabled_nodes,
1429 : startup_cost,
1430 : total_cost,
1431 : NIL, /* no pathkeys */
1432 : param_info->ppi_req_outer,
1433 : NULL,
1434 : NIL, /* no fdw_restrictinfo list */
1435 : NIL); /* no fdw_private list */
1436 204 : add_path(baserel, (Path *) path);
1437 : }
1438 : }
1439 :
1440 : /*
1441 : * postgresGetForeignPlan
1442 : * Create ForeignScan plan node which implements selected best path
1443 : */
1444 : static ForeignScan *
1445 1028 : postgresGetForeignPlan(PlannerInfo *root,
1446 : RelOptInfo *foreignrel,
1447 : Oid foreigntableid,
1448 : ForeignPath *best_path,
1449 : List *tlist,
1450 : List *scan_clauses,
1451 : Plan *outer_plan)
1452 : {
1453 1028 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
1454 : Index scan_relid;
1455 : List *fdw_private;
1456 1028 : List *remote_exprs = NIL;
1457 1028 : List *local_exprs = NIL;
1458 1028 : List *params_list = NIL;
1459 1028 : List *fdw_scan_tlist = NIL;
1460 1028 : List *fdw_recheck_quals = NIL;
1461 : List *retrieved_attrs;
1462 : StringInfoData sql;
1463 1028 : bool has_final_sort = false;
1464 1028 : bool has_limit = false;
1465 : ListCell *lc;
1466 :
1467 : /*
1468 : * Get FDW private data created by postgresGetForeignUpperPaths(), if any.
1469 : */
1470 1028 : if (best_path->fdw_private)
1471 : {
1472 151 : has_final_sort = boolVal(list_nth(best_path->fdw_private,
1473 : FdwPathPrivateHasFinalSort));
1474 151 : has_limit = boolVal(list_nth(best_path->fdw_private,
1475 : FdwPathPrivateHasLimit));
1476 : }
1477 :
1478 1028 : if (IS_SIMPLE_REL(foreignrel))
1479 : {
1480 : /*
1481 : * For base relations, set scan_relid as the relid of the relation.
1482 : */
1483 741 : scan_relid = foreignrel->relid;
1484 :
1485 : /*
1486 : * In a base-relation scan, we must apply the given scan_clauses.
1487 : *
1488 : * Separate the scan_clauses into those that can be executed remotely
1489 : * and those that can't. baserestrictinfo clauses that were
1490 : * previously determined to be safe or unsafe by classifyConditions
1491 : * are found in fpinfo->remote_conds and fpinfo->local_conds. Anything
1492 : * else in the scan_clauses list will be a join clause, which we have
1493 : * to check for remote-safety.
1494 : *
1495 : * Note: the join clauses we see here should be the exact same ones
1496 : * previously examined by postgresGetForeignPaths. Possibly it'd be
1497 : * worth passing forward the classification work done then, rather
1498 : * than repeating it here.
1499 : *
1500 : * This code must match "extract_actual_clauses(scan_clauses, false)"
1501 : * except for the additional decision about remote versus local
1502 : * execution.
1503 : */
1504 1104 : foreach(lc, scan_clauses)
1505 : {
1506 363 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
1507 :
1508 : /* Ignore any pseudoconstants, they're dealt with elsewhere */
1509 363 : if (rinfo->pseudoconstant)
1510 4 : continue;
1511 :
1512 359 : if (list_member_ptr(fpinfo->remote_conds, rinfo))
1513 273 : remote_exprs = lappend(remote_exprs, rinfo->clause);
1514 86 : else if (list_member_ptr(fpinfo->local_conds, rinfo))
1515 71 : local_exprs = lappend(local_exprs, rinfo->clause);
1516 15 : else if (is_foreign_expr(root, foreignrel, rinfo->clause))
1517 13 : remote_exprs = lappend(remote_exprs, rinfo->clause);
1518 : else
1519 2 : local_exprs = lappend(local_exprs, rinfo->clause);
1520 : }
1521 :
1522 : /*
1523 : * For a base-relation scan, we have to support EPQ recheck, which
1524 : * should recheck all the remote quals.
1525 : */
1526 741 : fdw_recheck_quals = remote_exprs;
1527 : }
1528 : else
1529 : {
1530 : /*
1531 : * Join relation or upper relation - set scan_relid to 0.
1532 : */
1533 287 : scan_relid = 0;
1534 :
1535 : /*
1536 : * For a join rel, baserestrictinfo is NIL and we are not considering
1537 : * parameterization right now, so there should be no scan_clauses for
1538 : * a joinrel or an upper rel either.
1539 : */
1540 : Assert(!scan_clauses);
1541 :
1542 : /*
1543 : * Instead we get the conditions to apply from the fdw_private
1544 : * structure.
1545 : */
1546 287 : remote_exprs = extract_actual_clauses(fpinfo->remote_conds, false);
1547 287 : local_exprs = extract_actual_clauses(fpinfo->local_conds, false);
1548 :
1549 : /*
1550 : * We leave fdw_recheck_quals empty in this case, since we never need
1551 : * to apply EPQ recheck clauses. In the case of a joinrel, EPQ
1552 : * recheck is handled elsewhere --- see postgresGetForeignJoinPaths().
1553 : * If we're planning an upperrel (ie, remote grouping or aggregation)
1554 : * then there's no EPQ to do because SELECT FOR UPDATE wouldn't be
1555 : * allowed, and indeed we *can't* put the remote clauses into
1556 : * fdw_recheck_quals because the unaggregated Vars won't be available
1557 : * locally.
1558 : */
1559 :
1560 : /* Build the list of columns to be fetched from the foreign server. */
1561 287 : fdw_scan_tlist = build_tlist_to_deparse(foreignrel);
1562 :
1563 : /*
1564 : * Ensure that the outer plan produces a tuple whose descriptor
1565 : * matches our scan tuple slot. Also, remove the local conditions
1566 : * from outer plan's quals, lest they be evaluated twice, once by the
1567 : * local plan and once by the scan.
1568 : */
1569 287 : if (outer_plan)
1570 : {
1571 : /*
1572 : * Right now, we only consider grouping and aggregation beyond
1573 : * joins. Queries involving aggregates or grouping do not require
1574 : * EPQ mechanism, hence should not have an outer plan here.
1575 : */
1576 : Assert(!IS_UPPER_REL(foreignrel));
1577 :
1578 : /*
1579 : * First, update the plan's qual list if possible. In some cases
1580 : * the quals might be enforced below the topmost plan level, in
1581 : * which case we'll fail to remove them; it's not worth working
1582 : * harder than this.
1583 : */
1584 29 : foreach(lc, local_exprs)
1585 : {
1586 3 : Node *qual = lfirst(lc);
1587 :
1588 3 : outer_plan->qual = list_delete(outer_plan->qual, qual);
1589 :
1590 : /*
1591 : * For an inner join the local conditions of foreign scan plan
1592 : * can be part of the joinquals as well. (They might also be
1593 : * in the mergequals or hashquals, but we can't touch those
1594 : * without breaking the plan.)
1595 : */
1596 3 : if (IsA(outer_plan, NestLoop) ||
1597 1 : IsA(outer_plan, MergeJoin) ||
1598 1 : IsA(outer_plan, HashJoin))
1599 : {
1600 2 : Join *join_plan = (Join *) outer_plan;
1601 :
1602 2 : if (join_plan->jointype == JOIN_INNER)
1603 2 : join_plan->joinqual = list_delete(join_plan->joinqual,
1604 : qual);
1605 : }
1606 : }
1607 :
1608 : /*
1609 : * Now fix the subplan's tlist --- this might result in inserting
1610 : * a Result node atop the plan tree.
1611 : */
1612 26 : outer_plan = change_plan_targetlist(outer_plan, fdw_scan_tlist,
1613 26 : best_path->path.parallel_safe);
1614 : }
1615 : }
1616 :
1617 : /*
1618 : * Build the query string to be sent for execution, and identify
1619 : * expressions to be sent as parameters.
1620 : */
1621 1028 : initStringInfo(&sql);
1622 1028 : deparseSelectStmtForRel(&sql, root, foreignrel, fdw_scan_tlist,
1623 : remote_exprs, best_path->path.pathkeys,
1624 : has_final_sort, has_limit, false,
1625 : &retrieved_attrs, ¶ms_list);
1626 :
1627 : /* Remember remote_exprs for possible use by postgresPlanDirectModify */
1628 1028 : fpinfo->final_remote_exprs = remote_exprs;
1629 :
1630 : /*
1631 : * Build the fdw_private list that will be available to the executor.
1632 : * Items in the list must match order in enum FdwScanPrivateIndex.
1633 : */
1634 1028 : fdw_private = list_make3(makeString(sql.data),
1635 : retrieved_attrs,
1636 : makeInteger(fpinfo->fetch_size));
1637 1028 : if (IS_JOIN_REL(foreignrel) || IS_UPPER_REL(foreignrel))
1638 287 : fdw_private = lappend(fdw_private,
1639 287 : makeString(fpinfo->relation_name));
1640 :
1641 : /*
1642 : * Create the ForeignScan node for the given relation.
1643 : *
1644 : * Note that the remote parameter expressions are stored in the fdw_exprs
1645 : * field of the finished plan node; we can't keep them in private state
1646 : * because then they wouldn't be subject to later planner processing.
1647 : */
1648 1028 : return make_foreignscan(tlist,
1649 : local_exprs,
1650 : scan_relid,
1651 : params_list,
1652 : fdw_private,
1653 : fdw_scan_tlist,
1654 : fdw_recheck_quals,
1655 : outer_plan);
1656 : }
1657 :
1658 : /*
1659 : * Construct a tuple descriptor for the scan tuples handled by a foreign join.
1660 : */
1661 : static TupleDesc
1662 164 : get_tupdesc_for_join_scan_tuples(ForeignScanState *node)
1663 : {
1664 164 : ForeignScan *fsplan = (ForeignScan *) node->ss.ps.plan;
1665 164 : EState *estate = node->ss.ps.state;
1666 : TupleDesc tupdesc;
1667 :
1668 : /*
1669 : * The core code has already set up a scan tuple slot based on
1670 : * fsplan->fdw_scan_tlist, and this slot's tupdesc is mostly good enough,
1671 : * but there's one case where it isn't. If we have any whole-row row
1672 : * identifier Vars, they may have vartype RECORD, and we need to replace
1673 : * that with the associated table's actual composite type. This ensures
1674 : * that when we read those ROW() expression values from the remote server,
1675 : * we can convert them to a composite type the local server knows.
1676 : */
1677 164 : tupdesc = CreateTupleDescCopy(node->ss.ss_ScanTupleSlot->tts_tupleDescriptor);
1678 685 : for (int i = 0; i < tupdesc->natts; i++)
1679 : {
1680 521 : Form_pg_attribute att = TupleDescAttr(tupdesc, i);
1681 : Var *var;
1682 : RangeTblEntry *rte;
1683 : Oid reltype;
1684 :
1685 : /* Nothing to do if it's not a generic RECORD attribute */
1686 521 : if (att->atttypid != RECORDOID || att->atttypmod >= 0)
1687 518 : continue;
1688 :
1689 : /*
1690 : * If we can't identify the referenced table, do nothing. This'll
1691 : * likely lead to failure later, but perhaps we can muddle through.
1692 : */
1693 3 : var = (Var *) list_nth_node(TargetEntry, fsplan->fdw_scan_tlist,
1694 : i)->expr;
1695 3 : if (!IsA(var, Var) || var->varattno != 0)
1696 0 : continue;
1697 3 : rte = list_nth(estate->es_range_table, var->varno - 1);
1698 3 : if (rte->rtekind != RTE_RELATION)
1699 0 : continue;
1700 3 : reltype = get_rel_type_id(rte->relid);
1701 3 : if (!OidIsValid(reltype))
1702 0 : continue;
1703 3 : att->atttypid = reltype;
1704 : /* shouldn't need to change anything else */
1705 : }
1706 164 : return tupdesc;
1707 : }
1708 :
1709 : /*
1710 : * postgresBeginForeignScan
1711 : * Initiate an executor scan of a foreign PostgreSQL table.
1712 : */
1713 : static void
1714 922 : postgresBeginForeignScan(ForeignScanState *node, int eflags)
1715 : {
1716 922 : ForeignScan *fsplan = (ForeignScan *) node->ss.ps.plan;
1717 922 : EState *estate = node->ss.ps.state;
1718 : PgFdwScanState *fsstate;
1719 : RangeTblEntry *rte;
1720 : Oid userid;
1721 : ForeignTable *table;
1722 : UserMapping *user;
1723 : int rtindex;
1724 : int numParams;
1725 :
1726 : /*
1727 : * Do nothing in EXPLAIN (no ANALYZE) case. node->fdw_state stays NULL.
1728 : */
1729 922 : if (eflags & EXEC_FLAG_EXPLAIN_ONLY)
1730 386 : return;
1731 :
1732 : /*
1733 : * We'll save private state in node->fdw_state.
1734 : */
1735 536 : fsstate = palloc0_object(PgFdwScanState);
1736 536 : node->fdw_state = fsstate;
1737 :
1738 : /*
1739 : * Identify which user to do the remote access as. This should match what
1740 : * ExecCheckPermissions() does.
1741 : */
1742 536 : userid = OidIsValid(fsplan->checkAsUser) ? fsplan->checkAsUser : GetUserId();
1743 536 : if (fsplan->scan.scanrelid > 0)
1744 371 : rtindex = fsplan->scan.scanrelid;
1745 : else
1746 165 : rtindex = bms_next_member(fsplan->fs_base_relids, -1);
1747 536 : rte = exec_rt_fetch(rtindex, estate);
1748 :
1749 : /* Get info about foreign table. */
1750 536 : table = GetForeignTable(rte->relid);
1751 536 : user = GetUserMapping(userid, table->serverid);
1752 :
1753 : /*
1754 : * Get connection to the foreign server. Connection manager will
1755 : * establish new connection if necessary.
1756 : */
1757 536 : fsstate->conn = GetConnection(user, false, &fsstate->conn_state);
1758 :
1759 : /* Assign a unique ID for my cursor */
1760 525 : fsstate->cursor_number = GetCursorNumber(fsstate->conn);
1761 525 : fsstate->cursor_exists = false;
1762 :
1763 : /* Get private info created by planner functions. */
1764 525 : fsstate->query = strVal(list_nth(fsplan->fdw_private,
1765 : FdwScanPrivateSelectSql));
1766 525 : fsstate->retrieved_attrs = (List *) list_nth(fsplan->fdw_private,
1767 : FdwScanPrivateRetrievedAttrs);
1768 525 : fsstate->fetch_size = intVal(list_nth(fsplan->fdw_private,
1769 : FdwScanPrivateFetchSize));
1770 :
1771 : /* Create contexts for batches of tuples and per-tuple temp workspace. */
1772 525 : fsstate->batch_cxt = AllocSetContextCreate(estate->es_query_cxt,
1773 : "postgres_fdw tuple data",
1774 : ALLOCSET_DEFAULT_SIZES);
1775 525 : fsstate->temp_cxt = AllocSetContextCreate(estate->es_query_cxt,
1776 : "postgres_fdw temporary data",
1777 : ALLOCSET_SMALL_SIZES);
1778 :
1779 : /*
1780 : * Get info we'll need for converting data fetched from the foreign server
1781 : * into local representation and error reporting during that process.
1782 : */
1783 525 : if (fsplan->scan.scanrelid > 0)
1784 : {
1785 362 : fsstate->rel = node->ss.ss_currentRelation;
1786 362 : fsstate->tupdesc = RelationGetDescr(fsstate->rel);
1787 : }
1788 : else
1789 : {
1790 163 : fsstate->rel = NULL;
1791 163 : fsstate->tupdesc = get_tupdesc_for_join_scan_tuples(node);
1792 : }
1793 :
1794 525 : fsstate->attinmeta = TupleDescGetAttInMetadata(fsstate->tupdesc);
1795 :
1796 : /*
1797 : * Prepare for processing of parameters used in remote query, if any.
1798 : */
1799 525 : numParams = list_length(fsplan->fdw_exprs);
1800 525 : fsstate->numParams = numParams;
1801 525 : if (numParams > 0)
1802 23 : prepare_query_params((PlanState *) node,
1803 : fsplan->fdw_exprs,
1804 : numParams,
1805 : &fsstate->param_flinfo,
1806 : &fsstate->param_exprs,
1807 : &fsstate->param_values);
1808 :
1809 : /* Set the async-capable flag */
1810 525 : fsstate->async_capable = node->ss.ps.async_capable;
1811 : }
1812 :
1813 : /*
1814 : * postgresIterateForeignScan
1815 : * Retrieve next row from the result set, or clear tuple slot to indicate
1816 : * EOF.
1817 : */
1818 : static TupleTableSlot *
1819 70930 : postgresIterateForeignScan(ForeignScanState *node)
1820 : {
1821 70930 : PgFdwScanState *fsstate = (PgFdwScanState *) node->fdw_state;
1822 70930 : TupleTableSlot *slot = node->ss.ss_ScanTupleSlot;
1823 :
1824 : /*
1825 : * In sync mode, if this is the first call after Begin or ReScan, we need
1826 : * to create the cursor on the remote side. In async mode, we would have
1827 : * already created the cursor before we get here, even if this is the
1828 : * first call after Begin or ReScan.
1829 : */
1830 70930 : if (!fsstate->cursor_exists)
1831 785 : create_cursor(node);
1832 :
1833 : /*
1834 : * Get some more tuples, if we've run out.
1835 : */
1836 70927 : if (fsstate->next_tuple >= fsstate->num_tuples)
1837 : {
1838 : /* In async mode, just clear tuple slot. */
1839 2078 : if (fsstate->async_capable)
1840 32 : return ExecClearTuple(slot);
1841 : /* No point in another fetch if we already detected EOF, though. */
1842 2046 : if (!fsstate->eof_reached)
1843 1362 : fetch_more_data(node);
1844 : /* If we didn't get any tuples, must be end of data. */
1845 2032 : if (fsstate->next_tuple >= fsstate->num_tuples)
1846 755 : return ExecClearTuple(slot);
1847 : }
1848 :
1849 : /*
1850 : * Return the next tuple.
1851 : */
1852 70126 : ExecStoreHeapTuple(fsstate->tuples[fsstate->next_tuple++],
1853 : slot,
1854 : false);
1855 :
1856 70126 : return slot;
1857 : }
1858 :
1859 : /*
1860 : * postgresReScanForeignScan
1861 : * Restart the scan.
1862 : */
1863 : static void
1864 407 : postgresReScanForeignScan(ForeignScanState *node)
1865 : {
1866 407 : PgFdwScanState *fsstate = (PgFdwScanState *) node->fdw_state;
1867 : char sql[64];
1868 : PGresult *res;
1869 :
1870 : /* If we haven't created the cursor yet, nothing to do. */
1871 407 : if (!fsstate->cursor_exists)
1872 50 : return;
1873 :
1874 : /*
1875 : * If the node is async-capable, and an asynchronous fetch for it has
1876 : * begun, the asynchronous fetch might not have yet completed. Check if
1877 : * the node is async-capable, and an asynchronous fetch for it is still in
1878 : * progress; if so, complete the asynchronous fetch before restarting the
1879 : * scan.
1880 : */
1881 369 : if (fsstate->async_capable &&
1882 21 : fsstate->conn_state->pendingAreq &&
1883 2 : fsstate->conn_state->pendingAreq->requestee == (PlanState *) node)
1884 1 : fetch_more_data(node);
1885 :
1886 : /*
1887 : * If any internal parameters affecting this node have changed, we'd
1888 : * better destroy and recreate the cursor. Otherwise, if the remote
1889 : * server is v14 or older, rewinding it should be good enough; if not,
1890 : * rewind is only allowed for scrollable cursors, but we don't have a way
1891 : * to check the scrollability of it, so destroy and recreate it in any
1892 : * case. If we've only fetched zero or one batch, we needn't even rewind
1893 : * the cursor, just rescan what we have.
1894 : */
1895 369 : if (node->ss.ps.chgParam != NULL)
1896 : {
1897 338 : fsstate->cursor_exists = false;
1898 338 : snprintf(sql, sizeof(sql), "CLOSE c%u",
1899 : fsstate->cursor_number);
1900 : }
1901 31 : else if (fsstate->fetch_ct_2 > 1)
1902 : {
1903 19 : if (PQserverVersion(fsstate->conn) < 150000)
1904 0 : snprintf(sql, sizeof(sql), "MOVE BACKWARD ALL IN c%u",
1905 : fsstate->cursor_number);
1906 : else
1907 : {
1908 19 : fsstate->cursor_exists = false;
1909 19 : snprintf(sql, sizeof(sql), "CLOSE c%u",
1910 : fsstate->cursor_number);
1911 : }
1912 : }
1913 : else
1914 : {
1915 : /* Easy: just rescan what we already have in memory, if anything */
1916 12 : fsstate->next_tuple = 0;
1917 12 : return;
1918 : }
1919 :
1920 357 : res = pgfdw_exec_query(fsstate->conn, sql, fsstate->conn_state);
1921 357 : if (PQresultStatus(res) != PGRES_COMMAND_OK)
1922 0 : pgfdw_report_error(res, fsstate->conn, sql);
1923 357 : PQclear(res);
1924 :
1925 : /* Now force a fresh FETCH. */
1926 357 : fsstate->tuples = NULL;
1927 357 : fsstate->num_tuples = 0;
1928 357 : fsstate->next_tuple = 0;
1929 357 : fsstate->fetch_ct_2 = 0;
1930 357 : fsstate->eof_reached = false;
1931 : }
1932 :
1933 : /*
1934 : * postgresEndForeignScan
1935 : * Finish scanning foreign table and dispose objects used for this scan
1936 : */
1937 : static void
1938 881 : postgresEndForeignScan(ForeignScanState *node)
1939 : {
1940 881 : PgFdwScanState *fsstate = (PgFdwScanState *) node->fdw_state;
1941 :
1942 : /* if fsstate is NULL, we are in EXPLAIN; nothing to do */
1943 881 : if (fsstate == NULL)
1944 386 : return;
1945 :
1946 : /* Close the cursor if open, to prevent accumulation of cursors */
1947 495 : if (fsstate->cursor_exists)
1948 467 : close_cursor(fsstate->conn, fsstate->cursor_number,
1949 : fsstate->conn_state);
1950 :
1951 : /* Release remote connection */
1952 494 : ReleaseConnection(fsstate->conn);
1953 494 : fsstate->conn = NULL;
1954 :
1955 : /* MemoryContexts will be deleted automatically. */
1956 : }
1957 :
1958 : /*
1959 : * postgresAddForeignUpdateTargets
1960 : * Add resjunk column(s) needed for update/delete on a foreign table
1961 : */
1962 : static void
1963 189 : postgresAddForeignUpdateTargets(PlannerInfo *root,
1964 : Index rtindex,
1965 : RangeTblEntry *target_rte,
1966 : Relation target_relation)
1967 : {
1968 : Var *var;
1969 :
1970 : /*
1971 : * In postgres_fdw, what we need is the ctid, same as for a regular table.
1972 : */
1973 :
1974 : /* Make a Var representing the desired value */
1975 189 : var = makeVar(rtindex,
1976 : SelfItemPointerAttributeNumber,
1977 : TIDOID,
1978 : -1,
1979 : InvalidOid,
1980 : 0);
1981 :
1982 : /* Register it as a row-identity column needed by this target rel */
1983 189 : add_row_identity_var(root, var, rtindex, "ctid");
1984 189 : }
1985 :
1986 : /*
1987 : * postgresPlanForeignModify
1988 : * Plan an insert/update/delete operation on a foreign table
1989 : */
1990 : static List *
1991 170 : postgresPlanForeignModify(PlannerInfo *root,
1992 : ModifyTable *plan,
1993 : Index resultRelation,
1994 : int subplan_index)
1995 : {
1996 170 : CmdType operation = plan->operation;
1997 170 : RangeTblEntry *rte = planner_rt_fetch(resultRelation, root);
1998 : Relation rel;
1999 : StringInfoData sql;
2000 170 : List *targetAttrs = NIL;
2001 170 : List *withCheckOptionList = NIL;
2002 170 : List *returningList = NIL;
2003 170 : List *retrieved_attrs = NIL;
2004 170 : bool doNothing = false;
2005 170 : int values_end_len = -1;
2006 :
2007 170 : initStringInfo(&sql);
2008 :
2009 : /*
2010 : * Core code already has some lock on each rel being planned, so we can
2011 : * use NoLock here.
2012 : */
2013 170 : rel = table_open(rte->relid, NoLock);
2014 :
2015 : /*
2016 : * In an INSERT, we transmit all columns that are defined in the foreign
2017 : * table. In an UPDATE, if there are BEFORE ROW UPDATE triggers on the
2018 : * foreign table, we transmit all columns like INSERT; else we transmit
2019 : * only columns that were explicitly targets of the UPDATE, so as to avoid
2020 : * unnecessary data transmission. (We can't do that for INSERT since we
2021 : * would miss sending default values for columns not listed in the source
2022 : * statement, and for UPDATE if there are BEFORE ROW UPDATE triggers since
2023 : * those triggers might change values for non-target columns, in which
2024 : * case we would miss sending changed values for those columns.)
2025 : */
2026 170 : if (operation == CMD_INSERT ||
2027 60 : (operation == CMD_UPDATE &&
2028 60 : rel->trigdesc &&
2029 18 : rel->trigdesc->trig_update_before_row))
2030 103 : {
2031 103 : TupleDesc tupdesc = RelationGetDescr(rel);
2032 : int attnum;
2033 :
2034 434 : for (attnum = 1; attnum <= tupdesc->natts; attnum++)
2035 : {
2036 331 : CompactAttribute *attr = TupleDescCompactAttr(tupdesc, attnum - 1);
2037 :
2038 331 : if (!attr->attisdropped)
2039 314 : targetAttrs = lappend_int(targetAttrs, attnum);
2040 : }
2041 : }
2042 67 : else if (operation == CMD_UPDATE)
2043 : {
2044 : int col;
2045 45 : RelOptInfo *rel = find_base_rel(root, resultRelation);
2046 45 : Bitmapset *allUpdatedCols = get_rel_all_updated_cols(root, rel);
2047 :
2048 45 : col = -1;
2049 100 : while ((col = bms_next_member(allUpdatedCols, col)) >= 0)
2050 : {
2051 : /* bit numbers are offset by FirstLowInvalidHeapAttributeNumber */
2052 55 : AttrNumber attno = col + FirstLowInvalidHeapAttributeNumber;
2053 :
2054 55 : if (attno <= InvalidAttrNumber) /* shouldn't happen */
2055 0 : elog(ERROR, "system-column update is not supported");
2056 55 : targetAttrs = lappend_int(targetAttrs, attno);
2057 : }
2058 : }
2059 :
2060 : /*
2061 : * Extract the relevant WITH CHECK OPTION list if any.
2062 : */
2063 170 : if (plan->withCheckOptionLists)
2064 16 : withCheckOptionList = (List *) list_nth(plan->withCheckOptionLists,
2065 : subplan_index);
2066 :
2067 : /*
2068 : * Extract the relevant RETURNING list if any.
2069 : */
2070 170 : if (plan->returningLists)
2071 32 : returningList = (List *) list_nth(plan->returningLists, subplan_index);
2072 :
2073 : /*
2074 : * ON CONFLICT DO NOTHING/SELECT/UPDATE with inference specification
2075 : * should have already been rejected in the optimizer, as presently there
2076 : * is no way to recognize an arbiter index on a foreign table. Only DO
2077 : * NOTHING is supported without an inference specification.
2078 : */
2079 170 : if (plan->onConflictAction == ONCONFLICT_NOTHING)
2080 1 : doNothing = true;
2081 169 : else if (plan->onConflictAction != ONCONFLICT_NONE)
2082 0 : elog(ERROR, "unexpected ON CONFLICT specification: %d",
2083 : (int) plan->onConflictAction);
2084 :
2085 : /*
2086 : * Construct the SQL command string.
2087 : */
2088 170 : switch (operation)
2089 : {
2090 88 : case CMD_INSERT:
2091 88 : deparseInsertSql(&sql, rte, resultRelation, rel,
2092 : targetAttrs, doNothing,
2093 : withCheckOptionList, returningList,
2094 : &retrieved_attrs, &values_end_len);
2095 88 : break;
2096 60 : case CMD_UPDATE:
2097 60 : deparseUpdateSql(&sql, rte, resultRelation, rel,
2098 : targetAttrs,
2099 : withCheckOptionList, returningList,
2100 : &retrieved_attrs);
2101 60 : break;
2102 22 : case CMD_DELETE:
2103 22 : deparseDeleteSql(&sql, rte, resultRelation, rel,
2104 : returningList,
2105 : &retrieved_attrs);
2106 22 : break;
2107 0 : default:
2108 0 : elog(ERROR, "unexpected operation: %d", (int) operation);
2109 : break;
2110 : }
2111 :
2112 170 : table_close(rel, NoLock);
2113 :
2114 : /*
2115 : * Build the fdw_private list that will be available to the executor.
2116 : * Items in the list must match enum FdwModifyPrivateIndex, above.
2117 : */
2118 170 : return list_make5(makeString(sql.data),
2119 : targetAttrs,
2120 : makeInteger(values_end_len),
2121 : makeBoolean((retrieved_attrs != NIL)),
2122 : retrieved_attrs);
2123 : }
2124 :
2125 : /*
2126 : * postgresBeginForeignModify
2127 : * Begin an insert/update/delete operation on a foreign table
2128 : */
2129 : static void
2130 170 : postgresBeginForeignModify(ModifyTableState *mtstate,
2131 : ResultRelInfo *resultRelInfo,
2132 : List *fdw_private,
2133 : int subplan_index,
2134 : int eflags)
2135 : {
2136 : PgFdwModifyState *fmstate;
2137 : char *query;
2138 : List *target_attrs;
2139 : bool has_returning;
2140 : int values_end_len;
2141 : List *retrieved_attrs;
2142 : RangeTblEntry *rte;
2143 :
2144 : /*
2145 : * Do nothing in EXPLAIN (no ANALYZE) case. resultRelInfo->ri_FdwState
2146 : * stays NULL.
2147 : */
2148 170 : if (eflags & EXEC_FLAG_EXPLAIN_ONLY)
2149 46 : return;
2150 :
2151 : /* Deconstruct fdw_private data. */
2152 124 : query = strVal(list_nth(fdw_private,
2153 : FdwModifyPrivateUpdateSql));
2154 124 : target_attrs = (List *) list_nth(fdw_private,
2155 : FdwModifyPrivateTargetAttnums);
2156 124 : values_end_len = intVal(list_nth(fdw_private,
2157 : FdwModifyPrivateLen));
2158 124 : has_returning = boolVal(list_nth(fdw_private,
2159 : FdwModifyPrivateHasReturning));
2160 124 : retrieved_attrs = (List *) list_nth(fdw_private,
2161 : FdwModifyPrivateRetrievedAttrs);
2162 :
2163 : /* Find RTE. */
2164 124 : rte = exec_rt_fetch(resultRelInfo->ri_RangeTableIndex,
2165 : mtstate->ps.state);
2166 :
2167 : /* Construct an execution state. */
2168 124 : fmstate = create_foreign_modify(mtstate->ps.state,
2169 : rte,
2170 : resultRelInfo,
2171 : mtstate->operation,
2172 124 : outerPlanState(mtstate)->plan,
2173 : query,
2174 : target_attrs,
2175 : values_end_len,
2176 : has_returning,
2177 : retrieved_attrs);
2178 :
2179 124 : resultRelInfo->ri_FdwState = fmstate;
2180 : }
2181 :
2182 : /*
2183 : * postgresExecForeignInsert
2184 : * Insert one row into a foreign table
2185 : */
2186 : static TupleTableSlot *
2187 892 : postgresExecForeignInsert(EState *estate,
2188 : ResultRelInfo *resultRelInfo,
2189 : TupleTableSlot *slot,
2190 : TupleTableSlot *planSlot)
2191 : {
2192 892 : PgFdwModifyState *fmstate = (PgFdwModifyState *) resultRelInfo->ri_FdwState;
2193 : TupleTableSlot **rslot;
2194 892 : int numSlots = 1;
2195 :
2196 : /*
2197 : * If the fmstate has aux_fmstate set, use the aux_fmstate (see
2198 : * postgresBeginForeignInsert())
2199 : */
2200 892 : if (fmstate->aux_fmstate)
2201 0 : resultRelInfo->ri_FdwState = fmstate->aux_fmstate;
2202 892 : rslot = execute_foreign_modify(estate, resultRelInfo, CMD_INSERT,
2203 : &slot, &planSlot, &numSlots);
2204 : /* Revert that change */
2205 888 : if (fmstate->aux_fmstate)
2206 0 : resultRelInfo->ri_FdwState = fmstate;
2207 :
2208 888 : return rslot ? *rslot : NULL;
2209 : }
2210 :
2211 : /*
2212 : * postgresExecForeignBatchInsert
2213 : * Insert multiple rows into a foreign table
2214 : */
2215 : static TupleTableSlot **
2216 42 : postgresExecForeignBatchInsert(EState *estate,
2217 : ResultRelInfo *resultRelInfo,
2218 : TupleTableSlot **slots,
2219 : TupleTableSlot **planSlots,
2220 : int *numSlots)
2221 : {
2222 42 : PgFdwModifyState *fmstate = (PgFdwModifyState *) resultRelInfo->ri_FdwState;
2223 : TupleTableSlot **rslot;
2224 :
2225 : /*
2226 : * If the fmstate has aux_fmstate set, use the aux_fmstate (see
2227 : * postgresBeginForeignInsert())
2228 : */
2229 42 : if (fmstate->aux_fmstate)
2230 0 : resultRelInfo->ri_FdwState = fmstate->aux_fmstate;
2231 42 : rslot = execute_foreign_modify(estate, resultRelInfo, CMD_INSERT,
2232 : slots, planSlots, numSlots);
2233 : /* Revert that change */
2234 41 : if (fmstate->aux_fmstate)
2235 0 : resultRelInfo->ri_FdwState = fmstate;
2236 :
2237 41 : return rslot;
2238 : }
2239 :
2240 : /*
2241 : * postgresGetForeignModifyBatchSize
2242 : * Determine the maximum number of tuples that can be inserted in bulk
2243 : *
2244 : * Returns the batch size specified for server or table. When batching is not
2245 : * allowed (e.g. for tables with BEFORE/AFTER ROW triggers or with RETURNING
2246 : * clause), returns 1.
2247 : */
2248 : static int
2249 146 : postgresGetForeignModifyBatchSize(ResultRelInfo *resultRelInfo)
2250 : {
2251 : int batch_size;
2252 146 : PgFdwModifyState *fmstate = (PgFdwModifyState *) resultRelInfo->ri_FdwState;
2253 :
2254 : /* should be called only once */
2255 : Assert(resultRelInfo->ri_BatchSize == 0);
2256 :
2257 : /*
2258 : * Should never get called when the insert is being performed on a table
2259 : * that is also among the target relations of an UPDATE operation, because
2260 : * postgresBeginForeignInsert() currently rejects such insert attempts.
2261 : */
2262 : Assert(fmstate == NULL || fmstate->aux_fmstate == NULL);
2263 :
2264 : /*
2265 : * In EXPLAIN without ANALYZE, ri_FdwState is NULL, so we have to lookup
2266 : * the option directly in server/table options. Otherwise just use the
2267 : * value we determined earlier.
2268 : */
2269 146 : if (fmstate)
2270 133 : batch_size = fmstate->batch_size;
2271 : else
2272 13 : batch_size = get_batch_size_option(resultRelInfo->ri_RelationDesc);
2273 :
2274 : /*
2275 : * Disable batching when we have to use RETURNING, there are any
2276 : * BEFORE/AFTER ROW INSERT triggers on the foreign table, or there are any
2277 : * WITH CHECK OPTION constraints from parent views.
2278 : *
2279 : * When there are any BEFORE ROW INSERT triggers on the table, we can't
2280 : * support it, because such triggers might query the table we're inserting
2281 : * into and act differently if the tuples that have already been processed
2282 : * and prepared for insertion are not there.
2283 : */
2284 146 : if (resultRelInfo->ri_projectReturning != NULL ||
2285 125 : resultRelInfo->ri_WithCheckOptions != NIL ||
2286 116 : (resultRelInfo->ri_TrigDesc &&
2287 14 : (resultRelInfo->ri_TrigDesc->trig_insert_before_row ||
2288 1 : resultRelInfo->ri_TrigDesc->trig_insert_after_row)))
2289 44 : return 1;
2290 :
2291 : /*
2292 : * If the foreign table has no columns, disable batching as the INSERT
2293 : * syntax doesn't allow batching multiple empty rows into a zero-column
2294 : * table in a single statement. This is needed for COPY FROM, in which
2295 : * case fmstate must be non-NULL.
2296 : */
2297 102 : if (fmstate && list_length(fmstate->target_attrs) == 0)
2298 1 : return 1;
2299 :
2300 : /*
2301 : * Otherwise use the batch size specified for server/table. The number of
2302 : * parameters in a batch is limited to 65535 (uint16), so make sure we
2303 : * don't exceed this limit by using the maximum batch_size possible.
2304 : */
2305 101 : if (fmstate && fmstate->p_nums > 0)
2306 93 : batch_size = Min(batch_size, PQ_QUERY_PARAM_MAX_LIMIT / fmstate->p_nums);
2307 :
2308 101 : return batch_size;
2309 : }
2310 :
2311 : /*
2312 : * postgresExecForeignUpdate
2313 : * Update one row in a foreign table
2314 : */
2315 : static TupleTableSlot *
2316 95 : postgresExecForeignUpdate(EState *estate,
2317 : ResultRelInfo *resultRelInfo,
2318 : TupleTableSlot *slot,
2319 : TupleTableSlot *planSlot)
2320 : {
2321 : TupleTableSlot **rslot;
2322 95 : int numSlots = 1;
2323 :
2324 95 : rslot = execute_foreign_modify(estate, resultRelInfo, CMD_UPDATE,
2325 : &slot, &planSlot, &numSlots);
2326 :
2327 95 : return rslot ? rslot[0] : NULL;
2328 : }
2329 :
2330 : /*
2331 : * postgresExecForeignDelete
2332 : * Delete one row from a foreign table
2333 : */
2334 : static TupleTableSlot *
2335 23 : postgresExecForeignDelete(EState *estate,
2336 : ResultRelInfo *resultRelInfo,
2337 : TupleTableSlot *slot,
2338 : TupleTableSlot *planSlot)
2339 : {
2340 : TupleTableSlot **rslot;
2341 23 : int numSlots = 1;
2342 :
2343 23 : rslot = execute_foreign_modify(estate, resultRelInfo, CMD_DELETE,
2344 : &slot, &planSlot, &numSlots);
2345 :
2346 23 : return rslot ? rslot[0] : NULL;
2347 : }
2348 :
2349 : /*
2350 : * postgresEndForeignModify
2351 : * Finish an insert/update/delete operation on a foreign table
2352 : */
2353 : static void
2354 156 : postgresEndForeignModify(EState *estate,
2355 : ResultRelInfo *resultRelInfo)
2356 : {
2357 156 : PgFdwModifyState *fmstate = (PgFdwModifyState *) resultRelInfo->ri_FdwState;
2358 :
2359 : /* If fmstate is NULL, we are in EXPLAIN; nothing to do */
2360 156 : if (fmstate == NULL)
2361 46 : return;
2362 :
2363 : /* Destroy the execution state */
2364 110 : finish_foreign_modify(fmstate);
2365 : }
2366 :
2367 : /*
2368 : * postgresBeginForeignInsert
2369 : * Begin an insert operation on a foreign table
2370 : */
2371 : static void
2372 64 : postgresBeginForeignInsert(ModifyTableState *mtstate,
2373 : ResultRelInfo *resultRelInfo)
2374 : {
2375 : PgFdwModifyState *fmstate;
2376 64 : ModifyTable *plan = castNode(ModifyTable, mtstate->ps.plan);
2377 64 : EState *estate = mtstate->ps.state;
2378 : Index resultRelation;
2379 64 : Relation rel = resultRelInfo->ri_RelationDesc;
2380 : RangeTblEntry *rte;
2381 64 : TupleDesc tupdesc = RelationGetDescr(rel);
2382 : int attnum;
2383 : int values_end_len;
2384 : StringInfoData sql;
2385 64 : List *targetAttrs = NIL;
2386 64 : List *retrieved_attrs = NIL;
2387 64 : bool doNothing = false;
2388 :
2389 : /*
2390 : * If the foreign table we are about to insert routed rows into is also an
2391 : * UPDATE subplan result rel that will be updated later, proceeding with
2392 : * the INSERT will result in the later UPDATE incorrectly modifying those
2393 : * routed rows, so prevent the INSERT --- it would be nice if we could
2394 : * handle this case; but for now, throw an error for safety.
2395 : */
2396 64 : if (plan && plan->operation == CMD_UPDATE &&
2397 9 : (resultRelInfo->ri_usesFdwDirectModify ||
2398 5 : resultRelInfo->ri_FdwState))
2399 6 : ereport(ERROR,
2400 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2401 : errmsg("cannot route tuples into foreign table to be updated \"%s\"",
2402 : RelationGetRelationName(rel))));
2403 :
2404 58 : initStringInfo(&sql);
2405 :
2406 : /* We transmit all columns that are defined in the foreign table. */
2407 173 : for (attnum = 1; attnum <= tupdesc->natts; attnum++)
2408 : {
2409 115 : CompactAttribute *attr = TupleDescCompactAttr(tupdesc, attnum - 1);
2410 :
2411 115 : if (!attr->attisdropped)
2412 113 : targetAttrs = lappend_int(targetAttrs, attnum);
2413 : }
2414 :
2415 : /* Check if we add the ON CONFLICT clause to the remote query. */
2416 58 : if (plan)
2417 : {
2418 34 : OnConflictAction onConflictAction = plan->onConflictAction;
2419 :
2420 : /* We only support DO NOTHING without an inference specification. */
2421 34 : if (onConflictAction == ONCONFLICT_NOTHING)
2422 2 : doNothing = true;
2423 32 : else if (onConflictAction != ONCONFLICT_NONE)
2424 0 : elog(ERROR, "unexpected ON CONFLICT specification: %d",
2425 : (int) onConflictAction);
2426 : }
2427 :
2428 : /*
2429 : * If the foreign table is a partition that doesn't have a corresponding
2430 : * RTE entry, we need to create a new RTE describing the foreign table for
2431 : * use by deparseInsertSql and create_foreign_modify() below, after first
2432 : * copying the parent's RTE and modifying some fields to describe the
2433 : * foreign partition to work on. However, if this is invoked by UPDATE,
2434 : * the existing RTE may already correspond to this partition if it is one
2435 : * of the UPDATE subplan target rels; in that case, we can just use the
2436 : * existing RTE as-is.
2437 : */
2438 58 : if (resultRelInfo->ri_RangeTableIndex == 0)
2439 : {
2440 40 : ResultRelInfo *rootResultRelInfo = resultRelInfo->ri_RootResultRelInfo;
2441 :
2442 40 : rte = exec_rt_fetch(rootResultRelInfo->ri_RangeTableIndex, estate);
2443 40 : rte = copyObject(rte);
2444 40 : rte->relid = RelationGetRelid(rel);
2445 40 : rte->relkind = RELKIND_FOREIGN_TABLE;
2446 :
2447 : /*
2448 : * For UPDATE, we must use the RT index of the first subplan target
2449 : * rel's RTE, because the core code would have built expressions for
2450 : * the partition, such as RETURNING, using that RT index as varno of
2451 : * Vars contained in those expressions.
2452 : */
2453 40 : if (plan && plan->operation == CMD_UPDATE &&
2454 3 : rootResultRelInfo->ri_RangeTableIndex == plan->rootRelation)
2455 3 : resultRelation = mtstate->resultRelInfo[0].ri_RangeTableIndex;
2456 : else
2457 37 : resultRelation = rootResultRelInfo->ri_RangeTableIndex;
2458 : }
2459 : else
2460 : {
2461 18 : resultRelation = resultRelInfo->ri_RangeTableIndex;
2462 18 : rte = exec_rt_fetch(resultRelation, estate);
2463 : }
2464 :
2465 : /* Construct the SQL command string. */
2466 58 : deparseInsertSql(&sql, rte, resultRelation, rel, targetAttrs, doNothing,
2467 : resultRelInfo->ri_WithCheckOptions,
2468 : resultRelInfo->ri_returningList,
2469 : &retrieved_attrs, &values_end_len);
2470 :
2471 : /* Construct an execution state. */
2472 58 : fmstate = create_foreign_modify(mtstate->ps.state,
2473 : rte,
2474 : resultRelInfo,
2475 : CMD_INSERT,
2476 : NULL,
2477 : sql.data,
2478 : targetAttrs,
2479 : values_end_len,
2480 : retrieved_attrs != NIL,
2481 : retrieved_attrs);
2482 :
2483 : /*
2484 : * If the given resultRelInfo already has PgFdwModifyState set, it means
2485 : * the foreign table is an UPDATE subplan result rel; in which case, store
2486 : * the resulting state into the aux_fmstate of the PgFdwModifyState.
2487 : */
2488 58 : if (resultRelInfo->ri_FdwState)
2489 : {
2490 : Assert(plan && plan->operation == CMD_UPDATE);
2491 : Assert(resultRelInfo->ri_usesFdwDirectModify == false);
2492 0 : ((PgFdwModifyState *) resultRelInfo->ri_FdwState)->aux_fmstate = fmstate;
2493 : }
2494 : else
2495 58 : resultRelInfo->ri_FdwState = fmstate;
2496 58 : }
2497 :
2498 : /*
2499 : * postgresEndForeignInsert
2500 : * Finish an insert operation on a foreign table
2501 : */
2502 : static void
2503 50 : postgresEndForeignInsert(EState *estate,
2504 : ResultRelInfo *resultRelInfo)
2505 : {
2506 50 : PgFdwModifyState *fmstate = (PgFdwModifyState *) resultRelInfo->ri_FdwState;
2507 :
2508 : Assert(fmstate != NULL);
2509 :
2510 : /*
2511 : * If the fmstate has aux_fmstate set, get the aux_fmstate (see
2512 : * postgresBeginForeignInsert())
2513 : */
2514 50 : if (fmstate->aux_fmstate)
2515 0 : fmstate = fmstate->aux_fmstate;
2516 :
2517 : /* Destroy the execution state */
2518 50 : finish_foreign_modify(fmstate);
2519 50 : }
2520 :
2521 : /*
2522 : * postgresIsForeignRelUpdatable
2523 : * Determine whether a foreign table supports INSERT, UPDATE and/or
2524 : * DELETE.
2525 : */
2526 : static int
2527 338 : postgresIsForeignRelUpdatable(Relation rel)
2528 : {
2529 : bool updatable;
2530 : ForeignTable *table;
2531 : ForeignServer *server;
2532 : ListCell *lc;
2533 :
2534 : /*
2535 : * By default, all postgres_fdw foreign tables are assumed updatable. This
2536 : * can be overridden by a per-server setting, which in turn can be
2537 : * overridden by a per-table setting.
2538 : */
2539 338 : updatable = true;
2540 :
2541 338 : table = GetForeignTable(RelationGetRelid(rel));
2542 338 : server = GetForeignServer(table->serverid);
2543 :
2544 1511 : foreach(lc, server->options)
2545 : {
2546 1173 : DefElem *def = (DefElem *) lfirst(lc);
2547 :
2548 1173 : if (strcmp(def->defname, "updatable") == 0)
2549 0 : updatable = defGetBoolean(def);
2550 : }
2551 814 : foreach(lc, table->options)
2552 : {
2553 476 : DefElem *def = (DefElem *) lfirst(lc);
2554 :
2555 476 : if (strcmp(def->defname, "updatable") == 0)
2556 0 : updatable = defGetBoolean(def);
2557 : }
2558 :
2559 : /*
2560 : * Currently "updatable" means support for INSERT, UPDATE and DELETE.
2561 : */
2562 : return updatable ?
2563 338 : (1 << CMD_INSERT) | (1 << CMD_UPDATE) | (1 << CMD_DELETE) : 0;
2564 : }
2565 :
2566 : /*
2567 : * postgresRecheckForeignScan
2568 : * Execute a local join execution plan for a foreign join
2569 : */
2570 : static bool
2571 5 : postgresRecheckForeignScan(ForeignScanState *node, TupleTableSlot *slot)
2572 : {
2573 5 : Index scanrelid = ((Scan *) node->ss.ps.plan)->scanrelid;
2574 5 : PlanState *outerPlan = outerPlanState(node);
2575 : TupleTableSlot *result;
2576 :
2577 : /* For base foreign relations, it suffices to set fdw_recheck_quals */
2578 5 : if (scanrelid > 0)
2579 3 : return true;
2580 :
2581 : Assert(outerPlan != NULL);
2582 :
2583 : /* Execute a local join execution plan */
2584 2 : result = ExecProcNode(outerPlan);
2585 2 : if (TupIsNull(result))
2586 1 : return false;
2587 :
2588 : /* Store result in the given slot */
2589 1 : ExecCopySlot(slot, result);
2590 :
2591 1 : return true;
2592 : }
2593 :
2594 : /*
2595 : * find_modifytable_subplan
2596 : * Helper routine for postgresPlanDirectModify to find the
2597 : * ModifyTable subplan node that scans the specified RTI.
2598 : *
2599 : * Returns NULL if the subplan couldn't be identified. That's not a fatal
2600 : * error condition, we just abandon trying to do the update directly.
2601 : */
2602 : static ForeignScan *
2603 131 : find_modifytable_subplan(PlannerInfo *root,
2604 : ModifyTable *plan,
2605 : Index rtindex,
2606 : int subplan_index)
2607 : {
2608 131 : Plan *subplan = outerPlan(plan);
2609 :
2610 : /*
2611 : * The cases we support are (1) the desired ForeignScan is the immediate
2612 : * child of ModifyTable, or (2) it is the subplan_index'th child of an
2613 : * Append node that is the immediate child of ModifyTable. There is no
2614 : * point in looking further down, as that would mean that local joins are
2615 : * involved, so we can't do the update directly.
2616 : *
2617 : * There could be a Result atop the Append too, acting to compute the
2618 : * UPDATE targetlist values. We ignore that here; the tlist will be
2619 : * checked by our caller.
2620 : *
2621 : * In principle we could examine all the children of the Append, but it's
2622 : * currently unlikely that the core planner would generate such a plan
2623 : * with the children out-of-order. Moreover, such a search risks costing
2624 : * O(N^2) time when there are a lot of children.
2625 : */
2626 131 : if (IsA(subplan, Append))
2627 : {
2628 33 : Append *appendplan = (Append *) subplan;
2629 :
2630 33 : if (subplan_index < list_length(appendplan->appendplans))
2631 33 : subplan = (Plan *) list_nth(appendplan->appendplans, subplan_index);
2632 : }
2633 98 : else if (IsA(subplan, Result) &&
2634 6 : outerPlan(subplan) != NULL &&
2635 5 : IsA(outerPlan(subplan), Append))
2636 : {
2637 5 : Append *appendplan = (Append *) outerPlan(subplan);
2638 :
2639 5 : if (subplan_index < list_length(appendplan->appendplans))
2640 5 : subplan = (Plan *) list_nth(appendplan->appendplans, subplan_index);
2641 : }
2642 :
2643 : /* Now, have we got a ForeignScan on the desired rel? */
2644 131 : if (IsA(subplan, ForeignScan))
2645 : {
2646 114 : ForeignScan *fscan = (ForeignScan *) subplan;
2647 :
2648 114 : if (bms_is_member(rtindex, fscan->fs_base_relids))
2649 114 : return fscan;
2650 : }
2651 :
2652 17 : return NULL;
2653 : }
2654 :
2655 : /*
2656 : * postgresPlanDirectModify
2657 : * Consider a direct foreign table modification
2658 : *
2659 : * Decide whether it is safe to modify a foreign table directly, and if so,
2660 : * rewrite subplan accordingly.
2661 : */
2662 : static bool
2663 195 : postgresPlanDirectModify(PlannerInfo *root,
2664 : ModifyTable *plan,
2665 : Index resultRelation,
2666 : int subplan_index)
2667 : {
2668 195 : CmdType operation = plan->operation;
2669 : RelOptInfo *foreignrel;
2670 : RangeTblEntry *rte;
2671 : PgFdwRelationInfo *fpinfo;
2672 : Relation rel;
2673 : StringInfoData sql;
2674 : ForeignScan *fscan;
2675 195 : List *processed_tlist = NIL;
2676 195 : List *targetAttrs = NIL;
2677 : List *remote_exprs;
2678 195 : List *params_list = NIL;
2679 195 : List *returningList = NIL;
2680 195 : List *retrieved_attrs = NIL;
2681 :
2682 : /*
2683 : * Decide whether it is safe to modify a foreign table directly.
2684 : */
2685 :
2686 : /*
2687 : * The table modification must be an UPDATE or DELETE.
2688 : */
2689 195 : if (operation != CMD_UPDATE && operation != CMD_DELETE)
2690 64 : return false;
2691 :
2692 : /*
2693 : * Try to locate the ForeignScan subplan that's scanning resultRelation.
2694 : */
2695 131 : fscan = find_modifytable_subplan(root, plan, resultRelation, subplan_index);
2696 131 : if (!fscan)
2697 17 : return false;
2698 :
2699 : /*
2700 : * It's unsafe to modify a foreign table directly if there are any quals
2701 : * that should be evaluated locally.
2702 : */
2703 114 : if (fscan->scan.plan.qual != NIL)
2704 5 : return false;
2705 :
2706 : /* Safe to fetch data about the target foreign rel */
2707 109 : if (fscan->scan.scanrelid == 0)
2708 : {
2709 10 : foreignrel = find_join_rel(root, fscan->fs_relids);
2710 : /* We should have a rel for this foreign join. */
2711 : Assert(foreignrel);
2712 : }
2713 : else
2714 99 : foreignrel = root->simple_rel_array[resultRelation];
2715 109 : rte = root->simple_rte_array[resultRelation];
2716 109 : fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
2717 :
2718 : /*
2719 : * It's unsafe to update a foreign table directly, if any expressions to
2720 : * assign to the target columns are unsafe to evaluate remotely.
2721 : */
2722 109 : if (operation == CMD_UPDATE)
2723 : {
2724 : ListCell *lc,
2725 : *lc2;
2726 :
2727 : /*
2728 : * The expressions of concern are the first N columns of the processed
2729 : * targetlist, where N is the length of the rel's update_colnos.
2730 : */
2731 50 : get_translated_update_targetlist(root, resultRelation,
2732 : &processed_tlist, &targetAttrs);
2733 103 : forboth(lc, processed_tlist, lc2, targetAttrs)
2734 : {
2735 58 : TargetEntry *tle = lfirst_node(TargetEntry, lc);
2736 58 : AttrNumber attno = lfirst_int(lc2);
2737 :
2738 : /* update's new-value expressions shouldn't be resjunk */
2739 : Assert(!tle->resjunk);
2740 :
2741 58 : if (attno <= InvalidAttrNumber) /* shouldn't happen */
2742 0 : elog(ERROR, "system-column update is not supported");
2743 :
2744 58 : if (!is_foreign_expr(root, foreignrel, (Expr *) tle->expr))
2745 5 : return false;
2746 : }
2747 : }
2748 :
2749 : /*
2750 : * Ok, rewrite subplan so as to modify the foreign table directly.
2751 : */
2752 104 : initStringInfo(&sql);
2753 :
2754 : /*
2755 : * Core code already has some lock on each rel being planned, so we can
2756 : * use NoLock here.
2757 : */
2758 104 : rel = table_open(rte->relid, NoLock);
2759 :
2760 : /*
2761 : * Recall the qual clauses that must be evaluated remotely. (These are
2762 : * bare clauses not RestrictInfos, but deparse.c's appendConditions()
2763 : * doesn't care.)
2764 : */
2765 104 : remote_exprs = fpinfo->final_remote_exprs;
2766 :
2767 : /*
2768 : * Extract the relevant RETURNING list if any.
2769 : */
2770 104 : if (plan->returningLists)
2771 : {
2772 35 : returningList = (List *) list_nth(plan->returningLists, subplan_index);
2773 :
2774 : /*
2775 : * When performing an UPDATE/DELETE .. RETURNING on a join directly,
2776 : * we fetch from the foreign server any Vars specified in RETURNING
2777 : * that refer not only to the target relation but to non-target
2778 : * relations. So we'll deparse them into the RETURNING clause of the
2779 : * remote query; use a targetlist consisting of them instead, which
2780 : * will be adjusted to be new fdw_scan_tlist of the foreign-scan plan
2781 : * node below.
2782 : */
2783 35 : if (fscan->scan.scanrelid == 0)
2784 4 : returningList = build_remote_returning(resultRelation, rel,
2785 : returningList);
2786 : }
2787 :
2788 : /*
2789 : * Construct the SQL command string.
2790 : */
2791 104 : switch (operation)
2792 : {
2793 45 : case CMD_UPDATE:
2794 45 : deparseDirectUpdateSql(&sql, root, resultRelation, rel,
2795 : foreignrel,
2796 : processed_tlist,
2797 : targetAttrs,
2798 : remote_exprs, ¶ms_list,
2799 : returningList, &retrieved_attrs);
2800 45 : break;
2801 59 : case CMD_DELETE:
2802 59 : deparseDirectDeleteSql(&sql, root, resultRelation, rel,
2803 : foreignrel,
2804 : remote_exprs, ¶ms_list,
2805 : returningList, &retrieved_attrs);
2806 59 : break;
2807 0 : default:
2808 0 : elog(ERROR, "unexpected operation: %d", (int) operation);
2809 : break;
2810 : }
2811 :
2812 : /*
2813 : * Update the operation and target relation info.
2814 : */
2815 104 : fscan->operation = operation;
2816 104 : fscan->resultRelation = resultRelation;
2817 :
2818 : /*
2819 : * Update the fdw_exprs list that will be available to the executor.
2820 : */
2821 104 : fscan->fdw_exprs = params_list;
2822 :
2823 : /*
2824 : * Update the fdw_private list that will be available to the executor.
2825 : * Items in the list must match enum FdwDirectModifyPrivateIndex, above.
2826 : */
2827 104 : fscan->fdw_private = list_make4(makeString(sql.data),
2828 : makeBoolean((retrieved_attrs != NIL)),
2829 : retrieved_attrs,
2830 : makeBoolean(plan->canSetTag));
2831 :
2832 : /*
2833 : * Update the foreign-join-related fields.
2834 : */
2835 104 : if (fscan->scan.scanrelid == 0)
2836 : {
2837 : /* No need for the outer subplan. */
2838 8 : fscan->scan.plan.lefttree = NULL;
2839 :
2840 : /* Build new fdw_scan_tlist if UPDATE/DELETE .. RETURNING. */
2841 8 : if (returningList)
2842 2 : rebuild_fdw_scan_tlist(fscan, returningList);
2843 : }
2844 :
2845 : /*
2846 : * Finally, unset the async-capable flag if it is set, as we currently
2847 : * don't support asynchronous execution of direct modifications.
2848 : */
2849 104 : if (fscan->scan.plan.async_capable)
2850 8 : fscan->scan.plan.async_capable = false;
2851 :
2852 104 : table_close(rel, NoLock);
2853 104 : return true;
2854 : }
2855 :
2856 : /*
2857 : * postgresBeginDirectModify
2858 : * Prepare a direct foreign table modification
2859 : */
2860 : static void
2861 104 : postgresBeginDirectModify(ForeignScanState *node, int eflags)
2862 : {
2863 104 : ForeignScan *fsplan = (ForeignScan *) node->ss.ps.plan;
2864 104 : EState *estate = node->ss.ps.state;
2865 : PgFdwDirectModifyState *dmstate;
2866 : Index rtindex;
2867 : Oid userid;
2868 : ForeignTable *table;
2869 : UserMapping *user;
2870 : int numParams;
2871 :
2872 : /*
2873 : * Do nothing in EXPLAIN (no ANALYZE) case. node->fdw_state stays NULL.
2874 : */
2875 104 : if (eflags & EXEC_FLAG_EXPLAIN_ONLY)
2876 32 : return;
2877 :
2878 : /*
2879 : * We'll save private state in node->fdw_state.
2880 : */
2881 72 : dmstate = palloc0_object(PgFdwDirectModifyState);
2882 72 : node->fdw_state = dmstate;
2883 :
2884 : /*
2885 : * Identify which user to do the remote access as. This should match what
2886 : * ExecCheckPermissions() does.
2887 : */
2888 72 : userid = OidIsValid(fsplan->checkAsUser) ? fsplan->checkAsUser : GetUserId();
2889 :
2890 : /* Get info about foreign table. */
2891 72 : rtindex = node->resultRelInfo->ri_RangeTableIndex;
2892 72 : if (fsplan->scan.scanrelid == 0)
2893 4 : dmstate->rel = ExecOpenScanRelation(estate, rtindex, eflags);
2894 : else
2895 68 : dmstate->rel = node->ss.ss_currentRelation;
2896 72 : table = GetForeignTable(RelationGetRelid(dmstate->rel));
2897 72 : user = GetUserMapping(userid, table->serverid);
2898 :
2899 : /*
2900 : * Get connection to the foreign server. Connection manager will
2901 : * establish new connection if necessary.
2902 : */
2903 72 : dmstate->conn = GetConnection(user, false, &dmstate->conn_state);
2904 :
2905 : /* Update the foreign-join-related fields. */
2906 72 : if (fsplan->scan.scanrelid == 0)
2907 : {
2908 : /* Save info about foreign table. */
2909 4 : dmstate->resultRel = dmstate->rel;
2910 :
2911 : /*
2912 : * Set dmstate->rel to NULL to teach get_returning_data() and
2913 : * make_tuple_from_result_row() that columns fetched from the remote
2914 : * server are described by fdw_scan_tlist of the foreign-scan plan
2915 : * node, not the tuple descriptor for the target relation.
2916 : */
2917 4 : dmstate->rel = NULL;
2918 : }
2919 :
2920 : /* Initialize state variable */
2921 72 : dmstate->num_tuples = -1; /* -1 means not set yet */
2922 :
2923 : /* Get private info created by planner functions. */
2924 72 : dmstate->query = strVal(list_nth(fsplan->fdw_private,
2925 : FdwDirectModifyPrivateUpdateSql));
2926 72 : dmstate->has_returning = boolVal(list_nth(fsplan->fdw_private,
2927 : FdwDirectModifyPrivateHasReturning));
2928 72 : dmstate->retrieved_attrs = (List *) list_nth(fsplan->fdw_private,
2929 : FdwDirectModifyPrivateRetrievedAttrs);
2930 72 : dmstate->set_processed = boolVal(list_nth(fsplan->fdw_private,
2931 : FdwDirectModifyPrivateSetProcessed));
2932 :
2933 : /* Create context for per-tuple temp workspace. */
2934 72 : dmstate->temp_cxt = AllocSetContextCreate(estate->es_query_cxt,
2935 : "postgres_fdw temporary data",
2936 : ALLOCSET_SMALL_SIZES);
2937 :
2938 : /* Prepare for input conversion of RETURNING results. */
2939 72 : if (dmstate->has_returning)
2940 : {
2941 : TupleDesc tupdesc;
2942 :
2943 16 : if (fsplan->scan.scanrelid == 0)
2944 1 : tupdesc = get_tupdesc_for_join_scan_tuples(node);
2945 : else
2946 15 : tupdesc = RelationGetDescr(dmstate->rel);
2947 :
2948 16 : dmstate->attinmeta = TupleDescGetAttInMetadata(tupdesc);
2949 :
2950 : /*
2951 : * When performing an UPDATE/DELETE .. RETURNING on a join directly,
2952 : * initialize a filter to extract an updated/deleted tuple from a scan
2953 : * tuple.
2954 : */
2955 16 : if (fsplan->scan.scanrelid == 0)
2956 1 : init_returning_filter(dmstate, fsplan->fdw_scan_tlist, rtindex);
2957 : }
2958 :
2959 : /*
2960 : * Prepare for processing of parameters used in remote query, if any.
2961 : */
2962 72 : numParams = list_length(fsplan->fdw_exprs);
2963 72 : dmstate->numParams = numParams;
2964 72 : if (numParams > 0)
2965 0 : prepare_query_params((PlanState *) node,
2966 : fsplan->fdw_exprs,
2967 : numParams,
2968 : &dmstate->param_flinfo,
2969 : &dmstate->param_exprs,
2970 : &dmstate->param_values);
2971 : }
2972 :
2973 : /*
2974 : * postgresIterateDirectModify
2975 : * Execute a direct foreign table modification
2976 : */
2977 : static TupleTableSlot *
2978 418 : postgresIterateDirectModify(ForeignScanState *node)
2979 : {
2980 418 : PgFdwDirectModifyState *dmstate = (PgFdwDirectModifyState *) node->fdw_state;
2981 418 : EState *estate = node->ss.ps.state;
2982 418 : ResultRelInfo *resultRelInfo = node->resultRelInfo;
2983 :
2984 : /*
2985 : * If this is the first call after Begin, execute the statement.
2986 : */
2987 418 : if (dmstate->num_tuples == -1)
2988 71 : execute_dml_stmt(node);
2989 :
2990 : /*
2991 : * If the local query doesn't specify RETURNING, just clear tuple slot.
2992 : */
2993 414 : if (!resultRelInfo->ri_projectReturning)
2994 : {
2995 50 : TupleTableSlot *slot = node->ss.ss_ScanTupleSlot;
2996 50 : NodeInstrumentation *instr = node->ss.ps.instrument;
2997 :
2998 : Assert(!dmstate->has_returning);
2999 :
3000 : /* Increment the command es_processed count if necessary. */
3001 50 : if (dmstate->set_processed)
3002 50 : estate->es_processed += dmstate->num_tuples;
3003 :
3004 : /* Increment the tuple count for EXPLAIN ANALYZE if necessary. */
3005 50 : if (instr)
3006 0 : instr->tuplecount += dmstate->num_tuples;
3007 :
3008 50 : return ExecClearTuple(slot);
3009 : }
3010 :
3011 : /*
3012 : * Get the next RETURNING tuple.
3013 : */
3014 364 : return get_returning_data(node);
3015 : }
3016 :
3017 : /*
3018 : * postgresEndDirectModify
3019 : * Finish a direct foreign table modification
3020 : */
3021 : static void
3022 96 : postgresEndDirectModify(ForeignScanState *node)
3023 : {
3024 96 : PgFdwDirectModifyState *dmstate = (PgFdwDirectModifyState *) node->fdw_state;
3025 :
3026 : /* if dmstate is NULL, we are in EXPLAIN; nothing to do */
3027 96 : if (dmstate == NULL)
3028 32 : return;
3029 :
3030 : /* Release PGresult */
3031 64 : PQclear(dmstate->result);
3032 :
3033 : /* Release remote connection */
3034 64 : ReleaseConnection(dmstate->conn);
3035 64 : dmstate->conn = NULL;
3036 :
3037 : /* MemoryContext will be deleted automatically. */
3038 : }
3039 :
3040 : /*
3041 : * postgresExplainForeignScan
3042 : * Produce extra output for EXPLAIN of a ForeignScan on a foreign table
3043 : */
3044 : static void
3045 396 : postgresExplainForeignScan(ForeignScanState *node, ExplainState *es)
3046 : {
3047 396 : ForeignScan *plan = castNode(ForeignScan, node->ss.ps.plan);
3048 396 : List *fdw_private = plan->fdw_private;
3049 :
3050 : /*
3051 : * Identify foreign scans that are really joins or upper relations. The
3052 : * input looks something like "(1) LEFT JOIN (2)", and we must replace the
3053 : * digit string(s), which are RT indexes, with the correct relation names.
3054 : * We do that here, not when the plan is created, because we can't know
3055 : * what aliases ruleutils.c will assign at plan creation time.
3056 : */
3057 396 : if (list_length(fdw_private) > FdwScanPrivateRelations)
3058 : {
3059 : StringInfoData relations;
3060 : char *rawrelations;
3061 : char *ptr;
3062 : int minrti,
3063 : rtoffset;
3064 :
3065 123 : rawrelations = strVal(list_nth(fdw_private, FdwScanPrivateRelations));
3066 :
3067 : /*
3068 : * A difficulty with using a string representation of RT indexes is
3069 : * that setrefs.c won't update the string when flattening the
3070 : * rangetable. To find out what rtoffset was applied, identify the
3071 : * minimum RT index appearing in the string and compare it to the
3072 : * minimum member of plan->fs_base_relids. (We expect all the relids
3073 : * in the join will have been offset by the same amount; the Asserts
3074 : * below should catch it if that ever changes.)
3075 : */
3076 123 : minrti = INT_MAX;
3077 123 : ptr = rawrelations;
3078 2915 : while (*ptr)
3079 : {
3080 2792 : if (isdigit((unsigned char) *ptr))
3081 : {
3082 243 : int rti = strtol(ptr, &ptr, 10);
3083 :
3084 243 : if (rti < minrti)
3085 135 : minrti = rti;
3086 : }
3087 : else
3088 2549 : ptr++;
3089 : }
3090 123 : rtoffset = bms_next_member(plan->fs_base_relids, -1) - minrti;
3091 :
3092 : /* Now we can translate the string */
3093 123 : initStringInfo(&relations);
3094 123 : ptr = rawrelations;
3095 2915 : while (*ptr)
3096 : {
3097 2792 : if (isdigit((unsigned char) *ptr))
3098 : {
3099 243 : int rti = strtol(ptr, &ptr, 10);
3100 : RangeTblEntry *rte;
3101 : char *relname;
3102 : char *refname;
3103 :
3104 243 : rti += rtoffset;
3105 : Assert(bms_is_member(rti, plan->fs_base_relids));
3106 243 : rte = rt_fetch(rti, es->rtable);
3107 : Assert(rte->rtekind == RTE_RELATION);
3108 : /* This logic should agree with explain.c's ExplainTargetRel */
3109 243 : relname = get_rel_name(rte->relid);
3110 243 : if (es->verbose)
3111 : {
3112 : char *namespace;
3113 :
3114 230 : namespace = get_namespace_name_or_temp(get_rel_namespace(rte->relid));
3115 230 : appendStringInfo(&relations, "%s.%s",
3116 : quote_identifier(namespace),
3117 : quote_identifier(relname));
3118 : }
3119 : else
3120 13 : appendStringInfoString(&relations,
3121 : quote_identifier(relname));
3122 243 : refname = (char *) list_nth(es->rtable_names, rti - 1);
3123 243 : if (refname == NULL)
3124 0 : refname = rte->eref->aliasname;
3125 243 : if (strcmp(refname, relname) != 0)
3126 149 : appendStringInfo(&relations, " %s",
3127 : quote_identifier(refname));
3128 : }
3129 : else
3130 2549 : appendStringInfoChar(&relations, *ptr++);
3131 : }
3132 123 : ExplainPropertyText("Relations", relations.data, es);
3133 : }
3134 :
3135 : /*
3136 : * Add remote query, when VERBOSE option is specified.
3137 : */
3138 396 : if (es->verbose)
3139 : {
3140 : char *sql;
3141 :
3142 360 : sql = strVal(list_nth(fdw_private, FdwScanPrivateSelectSql));
3143 360 : ExplainPropertyText("Remote SQL", sql, es);
3144 : }
3145 396 : }
3146 :
3147 : /*
3148 : * postgresExplainForeignModify
3149 : * Produce extra output for EXPLAIN of a ModifyTable on a foreign table
3150 : */
3151 : static void
3152 46 : postgresExplainForeignModify(ModifyTableState *mtstate,
3153 : ResultRelInfo *rinfo,
3154 : List *fdw_private,
3155 : int subplan_index,
3156 : ExplainState *es)
3157 : {
3158 46 : if (es->verbose)
3159 : {
3160 46 : char *sql = strVal(list_nth(fdw_private,
3161 : FdwModifyPrivateUpdateSql));
3162 :
3163 46 : ExplainPropertyText("Remote SQL", sql, es);
3164 :
3165 : /*
3166 : * For INSERT we should always have batch size >= 1, but UPDATE and
3167 : * DELETE don't support batching so don't show the property.
3168 : */
3169 46 : if (rinfo->ri_BatchSize > 0)
3170 13 : ExplainPropertyInteger("Batch Size", NULL, rinfo->ri_BatchSize, es);
3171 : }
3172 46 : }
3173 :
3174 : /*
3175 : * postgresExplainDirectModify
3176 : * Produce extra output for EXPLAIN of a ForeignScan that modifies a
3177 : * foreign table directly
3178 : */
3179 : static void
3180 32 : postgresExplainDirectModify(ForeignScanState *node, ExplainState *es)
3181 : {
3182 : List *fdw_private;
3183 : char *sql;
3184 :
3185 32 : if (es->verbose)
3186 : {
3187 32 : fdw_private = ((ForeignScan *) node->ss.ps.plan)->fdw_private;
3188 32 : sql = strVal(list_nth(fdw_private, FdwDirectModifyPrivateUpdateSql));
3189 32 : ExplainPropertyText("Remote SQL", sql, es);
3190 : }
3191 32 : }
3192 :
3193 : /*
3194 : * postgresExecForeignTruncate
3195 : * Truncate one or more foreign tables
3196 : */
3197 : static void
3198 15 : postgresExecForeignTruncate(List *rels,
3199 : DropBehavior behavior,
3200 : bool restart_seqs)
3201 : {
3202 15 : Oid serverid = InvalidOid;
3203 15 : UserMapping *user = NULL;
3204 15 : PGconn *conn = NULL;
3205 : StringInfoData sql;
3206 : ListCell *lc;
3207 15 : bool server_truncatable = true;
3208 :
3209 : /*
3210 : * By default, all postgres_fdw foreign tables are assumed truncatable.
3211 : * This can be overridden by a per-server setting, which in turn can be
3212 : * overridden by a per-table setting.
3213 : */
3214 29 : foreach(lc, rels)
3215 : {
3216 17 : ForeignServer *server = NULL;
3217 17 : Relation rel = lfirst(lc);
3218 17 : ForeignTable *table = GetForeignTable(RelationGetRelid(rel));
3219 : ListCell *cell;
3220 : bool truncatable;
3221 :
3222 : /*
3223 : * First time through, determine whether the foreign server allows
3224 : * truncates. Since all specified foreign tables are assumed to belong
3225 : * to the same foreign server, this result can be used for other
3226 : * foreign tables.
3227 : */
3228 17 : if (!OidIsValid(serverid))
3229 : {
3230 15 : serverid = table->serverid;
3231 15 : server = GetForeignServer(serverid);
3232 :
3233 60 : foreach(cell, server->options)
3234 : {
3235 48 : DefElem *defel = (DefElem *) lfirst(cell);
3236 :
3237 48 : if (strcmp(defel->defname, "truncatable") == 0)
3238 : {
3239 3 : server_truncatable = defGetBoolean(defel);
3240 3 : break;
3241 : }
3242 : }
3243 : }
3244 :
3245 : /*
3246 : * Confirm that all specified foreign tables belong to the same
3247 : * foreign server.
3248 : */
3249 : Assert(table->serverid == serverid);
3250 :
3251 : /* Determine whether this foreign table allows truncations */
3252 17 : truncatable = server_truncatable;
3253 34 : foreach(cell, table->options)
3254 : {
3255 24 : DefElem *defel = (DefElem *) lfirst(cell);
3256 :
3257 24 : if (strcmp(defel->defname, "truncatable") == 0)
3258 : {
3259 7 : truncatable = defGetBoolean(defel);
3260 7 : break;
3261 : }
3262 : }
3263 :
3264 17 : if (!truncatable)
3265 3 : ereport(ERROR,
3266 : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
3267 : errmsg("foreign table \"%s\" does not allow truncates",
3268 : RelationGetRelationName(rel))));
3269 : }
3270 : Assert(OidIsValid(serverid));
3271 :
3272 : /*
3273 : * Get connection to the foreign server. Connection manager will
3274 : * establish new connection if necessary.
3275 : */
3276 12 : user = GetUserMapping(GetUserId(), serverid);
3277 12 : conn = GetConnection(user, false, NULL);
3278 :
3279 : /* Construct the TRUNCATE command string */
3280 12 : initStringInfo(&sql);
3281 12 : deparseTruncateSql(&sql, rels, behavior, restart_seqs);
3282 :
3283 : /* Issue the TRUNCATE command to remote server */
3284 12 : do_sql_command(conn, sql.data);
3285 :
3286 11 : pfree(sql.data);
3287 11 : }
3288 :
3289 : /*
3290 : * estimate_path_cost_size
3291 : * Get cost and size estimates for a foreign scan on given foreign relation
3292 : * either a base relation or a join between foreign relations or an upper
3293 : * relation containing foreign relations.
3294 : *
3295 : * param_join_conds are the parameterization clauses with outer relations.
3296 : * pathkeys specify the expected sort order if any for given path being costed.
3297 : * fpextra specifies additional post-scan/join-processing steps such as the
3298 : * final sort and the LIMIT restriction.
3299 : *
3300 : * The function returns the cost and size estimates in p_rows, p_width,
3301 : * p_disabled_nodes, p_startup_cost and p_total_cost variables.
3302 : */
3303 : static void
3304 2746 : estimate_path_cost_size(PlannerInfo *root,
3305 : RelOptInfo *foreignrel,
3306 : List *param_join_conds,
3307 : List *pathkeys,
3308 : PgFdwPathExtraData *fpextra,
3309 : double *p_rows, int *p_width,
3310 : int *p_disabled_nodes,
3311 : Cost *p_startup_cost, Cost *p_total_cost)
3312 : {
3313 2746 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
3314 : double rows;
3315 : double retrieved_rows;
3316 : int width;
3317 2746 : int disabled_nodes = 0;
3318 : Cost startup_cost;
3319 : Cost total_cost;
3320 :
3321 : /* Make sure the core code has set up the relation's reltarget */
3322 : Assert(foreignrel->reltarget);
3323 :
3324 : /*
3325 : * If the table or the server is configured to use remote estimates,
3326 : * connect to the foreign server and execute EXPLAIN to estimate the
3327 : * number of rows selected by the restriction+join clauses. Otherwise,
3328 : * estimate rows using whatever statistics we have locally, in a way
3329 : * similar to ordinary tables.
3330 : */
3331 2746 : if (fpinfo->use_remote_estimate)
3332 : {
3333 : List *remote_param_join_conds;
3334 : List *local_param_join_conds;
3335 : StringInfoData sql;
3336 : PGconn *conn;
3337 : Selectivity local_sel;
3338 : QualCost local_cost;
3339 1319 : List *fdw_scan_tlist = NIL;
3340 : List *remote_conds;
3341 :
3342 : /* Required only to be passed to deparseSelectStmtForRel */
3343 : List *retrieved_attrs;
3344 :
3345 : /*
3346 : * param_join_conds might contain both clauses that are safe to send
3347 : * across, and clauses that aren't.
3348 : */
3349 1319 : classifyConditions(root, foreignrel, param_join_conds,
3350 : &remote_param_join_conds, &local_param_join_conds);
3351 :
3352 : /* Build the list of columns to be fetched from the foreign server. */
3353 1319 : if (IS_JOIN_REL(foreignrel) || IS_UPPER_REL(foreignrel))
3354 527 : fdw_scan_tlist = build_tlist_to_deparse(foreignrel);
3355 : else
3356 792 : fdw_scan_tlist = NIL;
3357 :
3358 : /*
3359 : * The complete list of remote conditions includes everything from
3360 : * baserestrictinfo plus any extra join_conds relevant to this
3361 : * particular path.
3362 : */
3363 1319 : remote_conds = list_concat(remote_param_join_conds,
3364 1319 : fpinfo->remote_conds);
3365 :
3366 : /*
3367 : * Construct EXPLAIN query including the desired SELECT, FROM, and
3368 : * WHERE clauses. Params and other-relation Vars are replaced by dummy
3369 : * values, so don't request params_list.
3370 : */
3371 1319 : initStringInfo(&sql);
3372 1319 : appendStringInfoString(&sql, "EXPLAIN ");
3373 1401 : deparseSelectStmtForRel(&sql, root, foreignrel, fdw_scan_tlist,
3374 : remote_conds, pathkeys,
3375 41 : fpextra ? fpextra->has_final_sort : false,
3376 41 : fpextra ? fpextra->has_limit : false,
3377 : false, &retrieved_attrs, NULL);
3378 :
3379 : /* Get the remote estimate */
3380 1319 : conn = GetConnection(fpinfo->user, false, NULL);
3381 1319 : get_remote_estimate(sql.data, conn, &rows, &width,
3382 : &startup_cost, &total_cost);
3383 1319 : ReleaseConnection(conn);
3384 :
3385 1319 : retrieved_rows = rows;
3386 :
3387 : /* Factor in the selectivity of the locally-checked quals */
3388 1319 : local_sel = clauselist_selectivity(root,
3389 : local_param_join_conds,
3390 1319 : foreignrel->relid,
3391 : JOIN_INNER,
3392 : NULL);
3393 1319 : local_sel *= fpinfo->local_conds_sel;
3394 :
3395 1319 : rows = clamp_row_est(rows * local_sel);
3396 :
3397 : /* Add in the eval cost of the locally-checked quals */
3398 1319 : startup_cost += fpinfo->local_conds_cost.startup;
3399 1319 : total_cost += fpinfo->local_conds_cost.per_tuple * retrieved_rows;
3400 1319 : cost_qual_eval(&local_cost, local_param_join_conds, root);
3401 1319 : startup_cost += local_cost.startup;
3402 1319 : total_cost += local_cost.per_tuple * retrieved_rows;
3403 :
3404 : /*
3405 : * Add in tlist eval cost for each output row. In case of an
3406 : * aggregate, some of the tlist expressions such as grouping
3407 : * expressions will be evaluated remotely, so adjust the costs.
3408 : */
3409 1319 : startup_cost += foreignrel->reltarget->cost.startup;
3410 1319 : total_cost += foreignrel->reltarget->cost.startup;
3411 1319 : total_cost += foreignrel->reltarget->cost.per_tuple * rows;
3412 1319 : if (IS_UPPER_REL(foreignrel))
3413 : {
3414 : QualCost tlist_cost;
3415 :
3416 40 : cost_qual_eval(&tlist_cost, fdw_scan_tlist, root);
3417 40 : startup_cost -= tlist_cost.startup;
3418 40 : total_cost -= tlist_cost.startup;
3419 40 : total_cost -= tlist_cost.per_tuple * rows;
3420 : }
3421 : }
3422 : else
3423 : {
3424 1427 : Cost run_cost = 0;
3425 :
3426 : /*
3427 : * We don't support join conditions in this mode (hence, no
3428 : * parameterized paths can be made).
3429 : */
3430 : Assert(param_join_conds == NIL);
3431 :
3432 : /*
3433 : * We will come here again and again with different set of pathkeys or
3434 : * additional post-scan/join-processing steps that caller wants to
3435 : * cost. We don't need to calculate the cost/size estimates for the
3436 : * underlying scan, join, or grouping each time. Instead, use those
3437 : * estimates if we have cached them already.
3438 : */
3439 1427 : if (fpinfo->rel_startup_cost >= 0 && fpinfo->rel_total_cost >= 0)
3440 : {
3441 : Assert(fpinfo->retrieved_rows >= 0);
3442 :
3443 314 : rows = fpinfo->rows;
3444 314 : retrieved_rows = fpinfo->retrieved_rows;
3445 314 : width = fpinfo->width;
3446 314 : startup_cost = fpinfo->rel_startup_cost;
3447 314 : run_cost = fpinfo->rel_total_cost - fpinfo->rel_startup_cost;
3448 :
3449 : /*
3450 : * If we estimate the costs of a foreign scan or a foreign join
3451 : * with additional post-scan/join-processing steps, the scan or
3452 : * join costs obtained from the cache wouldn't yet contain the
3453 : * eval costs for the final scan/join target, which would've been
3454 : * updated by apply_scanjoin_target_to_paths(); add the eval costs
3455 : * now.
3456 : */
3457 314 : if (fpextra && !IS_UPPER_REL(foreignrel))
3458 : {
3459 : /* Shouldn't get here unless we have LIMIT */
3460 : Assert(fpextra->has_limit);
3461 : Assert(foreignrel->reloptkind == RELOPT_BASEREL ||
3462 : foreignrel->reloptkind == RELOPT_JOINREL);
3463 90 : startup_cost += foreignrel->reltarget->cost.startup;
3464 90 : run_cost += foreignrel->reltarget->cost.per_tuple * rows;
3465 : }
3466 : }
3467 1113 : else if (IS_JOIN_REL(foreignrel))
3468 112 : {
3469 : PgFdwRelationInfo *fpinfo_i;
3470 : PgFdwRelationInfo *fpinfo_o;
3471 : QualCost join_cost;
3472 : QualCost remote_conds_cost;
3473 : double nrows;
3474 :
3475 : /* Use rows/width estimates made by the core code. */
3476 112 : rows = foreignrel->rows;
3477 112 : width = foreignrel->reltarget->width;
3478 :
3479 : /* For join we expect inner and outer relations set */
3480 : Assert(fpinfo->innerrel && fpinfo->outerrel);
3481 :
3482 112 : fpinfo_i = (PgFdwRelationInfo *) fpinfo->innerrel->fdw_private;
3483 112 : fpinfo_o = (PgFdwRelationInfo *) fpinfo->outerrel->fdw_private;
3484 :
3485 : /* Estimate of number of rows in cross product */
3486 112 : nrows = fpinfo_i->rows * fpinfo_o->rows;
3487 :
3488 : /*
3489 : * Back into an estimate of the number of retrieved rows. Just in
3490 : * case this is nuts, clamp to at most nrows.
3491 : */
3492 112 : retrieved_rows = clamp_row_est(rows / fpinfo->local_conds_sel);
3493 112 : retrieved_rows = Min(retrieved_rows, nrows);
3494 :
3495 : /*
3496 : * The cost of foreign join is estimated as cost of generating
3497 : * rows for the joining relations + cost for applying quals on the
3498 : * rows.
3499 : */
3500 :
3501 : /*
3502 : * Calculate the cost of clauses pushed down to the foreign server
3503 : */
3504 112 : cost_qual_eval(&remote_conds_cost, fpinfo->remote_conds, root);
3505 : /* Calculate the cost of applying join clauses */
3506 112 : cost_qual_eval(&join_cost, fpinfo->joinclauses, root);
3507 :
3508 : /*
3509 : * Startup cost includes startup cost of joining relations and the
3510 : * startup cost for join and other clauses. We do not include the
3511 : * startup cost specific to join strategy (e.g. setting up hash
3512 : * tables) since we do not know what strategy the foreign server
3513 : * is going to use.
3514 : */
3515 112 : startup_cost = fpinfo_i->rel_startup_cost + fpinfo_o->rel_startup_cost;
3516 112 : startup_cost += join_cost.startup;
3517 112 : startup_cost += remote_conds_cost.startup;
3518 112 : startup_cost += fpinfo->local_conds_cost.startup;
3519 :
3520 : /*
3521 : * Run time cost includes:
3522 : *
3523 : * 1. Run time cost (total_cost - startup_cost) of relations being
3524 : * joined
3525 : *
3526 : * 2. Run time cost of applying join clauses on the cross product
3527 : * of the joining relations.
3528 : *
3529 : * 3. Run time cost of applying pushed down other clauses on the
3530 : * result of join
3531 : *
3532 : * 4. Run time cost of applying nonpushable other clauses locally
3533 : * on the result fetched from the foreign server.
3534 : */
3535 112 : run_cost = fpinfo_i->rel_total_cost - fpinfo_i->rel_startup_cost;
3536 112 : run_cost += fpinfo_o->rel_total_cost - fpinfo_o->rel_startup_cost;
3537 112 : run_cost += nrows * join_cost.per_tuple;
3538 112 : nrows = clamp_row_est(nrows * fpinfo->joinclause_sel);
3539 112 : run_cost += nrows * remote_conds_cost.per_tuple;
3540 112 : run_cost += fpinfo->local_conds_cost.per_tuple * retrieved_rows;
3541 :
3542 : /* Add in tlist eval cost for each output row */
3543 112 : startup_cost += foreignrel->reltarget->cost.startup;
3544 112 : run_cost += foreignrel->reltarget->cost.per_tuple * rows;
3545 : }
3546 1001 : else if (IS_UPPER_REL(foreignrel))
3547 100 : {
3548 100 : RelOptInfo *outerrel = fpinfo->outerrel;
3549 : PgFdwRelationInfo *ofpinfo;
3550 100 : AggClauseCosts aggcosts = {0};
3551 : double input_rows;
3552 : int numGroupCols;
3553 100 : double numGroups = 1;
3554 :
3555 : /* The upper relation should have its outer relation set */
3556 : Assert(outerrel);
3557 : /* and that outer relation should have its reltarget set */
3558 : Assert(outerrel->reltarget);
3559 :
3560 : /*
3561 : * This cost model is mixture of costing done for sorted and
3562 : * hashed aggregates in cost_agg(). We are not sure which
3563 : * strategy will be considered at remote side, thus for
3564 : * simplicity, we put all startup related costs in startup_cost
3565 : * and all finalization and run cost are added in total_cost.
3566 : */
3567 :
3568 100 : ofpinfo = (PgFdwRelationInfo *) outerrel->fdw_private;
3569 :
3570 : /* Get rows from input rel */
3571 100 : input_rows = ofpinfo->rows;
3572 :
3573 : /* Collect statistics about aggregates for estimating costs. */
3574 100 : if (root->parse->hasAggs)
3575 : {
3576 96 : get_agg_clause_costs(root, AGGSPLIT_SIMPLE, &aggcosts);
3577 : }
3578 :
3579 : /* Get number of grouping columns and possible number of groups */
3580 100 : numGroupCols = list_length(root->processed_groupClause);
3581 100 : numGroups = estimate_num_groups(root,
3582 : get_sortgrouplist_exprs(root->processed_groupClause,
3583 : fpinfo->grouped_tlist),
3584 : input_rows, NULL, NULL);
3585 :
3586 : /*
3587 : * Get the retrieved_rows and rows estimates. If there are HAVING
3588 : * quals, account for their selectivity.
3589 : */
3590 100 : if (root->hasHavingQual)
3591 : {
3592 : /* Factor in the selectivity of the remotely-checked quals */
3593 : retrieved_rows =
3594 14 : clamp_row_est(numGroups *
3595 14 : clauselist_selectivity(root,
3596 : fpinfo->remote_conds,
3597 : 0,
3598 : JOIN_INNER,
3599 : NULL));
3600 : /* Factor in the selectivity of the locally-checked quals */
3601 14 : rows = clamp_row_est(retrieved_rows * fpinfo->local_conds_sel);
3602 : }
3603 : else
3604 : {
3605 86 : rows = retrieved_rows = numGroups;
3606 : }
3607 :
3608 : /* Use width estimate made by the core code. */
3609 100 : width = foreignrel->reltarget->width;
3610 :
3611 : /*-----
3612 : * Startup cost includes:
3613 : * 1. Startup cost for underneath input relation, adjusted for
3614 : * tlist replacement by apply_scanjoin_target_to_paths()
3615 : * 2. Cost of performing aggregation, per cost_agg()
3616 : *-----
3617 : */
3618 100 : startup_cost = ofpinfo->rel_startup_cost;
3619 100 : startup_cost += outerrel->reltarget->cost.startup;
3620 100 : startup_cost += aggcosts.transCost.startup;
3621 100 : startup_cost += aggcosts.transCost.per_tuple * input_rows;
3622 100 : startup_cost += aggcosts.finalCost.startup;
3623 100 : startup_cost += (cpu_operator_cost * numGroupCols) * input_rows;
3624 :
3625 : /*-----
3626 : * Run time cost includes:
3627 : * 1. Run time cost of underneath input relation, adjusted for
3628 : * tlist replacement by apply_scanjoin_target_to_paths()
3629 : * 2. Run time cost of performing aggregation, per cost_agg()
3630 : *-----
3631 : */
3632 100 : run_cost = ofpinfo->rel_total_cost - ofpinfo->rel_startup_cost;
3633 100 : run_cost += outerrel->reltarget->cost.per_tuple * input_rows;
3634 100 : run_cost += aggcosts.finalCost.per_tuple * numGroups;
3635 100 : run_cost += cpu_tuple_cost * numGroups;
3636 :
3637 : /* Account for the eval cost of HAVING quals, if any */
3638 100 : if (root->hasHavingQual)
3639 : {
3640 : QualCost remote_cost;
3641 :
3642 : /* Add in the eval cost of the remotely-checked quals */
3643 14 : cost_qual_eval(&remote_cost, fpinfo->remote_conds, root);
3644 14 : startup_cost += remote_cost.startup;
3645 14 : run_cost += remote_cost.per_tuple * numGroups;
3646 : /* Add in the eval cost of the locally-checked quals */
3647 14 : startup_cost += fpinfo->local_conds_cost.startup;
3648 14 : run_cost += fpinfo->local_conds_cost.per_tuple * retrieved_rows;
3649 : }
3650 :
3651 : /* Add in tlist eval cost for each output row */
3652 100 : startup_cost += foreignrel->reltarget->cost.startup;
3653 100 : run_cost += foreignrel->reltarget->cost.per_tuple * rows;
3654 : }
3655 : else
3656 : {
3657 : Cost cpu_per_tuple;
3658 :
3659 : /* Use rows/width estimates made by set_baserel_size_estimates. */
3660 901 : rows = foreignrel->rows;
3661 901 : width = foreignrel->reltarget->width;
3662 :
3663 : /*
3664 : * Back into an estimate of the number of retrieved rows. Just in
3665 : * case this is nuts, clamp to at most foreignrel->tuples.
3666 : */
3667 901 : retrieved_rows = clamp_row_est(rows / fpinfo->local_conds_sel);
3668 901 : retrieved_rows = Min(retrieved_rows, foreignrel->tuples);
3669 :
3670 : /*
3671 : * Cost as though this were a seqscan, which is pessimistic. We
3672 : * effectively imagine the local_conds are being evaluated
3673 : * remotely, too.
3674 : */
3675 901 : startup_cost = 0;
3676 901 : run_cost = 0;
3677 901 : run_cost += seq_page_cost * foreignrel->pages;
3678 :
3679 901 : startup_cost += foreignrel->baserestrictcost.startup;
3680 901 : cpu_per_tuple = cpu_tuple_cost + foreignrel->baserestrictcost.per_tuple;
3681 901 : run_cost += cpu_per_tuple * foreignrel->tuples;
3682 :
3683 : /* Add in tlist eval cost for each output row */
3684 901 : startup_cost += foreignrel->reltarget->cost.startup;
3685 901 : run_cost += foreignrel->reltarget->cost.per_tuple * rows;
3686 : }
3687 :
3688 : /*
3689 : * Without remote estimates, we have no real way to estimate the cost
3690 : * of generating sorted output. It could be free if the query plan
3691 : * the remote side would have chosen generates properly-sorted output
3692 : * anyway, but in most cases it will cost something. Estimate a value
3693 : * high enough that we won't pick the sorted path when the ordering
3694 : * isn't locally useful, but low enough that we'll err on the side of
3695 : * pushing down the ORDER BY clause when it's useful to do so.
3696 : */
3697 1427 : if (pathkeys != NIL)
3698 : {
3699 258 : if (IS_UPPER_REL(foreignrel))
3700 : {
3701 : Assert(foreignrel->reloptkind == RELOPT_UPPER_REL &&
3702 : fpinfo->stage == UPPERREL_GROUP_AGG);
3703 :
3704 : /*
3705 : * We can only get here when this function is called from
3706 : * add_foreign_ordered_paths() or add_foreign_final_paths();
3707 : * in which cases, the passed-in fpextra should not be NULL.
3708 : */
3709 : Assert(fpextra);
3710 30 : adjust_foreign_grouping_path_cost(root, pathkeys,
3711 : retrieved_rows, width,
3712 : fpextra->limit_tuples,
3713 : &disabled_nodes,
3714 : &startup_cost, &run_cost);
3715 : }
3716 : else
3717 : {
3718 228 : startup_cost *= DEFAULT_FDW_SORT_MULTIPLIER;
3719 228 : run_cost *= DEFAULT_FDW_SORT_MULTIPLIER;
3720 : }
3721 : }
3722 :
3723 1427 : total_cost = startup_cost + run_cost;
3724 :
3725 : /* Adjust the cost estimates if we have LIMIT */
3726 1427 : if (fpextra && fpextra->has_limit)
3727 : {
3728 92 : adjust_limit_rows_costs(&rows, &startup_cost, &total_cost,
3729 : fpextra->offset_est, fpextra->count_est);
3730 92 : retrieved_rows = rows;
3731 : }
3732 : }
3733 :
3734 : /*
3735 : * If this includes the final sort step, the given target, which will be
3736 : * applied to the resulting path, might have different expressions from
3737 : * the foreignrel's reltarget (see make_sort_input_target()); adjust tlist
3738 : * eval costs.
3739 : */
3740 2746 : if (fpextra && fpextra->has_final_sort &&
3741 109 : fpextra->target != foreignrel->reltarget)
3742 : {
3743 6 : QualCost oldcost = foreignrel->reltarget->cost;
3744 6 : QualCost newcost = fpextra->target->cost;
3745 :
3746 6 : startup_cost += newcost.startup - oldcost.startup;
3747 6 : total_cost += newcost.startup - oldcost.startup;
3748 6 : total_cost += (newcost.per_tuple - oldcost.per_tuple) * rows;
3749 : }
3750 :
3751 : /*
3752 : * Cache the retrieved rows and cost estimates for scans, joins, or
3753 : * groupings without any parameterization, pathkeys, or additional
3754 : * post-scan/join-processing steps, before adding the costs for
3755 : * transferring data from the foreign server. These estimates are useful
3756 : * for costing remote joins involving this relation or costing other
3757 : * remote operations on this relation such as remote sorts and remote
3758 : * LIMIT restrictions, when the costs can not be obtained from the foreign
3759 : * server. This function will be called at least once for every foreign
3760 : * relation without any parameterization, pathkeys, or additional
3761 : * post-scan/join-processing steps.
3762 : */
3763 2746 : if (pathkeys == NIL && param_join_conds == NIL && fpextra == NULL)
3764 : {
3765 1679 : fpinfo->retrieved_rows = retrieved_rows;
3766 1679 : fpinfo->rel_startup_cost = startup_cost;
3767 1679 : fpinfo->rel_total_cost = total_cost;
3768 : }
3769 :
3770 : /*
3771 : * Add some additional cost factors to account for connection overhead
3772 : * (fdw_startup_cost), transferring data across the network
3773 : * (fdw_tuple_cost per retrieved row), and local manipulation of the data
3774 : * (cpu_tuple_cost per retrieved row).
3775 : */
3776 2746 : startup_cost += fpinfo->fdw_startup_cost;
3777 2746 : total_cost += fpinfo->fdw_startup_cost;
3778 2746 : total_cost += fpinfo->fdw_tuple_cost * retrieved_rows;
3779 2746 : total_cost += cpu_tuple_cost * retrieved_rows;
3780 :
3781 : /*
3782 : * If we have LIMIT, we should prefer performing the restriction remotely
3783 : * rather than locally, as the former avoids extra row fetches from the
3784 : * remote that the latter might cause. But since the core code doesn't
3785 : * account for such fetches when estimating the costs of the local
3786 : * restriction (see create_limit_path()), there would be no difference
3787 : * between the costs of the local restriction and the costs of the remote
3788 : * restriction estimated above if we don't use remote estimates (except
3789 : * for the case where the foreignrel is a grouping relation, the given
3790 : * pathkeys is not NIL, and the effects of a bounded sort for that rel is
3791 : * accounted for in costing the remote restriction). Tweak the costs of
3792 : * the remote restriction to ensure we'll prefer it if LIMIT is a useful
3793 : * one.
3794 : */
3795 2746 : if (!fpinfo->use_remote_estimate &&
3796 122 : fpextra && fpextra->has_limit &&
3797 92 : fpextra->limit_tuples > 0 &&
3798 92 : fpextra->limit_tuples < fpinfo->rows)
3799 : {
3800 : Assert(fpinfo->rows > 0);
3801 86 : total_cost -= (total_cost - startup_cost) * 0.05 *
3802 86 : (fpinfo->rows - fpextra->limit_tuples) / fpinfo->rows;
3803 : }
3804 :
3805 : /* Return results. */
3806 2746 : *p_rows = rows;
3807 2746 : *p_width = width;
3808 2746 : *p_disabled_nodes = disabled_nodes;
3809 2746 : *p_startup_cost = startup_cost;
3810 2746 : *p_total_cost = total_cost;
3811 2746 : }
3812 :
3813 : /*
3814 : * Estimate costs of executing a SQL statement remotely.
3815 : * The given "sql" must be an EXPLAIN command.
3816 : */
3817 : static void
3818 1319 : get_remote_estimate(const char *sql, PGconn *conn,
3819 : double *rows, int *width,
3820 : Cost *startup_cost, Cost *total_cost)
3821 : {
3822 : PGresult *res;
3823 : char *line;
3824 : char *p;
3825 : int n;
3826 :
3827 : /*
3828 : * Execute EXPLAIN remotely.
3829 : */
3830 1319 : res = pgfdw_exec_query(conn, sql, NULL);
3831 1319 : if (PQresultStatus(res) != PGRES_TUPLES_OK)
3832 0 : pgfdw_report_error(res, conn, sql);
3833 :
3834 : /*
3835 : * Extract cost numbers for topmost plan node. Note we search for a left
3836 : * paren from the end of the line to avoid being confused by other uses of
3837 : * parentheses.
3838 : */
3839 1319 : line = PQgetvalue(res, 0, 0);
3840 1319 : p = strrchr(line, '(');
3841 1319 : if (p == NULL)
3842 0 : elog(ERROR, "could not interpret EXPLAIN output: \"%s\"", line);
3843 1319 : n = sscanf(p, "(cost=%lf..%lf rows=%lf width=%d)",
3844 : startup_cost, total_cost, rows, width);
3845 1319 : if (n != 4)
3846 0 : elog(ERROR, "could not interpret EXPLAIN output: \"%s\"", line);
3847 1319 : PQclear(res);
3848 1319 : }
3849 :
3850 : /*
3851 : * Adjust the cost estimates of a foreign grouping path to include the cost of
3852 : * generating properly-sorted output.
3853 : */
3854 : static void
3855 30 : adjust_foreign_grouping_path_cost(PlannerInfo *root,
3856 : List *pathkeys,
3857 : double retrieved_rows,
3858 : double width,
3859 : double limit_tuples,
3860 : int *p_disabled_nodes,
3861 : Cost *p_startup_cost,
3862 : Cost *p_run_cost)
3863 : {
3864 : /*
3865 : * If the GROUP BY clause isn't sort-able, the plan chosen by the remote
3866 : * side is unlikely to generate properly-sorted output, so it would need
3867 : * an explicit sort; adjust the given costs with cost_sort(). Likewise,
3868 : * if the GROUP BY clause is sort-able but isn't a superset of the given
3869 : * pathkeys, adjust the costs with that function. Otherwise, adjust the
3870 : * costs by applying the same heuristic as for the scan or join case.
3871 : */
3872 30 : if (!grouping_is_sortable(root->processed_groupClause) ||
3873 30 : !pathkeys_contained_in(pathkeys, root->group_pathkeys))
3874 22 : {
3875 : Path sort_path; /* dummy for result of cost_sort */
3876 :
3877 22 : cost_sort(&sort_path,
3878 : root,
3879 : pathkeys,
3880 : 0,
3881 22 : *p_startup_cost + *p_run_cost,
3882 : retrieved_rows,
3883 : width,
3884 : 0.0,
3885 : work_mem,
3886 : limit_tuples);
3887 :
3888 22 : *p_startup_cost = sort_path.startup_cost;
3889 22 : *p_run_cost = sort_path.total_cost - sort_path.startup_cost;
3890 : }
3891 : else
3892 : {
3893 : /*
3894 : * The default extra cost seems too large for foreign-grouping cases;
3895 : * add 1/4th of that default.
3896 : */
3897 8 : double sort_multiplier = 1.0 + (DEFAULT_FDW_SORT_MULTIPLIER
3898 : - 1.0) * 0.25;
3899 :
3900 8 : *p_startup_cost *= sort_multiplier;
3901 8 : *p_run_cost *= sort_multiplier;
3902 : }
3903 30 : }
3904 :
3905 : /*
3906 : * Detect whether we want to process an EquivalenceClass member.
3907 : *
3908 : * This is a callback for use by generate_implied_equalities_for_column.
3909 : */
3910 : static bool
3911 310 : ec_member_matches_foreign(PlannerInfo *root, RelOptInfo *rel,
3912 : EquivalenceClass *ec, EquivalenceMember *em,
3913 : void *arg)
3914 : {
3915 310 : ec_member_foreign_arg *state = (ec_member_foreign_arg *) arg;
3916 310 : Expr *expr = em->em_expr;
3917 :
3918 : /*
3919 : * If we've identified what we're processing in the current scan, we only
3920 : * want to match that expression.
3921 : */
3922 310 : if (state->current != NULL)
3923 0 : return equal(expr, state->current);
3924 :
3925 : /*
3926 : * Otherwise, ignore anything we've already processed.
3927 : */
3928 310 : if (list_member(state->already_used, expr))
3929 163 : return false;
3930 :
3931 : /* This is the new target to process. */
3932 147 : state->current = expr;
3933 147 : return true;
3934 : }
3935 :
3936 : /*
3937 : * Create cursor for node's query with current parameter values.
3938 : */
3939 : static void
3940 853 : create_cursor(ForeignScanState *node)
3941 : {
3942 853 : PgFdwScanState *fsstate = (PgFdwScanState *) node->fdw_state;
3943 853 : ExprContext *econtext = node->ss.ps.ps_ExprContext;
3944 853 : int numParams = fsstate->numParams;
3945 853 : const char **values = fsstate->param_values;
3946 853 : PGconn *conn = fsstate->conn;
3947 : StringInfoData buf;
3948 : PGresult *res;
3949 :
3950 : /* First, process a pending asynchronous request, if any. */
3951 853 : if (fsstate->conn_state->pendingAreq)
3952 1 : process_pending_request(fsstate->conn_state->pendingAreq);
3953 :
3954 : /*
3955 : * Construct array of query parameter values in text format. We do the
3956 : * conversions in the short-lived per-tuple context, so as not to cause a
3957 : * memory leak over repeated scans.
3958 : */
3959 853 : if (numParams > 0)
3960 : {
3961 : MemoryContext oldcontext;
3962 :
3963 350 : oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
3964 :
3965 350 : process_query_params(econtext,
3966 : fsstate->param_flinfo,
3967 : fsstate->param_exprs,
3968 : values);
3969 :
3970 350 : MemoryContextSwitchTo(oldcontext);
3971 : }
3972 :
3973 : /* Construct the DECLARE CURSOR command */
3974 853 : initStringInfo(&buf);
3975 853 : appendStringInfo(&buf, "DECLARE c%u CURSOR FOR\n%s",
3976 : fsstate->cursor_number, fsstate->query);
3977 :
3978 : /*
3979 : * Notice that we pass NULL for paramTypes, thus forcing the remote server
3980 : * to infer types for all parameters. Since we explicitly cast every
3981 : * parameter (see deparse.c), the "inference" is trivial and will produce
3982 : * the desired result. This allows us to avoid assuming that the remote
3983 : * server has the same OIDs we do for the parameters' types.
3984 : */
3985 853 : if (!PQsendQueryParams(conn, buf.data, numParams,
3986 : NULL, values, NULL, NULL, 0))
3987 1 : pgfdw_report_error(NULL, conn, buf.data);
3988 :
3989 : /*
3990 : * Get the result, and check for success.
3991 : */
3992 852 : res = pgfdw_get_result(conn);
3993 852 : if (PQresultStatus(res) != PGRES_COMMAND_OK)
3994 3 : pgfdw_report_error(res, conn, fsstate->query);
3995 849 : PQclear(res);
3996 :
3997 : /* Mark the cursor as created, and show no tuples have been retrieved */
3998 849 : fsstate->cursor_exists = true;
3999 849 : fsstate->tuples = NULL;
4000 849 : fsstate->num_tuples = 0;
4001 849 : fsstate->next_tuple = 0;
4002 849 : fsstate->fetch_ct_2 = 0;
4003 849 : fsstate->eof_reached = false;
4004 :
4005 : /* Clean up */
4006 849 : pfree(buf.data);
4007 849 : }
4008 :
4009 : /*
4010 : * Fetch some more rows from the node's cursor.
4011 : */
4012 : static void
4013 1521 : fetch_more_data(ForeignScanState *node)
4014 : {
4015 1521 : PgFdwScanState *fsstate = (PgFdwScanState *) node->fdw_state;
4016 1521 : PGconn *conn = fsstate->conn;
4017 : PGresult *res;
4018 : int numrows;
4019 : int i;
4020 : MemoryContext oldcontext;
4021 :
4022 : /*
4023 : * We'll store the tuples in the batch_cxt. First, flush the previous
4024 : * batch.
4025 : */
4026 1521 : fsstate->tuples = NULL;
4027 1521 : MemoryContextReset(fsstate->batch_cxt);
4028 1521 : oldcontext = MemoryContextSwitchTo(fsstate->batch_cxt);
4029 :
4030 1521 : if (fsstate->async_capable)
4031 : {
4032 : Assert(fsstate->conn_state->pendingAreq);
4033 :
4034 : /*
4035 : * The query was already sent by an earlier call to
4036 : * fetch_more_data_begin. So now we just fetch the result.
4037 : */
4038 159 : res = pgfdw_get_result(conn);
4039 : /* On error, report the original query, not the FETCH. */
4040 159 : if (PQresultStatus(res) != PGRES_TUPLES_OK)
4041 0 : pgfdw_report_error(res, conn, fsstate->query);
4042 :
4043 : /* Reset per-connection state */
4044 159 : fsstate->conn_state->pendingAreq = NULL;
4045 : }
4046 : else
4047 : {
4048 : char sql[64];
4049 :
4050 : /* This is a regular synchronous fetch. */
4051 1362 : snprintf(sql, sizeof(sql), "FETCH %d FROM c%u",
4052 : fsstate->fetch_size, fsstate->cursor_number);
4053 :
4054 1362 : res = pgfdw_exec_query(conn, sql, fsstate->conn_state);
4055 : /* On error, report the original query, not the FETCH. */
4056 1361 : if (PQresultStatus(res) != PGRES_TUPLES_OK)
4057 9 : pgfdw_report_error(res, conn, fsstate->query);
4058 : }
4059 :
4060 : /* Convert the data into HeapTuples */
4061 1511 : numrows = PQntuples(res);
4062 1511 : fsstate->tuples = (HeapTuple *) palloc0(numrows * sizeof(HeapTuple));
4063 1511 : fsstate->num_tuples = numrows;
4064 1511 : fsstate->next_tuple = 0;
4065 :
4066 72857 : for (i = 0; i < numrows; i++)
4067 : {
4068 : Assert(IsA(node->ss.ps.plan, ForeignScan));
4069 :
4070 71346 : fsstate->tuples[i] =
4071 71350 : make_tuple_from_result_row(res, i,
4072 : fsstate->rel,
4073 : fsstate->attinmeta,
4074 : fsstate->retrieved_attrs,
4075 : node,
4076 : fsstate->temp_cxt);
4077 : }
4078 :
4079 : /* Update fetch_ct_2 */
4080 1507 : if (fsstate->fetch_ct_2 < 2)
4081 954 : fsstate->fetch_ct_2++;
4082 :
4083 : /* Must be EOF if we didn't get as many tuples as we asked for. */
4084 1507 : fsstate->eof_reached = (numrows < fsstate->fetch_size);
4085 :
4086 1507 : PQclear(res);
4087 :
4088 1507 : MemoryContextSwitchTo(oldcontext);
4089 1507 : }
4090 :
4091 : /*
4092 : * Force assorted GUC parameters to settings that ensure that we'll output
4093 : * data values in a form that is unambiguous to the remote server.
4094 : *
4095 : * This is rather expensive and annoying to do once per row, but there's
4096 : * little choice if we want to be sure values are transmitted accurately;
4097 : * we can't leave the settings in place between rows for fear of affecting
4098 : * user-visible computations.
4099 : *
4100 : * We use the equivalent of a function SET option to allow the settings to
4101 : * persist only until the caller calls reset_transmission_modes(). If an
4102 : * error is thrown in between, guc.c will take care of undoing the settings.
4103 : *
4104 : * The return value is the nestlevel that must be passed to
4105 : * reset_transmission_modes() to undo things.
4106 : */
4107 : int
4108 4252 : set_transmission_modes(void)
4109 : {
4110 4252 : int nestlevel = NewGUCNestLevel();
4111 :
4112 : /*
4113 : * The values set here should match what pg_dump does. See also
4114 : * configure_remote_session in connection.c.
4115 : */
4116 4252 : if (DateStyle != USE_ISO_DATES)
4117 4250 : (void) set_config_option("datestyle", "ISO",
4118 : PGC_USERSET, PGC_S_SESSION,
4119 : GUC_ACTION_SAVE, true, 0, false);
4120 4252 : if (IntervalStyle != INTSTYLE_POSTGRES)
4121 4250 : (void) set_config_option("intervalstyle", "postgres",
4122 : PGC_USERSET, PGC_S_SESSION,
4123 : GUC_ACTION_SAVE, true, 0, false);
4124 4252 : if (extra_float_digits < 3)
4125 4250 : (void) set_config_option("extra_float_digits", "3",
4126 : PGC_USERSET, PGC_S_SESSION,
4127 : GUC_ACTION_SAVE, true, 0, false);
4128 :
4129 : /*
4130 : * In addition force restrictive search_path, in case there are any
4131 : * regproc or similar constants to be printed.
4132 : */
4133 4252 : (void) set_config_option("search_path", "pg_catalog",
4134 : PGC_USERSET, PGC_S_SESSION,
4135 : GUC_ACTION_SAVE, true, 0, false);
4136 :
4137 4252 : return nestlevel;
4138 : }
4139 :
4140 : /*
4141 : * Undo the effects of set_transmission_modes().
4142 : */
4143 : void
4144 4252 : reset_transmission_modes(int nestlevel)
4145 : {
4146 4252 : AtEOXact_GUC(true, nestlevel);
4147 4252 : }
4148 :
4149 : /*
4150 : * Utility routine to close a cursor.
4151 : */
4152 : static void
4153 518 : close_cursor(PGconn *conn, unsigned int cursor_number,
4154 : PgFdwConnState *conn_state)
4155 : {
4156 : char sql[64];
4157 : PGresult *res;
4158 :
4159 518 : snprintf(sql, sizeof(sql), "CLOSE c%u", cursor_number);
4160 518 : res = pgfdw_exec_query(conn, sql, conn_state);
4161 518 : if (PQresultStatus(res) != PGRES_COMMAND_OK)
4162 1 : pgfdw_report_error(res, conn, sql);
4163 517 : PQclear(res);
4164 517 : }
4165 :
4166 : /*
4167 : * create_foreign_modify
4168 : * Construct an execution state of a foreign insert/update/delete
4169 : * operation
4170 : */
4171 : static PgFdwModifyState *
4172 182 : create_foreign_modify(EState *estate,
4173 : RangeTblEntry *rte,
4174 : ResultRelInfo *resultRelInfo,
4175 : CmdType operation,
4176 : Plan *subplan,
4177 : char *query,
4178 : List *target_attrs,
4179 : int values_end,
4180 : bool has_returning,
4181 : List *retrieved_attrs)
4182 : {
4183 : PgFdwModifyState *fmstate;
4184 182 : Relation rel = resultRelInfo->ri_RelationDesc;
4185 182 : TupleDesc tupdesc = RelationGetDescr(rel);
4186 : Oid userid;
4187 : ForeignTable *table;
4188 : UserMapping *user;
4189 : AttrNumber n_params;
4190 : Oid typefnoid;
4191 : bool isvarlena;
4192 : ListCell *lc;
4193 :
4194 : /* Begin constructing PgFdwModifyState. */
4195 182 : fmstate = palloc0_object(PgFdwModifyState);
4196 182 : fmstate->rel = rel;
4197 :
4198 : /* Identify which user to do the remote access as. */
4199 182 : userid = ExecGetResultRelCheckAsUser(resultRelInfo, estate);
4200 :
4201 : /* Get info about foreign table. */
4202 182 : table = GetForeignTable(RelationGetRelid(rel));
4203 182 : user = GetUserMapping(userid, table->serverid);
4204 :
4205 : /* Open connection; report that we'll create a prepared statement. */
4206 182 : fmstate->conn = GetConnection(user, true, &fmstate->conn_state);
4207 182 : fmstate->p_name = NULL; /* prepared statement not made yet */
4208 :
4209 : /* Set up remote query information. */
4210 182 : fmstate->query = query;
4211 182 : if (operation == CMD_INSERT)
4212 : {
4213 133 : fmstate->query = pstrdup(fmstate->query);
4214 133 : fmstate->orig_query = pstrdup(fmstate->query);
4215 : }
4216 182 : fmstate->target_attrs = target_attrs;
4217 182 : fmstate->values_end = values_end;
4218 182 : fmstate->has_returning = has_returning;
4219 182 : fmstate->retrieved_attrs = retrieved_attrs;
4220 :
4221 : /* Create context for per-tuple temp workspace. */
4222 182 : fmstate->temp_cxt = AllocSetContextCreate(estate->es_query_cxt,
4223 : "postgres_fdw temporary data",
4224 : ALLOCSET_SMALL_SIZES);
4225 :
4226 : /* Prepare for input conversion of RETURNING results. */
4227 182 : if (fmstate->has_returning)
4228 62 : fmstate->attinmeta = TupleDescGetAttInMetadata(tupdesc);
4229 :
4230 : /* Prepare for output conversion of parameters used in prepared stmt. */
4231 182 : n_params = list_length(fmstate->target_attrs) + 1;
4232 182 : fmstate->p_flinfo = palloc0_array(FmgrInfo, n_params);
4233 182 : fmstate->p_nums = 0;
4234 :
4235 182 : if (operation == CMD_UPDATE || operation == CMD_DELETE)
4236 : {
4237 : Assert(subplan != NULL);
4238 :
4239 : /* Find the ctid resjunk column in the subplan's result */
4240 49 : fmstate->ctidAttno = ExecFindJunkAttributeInTlist(subplan->targetlist,
4241 : "ctid");
4242 49 : if (!AttributeNumberIsValid(fmstate->ctidAttno))
4243 0 : elog(ERROR, "could not find junk ctid column");
4244 :
4245 : /* First transmittable parameter will be ctid */
4246 49 : getTypeOutputInfo(TIDOID, &typefnoid, &isvarlena);
4247 49 : fmgr_info(typefnoid, &fmstate->p_flinfo[fmstate->p_nums]);
4248 49 : fmstate->p_nums++;
4249 : }
4250 :
4251 182 : if (operation == CMD_INSERT || operation == CMD_UPDATE)
4252 : {
4253 : /* Set up for remaining transmittable parameters */
4254 568 : foreach(lc, fmstate->target_attrs)
4255 : {
4256 399 : int attnum = lfirst_int(lc);
4257 399 : Form_pg_attribute attr = TupleDescAttr(tupdesc, attnum - 1);
4258 :
4259 : Assert(!attr->attisdropped);
4260 :
4261 : /* Ignore generated columns; they are set to DEFAULT */
4262 399 : if (attr->attgenerated)
4263 8 : continue;
4264 391 : getTypeOutputInfo(attr->atttypid, &typefnoid, &isvarlena);
4265 391 : fmgr_info(typefnoid, &fmstate->p_flinfo[fmstate->p_nums]);
4266 391 : fmstate->p_nums++;
4267 : }
4268 : }
4269 :
4270 : Assert(fmstate->p_nums <= n_params);
4271 :
4272 : /* Set batch_size from foreign server/table options. */
4273 182 : if (operation == CMD_INSERT)
4274 133 : fmstate->batch_size = get_batch_size_option(rel);
4275 :
4276 182 : fmstate->num_slots = 1;
4277 :
4278 : /* Initialize auxiliary state */
4279 182 : fmstate->aux_fmstate = NULL;
4280 :
4281 182 : return fmstate;
4282 : }
4283 :
4284 : /*
4285 : * execute_foreign_modify
4286 : * Perform foreign-table modification as required, and fetch RETURNING
4287 : * result if any. (This is the shared guts of postgresExecForeignInsert,
4288 : * postgresExecForeignBatchInsert, postgresExecForeignUpdate, and
4289 : * postgresExecForeignDelete.)
4290 : */
4291 : static TupleTableSlot **
4292 1052 : execute_foreign_modify(EState *estate,
4293 : ResultRelInfo *resultRelInfo,
4294 : CmdType operation,
4295 : TupleTableSlot **slots,
4296 : TupleTableSlot **planSlots,
4297 : int *numSlots)
4298 : {
4299 1052 : PgFdwModifyState *fmstate = (PgFdwModifyState *) resultRelInfo->ri_FdwState;
4300 1052 : ItemPointer ctid = NULL;
4301 : const char **p_values;
4302 : PGresult *res;
4303 : int n_rows;
4304 : StringInfoData sql;
4305 :
4306 : /* The operation should be INSERT, UPDATE, or DELETE */
4307 : Assert(operation == CMD_INSERT ||
4308 : operation == CMD_UPDATE ||
4309 : operation == CMD_DELETE);
4310 :
4311 : /* First, process a pending asynchronous request, if any. */
4312 1052 : if (fmstate->conn_state->pendingAreq)
4313 1 : process_pending_request(fmstate->conn_state->pendingAreq);
4314 :
4315 : /*
4316 : * If the existing query was deparsed and prepared for a different number
4317 : * of rows, rebuild it for the proper number.
4318 : */
4319 1052 : if (operation == CMD_INSERT && fmstate->num_slots != *numSlots)
4320 : {
4321 : /* Destroy the prepared statement created previously */
4322 26 : if (fmstate->p_name)
4323 11 : deallocate_query(fmstate);
4324 :
4325 : /* Build INSERT string with numSlots records in its VALUES clause. */
4326 26 : initStringInfo(&sql);
4327 26 : rebuildInsertSql(&sql, fmstate->rel,
4328 : fmstate->orig_query, fmstate->target_attrs,
4329 : fmstate->values_end, fmstate->p_nums,
4330 26 : *numSlots - 1);
4331 26 : pfree(fmstate->query);
4332 26 : fmstate->query = sql.data;
4333 26 : fmstate->num_slots = *numSlots;
4334 : }
4335 :
4336 : /* Set up the prepared statement on the remote server, if we didn't yet */
4337 1052 : if (!fmstate->p_name)
4338 187 : prepare_foreign_modify(fmstate);
4339 :
4340 : /*
4341 : * For UPDATE/DELETE, get the ctid that was passed up as a resjunk column
4342 : */
4343 1052 : if (operation == CMD_UPDATE || operation == CMD_DELETE)
4344 : {
4345 : Datum datum;
4346 : bool isNull;
4347 :
4348 118 : datum = ExecGetJunkAttribute(planSlots[0],
4349 118 : fmstate->ctidAttno,
4350 : &isNull);
4351 : /* shouldn't ever get a null result... */
4352 118 : if (isNull)
4353 0 : elog(ERROR, "ctid is NULL");
4354 118 : ctid = (ItemPointer) DatumGetPointer(datum);
4355 : }
4356 :
4357 : /* Convert parameters needed by prepared statement to text form */
4358 1052 : p_values = convert_prep_stmt_params(fmstate, ctid, slots, *numSlots);
4359 :
4360 : /*
4361 : * Execute the prepared statement.
4362 : */
4363 1052 : if (!PQsendQueryPrepared(fmstate->conn,
4364 1052 : fmstate->p_name,
4365 1052 : fmstate->p_nums * (*numSlots),
4366 : p_values,
4367 : NULL,
4368 : NULL,
4369 : 0))
4370 0 : pgfdw_report_error(NULL, fmstate->conn, fmstate->query);
4371 :
4372 : /*
4373 : * Get the result, and check for success.
4374 : */
4375 1052 : res = pgfdw_get_result(fmstate->conn);
4376 2104 : if (PQresultStatus(res) !=
4377 1052 : (fmstate->has_returning ? PGRES_TUPLES_OK : PGRES_COMMAND_OK))
4378 5 : pgfdw_report_error(res, fmstate->conn, fmstate->query);
4379 :
4380 : /* Check number of rows affected, and fetch RETURNING tuple if any */
4381 1047 : if (fmstate->has_returning)
4382 : {
4383 : Assert(*numSlots == 1);
4384 108 : n_rows = PQntuples(res);
4385 108 : if (n_rows > 0)
4386 107 : store_returning_result(fmstate, slots[0], res);
4387 : }
4388 : else
4389 939 : n_rows = atoi(PQcmdTuples(res));
4390 :
4391 : /* And clean up */
4392 1047 : PQclear(res);
4393 :
4394 1047 : MemoryContextReset(fmstate->temp_cxt);
4395 :
4396 1047 : *numSlots = n_rows;
4397 :
4398 : /*
4399 : * Return NULL if nothing was inserted/updated/deleted on the remote end
4400 : */
4401 1047 : return (n_rows > 0) ? slots : NULL;
4402 : }
4403 :
4404 : /*
4405 : * prepare_foreign_modify
4406 : * Establish a prepared statement for execution of INSERT/UPDATE/DELETE
4407 : */
4408 : static void
4409 187 : prepare_foreign_modify(PgFdwModifyState *fmstate)
4410 : {
4411 : char prep_name[NAMEDATALEN];
4412 : char *p_name;
4413 : PGresult *res;
4414 :
4415 : /*
4416 : * The caller would already have processed a pending asynchronous request
4417 : * if any, so no need to do it here.
4418 : */
4419 :
4420 : /* Construct name we'll use for the prepared statement. */
4421 187 : snprintf(prep_name, sizeof(prep_name), "pgsql_fdw_prep_%u",
4422 : GetPrepStmtNumber(fmstate->conn));
4423 187 : p_name = pstrdup(prep_name);
4424 :
4425 : /*
4426 : * We intentionally do not specify parameter types here, but leave the
4427 : * remote server to derive them by default. This avoids possible problems
4428 : * with the remote server using different type OIDs than we do. All of
4429 : * the prepared statements we use in this module are simple enough that
4430 : * the remote server will make the right choices.
4431 : */
4432 187 : if (!PQsendPrepare(fmstate->conn,
4433 : p_name,
4434 187 : fmstate->query,
4435 : 0,
4436 : NULL))
4437 0 : pgfdw_report_error(NULL, fmstate->conn, fmstate->query);
4438 :
4439 : /*
4440 : * Get the result, and check for success.
4441 : */
4442 187 : res = pgfdw_get_result(fmstate->conn);
4443 187 : if (PQresultStatus(res) != PGRES_COMMAND_OK)
4444 0 : pgfdw_report_error(res, fmstate->conn, fmstate->query);
4445 187 : PQclear(res);
4446 :
4447 : /* This action shows that the prepare has been done. */
4448 187 : fmstate->p_name = p_name;
4449 187 : }
4450 :
4451 : /*
4452 : * convert_prep_stmt_params
4453 : * Create array of text strings representing parameter values
4454 : *
4455 : * tupleid is ctid to send, or NULL if none
4456 : * slot is slot to get remaining parameters from, or NULL if none
4457 : *
4458 : * Data is constructed in temp_cxt; caller should reset that after use.
4459 : */
4460 : static const char **
4461 1052 : convert_prep_stmt_params(PgFdwModifyState *fmstate,
4462 : ItemPointer tupleid,
4463 : TupleTableSlot **slots,
4464 : int numSlots)
4465 : {
4466 : const char **p_values;
4467 : int i;
4468 : int j;
4469 1052 : int pindex = 0;
4470 : MemoryContext oldcontext;
4471 :
4472 1052 : oldcontext = MemoryContextSwitchTo(fmstate->temp_cxt);
4473 :
4474 1052 : p_values = (const char **) palloc(sizeof(char *) * fmstate->p_nums * numSlots);
4475 :
4476 : /* ctid is provided only for UPDATE/DELETE, which don't allow batching */
4477 : Assert(!(tupleid != NULL && numSlots > 1));
4478 :
4479 : /* 1st parameter should be ctid, if it's in use */
4480 1052 : if (tupleid != NULL)
4481 : {
4482 : Assert(numSlots == 1);
4483 : /* don't need set_transmission_modes for TID output */
4484 118 : p_values[pindex] = OutputFunctionCall(&fmstate->p_flinfo[pindex],
4485 : PointerGetDatum(tupleid));
4486 118 : pindex++;
4487 : }
4488 :
4489 : /* get following parameters from slots */
4490 1052 : if (slots != NULL && fmstate->target_attrs != NIL)
4491 : {
4492 1026 : TupleDesc tupdesc = RelationGetDescr(fmstate->rel);
4493 : int nestlevel;
4494 : ListCell *lc;
4495 :
4496 1026 : nestlevel = set_transmission_modes();
4497 :
4498 2174 : for (i = 0; i < numSlots; i++)
4499 : {
4500 1148 : j = (tupleid != NULL) ? 1 : 0;
4501 4797 : foreach(lc, fmstate->target_attrs)
4502 : {
4503 3649 : int attnum = lfirst_int(lc);
4504 3649 : CompactAttribute *attr = TupleDescCompactAttr(tupdesc, attnum - 1);
4505 : Datum value;
4506 : bool isnull;
4507 :
4508 : /* Ignore generated columns; they are set to DEFAULT */
4509 3649 : if (attr->attgenerated)
4510 14 : continue;
4511 3635 : value = slot_getattr(slots[i], attnum, &isnull);
4512 3635 : if (isnull)
4513 583 : p_values[pindex] = NULL;
4514 : else
4515 3052 : p_values[pindex] = OutputFunctionCall(&fmstate->p_flinfo[j],
4516 : value);
4517 3635 : pindex++;
4518 3635 : j++;
4519 : }
4520 : }
4521 :
4522 1026 : reset_transmission_modes(nestlevel);
4523 : }
4524 :
4525 : Assert(pindex == fmstate->p_nums * numSlots);
4526 :
4527 1052 : MemoryContextSwitchTo(oldcontext);
4528 :
4529 1052 : return p_values;
4530 : }
4531 :
4532 : /*
4533 : * store_returning_result
4534 : * Store the result of a RETURNING clause
4535 : */
4536 : static void
4537 107 : store_returning_result(PgFdwModifyState *fmstate,
4538 : TupleTableSlot *slot, PGresult *res)
4539 : {
4540 : HeapTuple newtup;
4541 :
4542 107 : newtup = make_tuple_from_result_row(res, 0,
4543 : fmstate->rel,
4544 : fmstate->attinmeta,
4545 : fmstate->retrieved_attrs,
4546 : NULL,
4547 : fmstate->temp_cxt);
4548 :
4549 : /*
4550 : * The returning slot will not necessarily be suitable to store heaptuples
4551 : * directly, so allow for conversion.
4552 : */
4553 107 : ExecForceStoreHeapTuple(newtup, slot, true);
4554 107 : }
4555 :
4556 : /*
4557 : * finish_foreign_modify
4558 : * Release resources for a foreign insert/update/delete operation
4559 : */
4560 : static void
4561 160 : finish_foreign_modify(PgFdwModifyState *fmstate)
4562 : {
4563 : Assert(fmstate != NULL);
4564 :
4565 : /* If we created a prepared statement, destroy it */
4566 160 : deallocate_query(fmstate);
4567 :
4568 : /* Release remote connection */
4569 160 : ReleaseConnection(fmstate->conn);
4570 160 : fmstate->conn = NULL;
4571 160 : }
4572 :
4573 : /*
4574 : * deallocate_query
4575 : * Deallocate a prepared statement for a foreign insert/update/delete
4576 : * operation
4577 : */
4578 : static void
4579 171 : deallocate_query(PgFdwModifyState *fmstate)
4580 : {
4581 : char sql[64];
4582 : PGresult *res;
4583 :
4584 : /* do nothing if the query is not allocated */
4585 171 : if (!fmstate->p_name)
4586 4 : return;
4587 :
4588 167 : snprintf(sql, sizeof(sql), "DEALLOCATE %s", fmstate->p_name);
4589 167 : res = pgfdw_exec_query(fmstate->conn, sql, fmstate->conn_state);
4590 167 : if (PQresultStatus(res) != PGRES_COMMAND_OK)
4591 0 : pgfdw_report_error(res, fmstate->conn, sql);
4592 167 : PQclear(res);
4593 167 : pfree(fmstate->p_name);
4594 167 : fmstate->p_name = NULL;
4595 : }
4596 :
4597 : /*
4598 : * build_remote_returning
4599 : * Build a RETURNING targetlist of a remote query for performing an
4600 : * UPDATE/DELETE .. RETURNING on a join directly
4601 : */
4602 : static List *
4603 4 : build_remote_returning(Index rtindex, Relation rel, List *returningList)
4604 : {
4605 4 : bool have_wholerow = false;
4606 4 : List *tlist = NIL;
4607 : List *vars;
4608 : ListCell *lc;
4609 :
4610 : Assert(returningList);
4611 :
4612 4 : vars = pull_var_clause((Node *) returningList, PVC_INCLUDE_PLACEHOLDERS);
4613 :
4614 : /*
4615 : * If there's a whole-row reference to the target relation, then we'll
4616 : * need all the columns of the relation.
4617 : */
4618 4 : foreach(lc, vars)
4619 : {
4620 2 : Var *var = (Var *) lfirst(lc);
4621 :
4622 2 : if (IsA(var, Var) &&
4623 2 : var->varno == rtindex &&
4624 2 : var->varattno == InvalidAttrNumber)
4625 : {
4626 2 : have_wholerow = true;
4627 2 : break;
4628 : }
4629 : }
4630 :
4631 4 : if (have_wholerow)
4632 : {
4633 2 : TupleDesc tupdesc = RelationGetDescr(rel);
4634 : int i;
4635 :
4636 20 : for (i = 1; i <= tupdesc->natts; i++)
4637 : {
4638 18 : Form_pg_attribute attr = TupleDescAttr(tupdesc, i - 1);
4639 : Var *var;
4640 :
4641 : /* Ignore dropped attributes. */
4642 18 : if (attr->attisdropped)
4643 2 : continue;
4644 :
4645 16 : var = makeVar(rtindex,
4646 : i,
4647 : attr->atttypid,
4648 : attr->atttypmod,
4649 : attr->attcollation,
4650 : 0);
4651 :
4652 16 : tlist = lappend(tlist,
4653 16 : makeTargetEntry((Expr *) var,
4654 16 : list_length(tlist) + 1,
4655 : NULL,
4656 : false));
4657 : }
4658 : }
4659 :
4660 : /* Now add any remaining columns to tlist. */
4661 30 : foreach(lc, vars)
4662 : {
4663 26 : Var *var = (Var *) lfirst(lc);
4664 :
4665 : /*
4666 : * No need for whole-row references to the target relation. We don't
4667 : * need system columns other than ctid and oid either, since those are
4668 : * set locally.
4669 : */
4670 26 : if (IsA(var, Var) &&
4671 26 : var->varno == rtindex &&
4672 18 : var->varattno <= InvalidAttrNumber &&
4673 2 : var->varattno != SelfItemPointerAttributeNumber)
4674 2 : continue; /* don't need it */
4675 :
4676 24 : if (tlist_member((Expr *) var, tlist))
4677 16 : continue; /* already got it */
4678 :
4679 8 : tlist = lappend(tlist,
4680 8 : makeTargetEntry((Expr *) var,
4681 8 : list_length(tlist) + 1,
4682 : NULL,
4683 : false));
4684 : }
4685 :
4686 4 : list_free(vars);
4687 :
4688 4 : return tlist;
4689 : }
4690 :
4691 : /*
4692 : * rebuild_fdw_scan_tlist
4693 : * Build new fdw_scan_tlist of given foreign-scan plan node from given
4694 : * tlist
4695 : *
4696 : * There might be columns that the fdw_scan_tlist of the given foreign-scan
4697 : * plan node contains that the given tlist doesn't. The fdw_scan_tlist would
4698 : * have contained resjunk columns such as 'ctid' of the target relation and
4699 : * 'wholerow' of non-target relations, but the tlist might not contain them,
4700 : * for example. So, adjust the tlist so it contains all the columns specified
4701 : * in the fdw_scan_tlist; else setrefs.c will get confused.
4702 : */
4703 : static void
4704 2 : rebuild_fdw_scan_tlist(ForeignScan *fscan, List *tlist)
4705 : {
4706 2 : List *new_tlist = tlist;
4707 2 : List *old_tlist = fscan->fdw_scan_tlist;
4708 : ListCell *lc;
4709 :
4710 16 : foreach(lc, old_tlist)
4711 : {
4712 14 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
4713 :
4714 14 : if (tlist_member(tle->expr, new_tlist))
4715 8 : continue; /* already got it */
4716 :
4717 6 : new_tlist = lappend(new_tlist,
4718 6 : makeTargetEntry(tle->expr,
4719 6 : list_length(new_tlist) + 1,
4720 : NULL,
4721 : false));
4722 : }
4723 2 : fscan->fdw_scan_tlist = new_tlist;
4724 2 : }
4725 :
4726 : /*
4727 : * Execute a direct UPDATE/DELETE statement.
4728 : */
4729 : static void
4730 71 : execute_dml_stmt(ForeignScanState *node)
4731 : {
4732 71 : PgFdwDirectModifyState *dmstate = (PgFdwDirectModifyState *) node->fdw_state;
4733 71 : ExprContext *econtext = node->ss.ps.ps_ExprContext;
4734 71 : int numParams = dmstate->numParams;
4735 71 : const char **values = dmstate->param_values;
4736 :
4737 : /* First, process a pending asynchronous request, if any. */
4738 71 : if (dmstate->conn_state->pendingAreq)
4739 1 : process_pending_request(dmstate->conn_state->pendingAreq);
4740 :
4741 : /*
4742 : * Construct array of query parameter values in text format.
4743 : */
4744 71 : if (numParams > 0)
4745 0 : process_query_params(econtext,
4746 : dmstate->param_flinfo,
4747 : dmstate->param_exprs,
4748 : values);
4749 :
4750 : /*
4751 : * Notice that we pass NULL for paramTypes, thus forcing the remote server
4752 : * to infer types for all parameters. Since we explicitly cast every
4753 : * parameter (see deparse.c), the "inference" is trivial and will produce
4754 : * the desired result. This allows us to avoid assuming that the remote
4755 : * server has the same OIDs we do for the parameters' types.
4756 : */
4757 71 : if (!PQsendQueryParams(dmstate->conn, dmstate->query, numParams,
4758 : NULL, values, NULL, NULL, 0))
4759 0 : pgfdw_report_error(NULL, dmstate->conn, dmstate->query);
4760 :
4761 : /*
4762 : * Get the result, and check for success.
4763 : */
4764 71 : dmstate->result = pgfdw_get_result(dmstate->conn);
4765 142 : if (PQresultStatus(dmstate->result) !=
4766 71 : (dmstate->has_returning ? PGRES_TUPLES_OK : PGRES_COMMAND_OK))
4767 4 : pgfdw_report_error(dmstate->result, dmstate->conn,
4768 4 : dmstate->query);
4769 :
4770 : /*
4771 : * The result potentially needs to survive across multiple executor row
4772 : * cycles, so move it to the context where the dmstate is.
4773 : */
4774 67 : dmstate->result = libpqsrv_PGresultSetParent(dmstate->result,
4775 : GetMemoryChunkContext(dmstate));
4776 :
4777 : /* Get the number of rows affected. */
4778 67 : if (dmstate->has_returning)
4779 14 : dmstate->num_tuples = PQntuples(dmstate->result);
4780 : else
4781 53 : dmstate->num_tuples = atoi(PQcmdTuples(dmstate->result));
4782 67 : }
4783 :
4784 : /*
4785 : * Get the result of a RETURNING clause.
4786 : */
4787 : static TupleTableSlot *
4788 364 : get_returning_data(ForeignScanState *node)
4789 : {
4790 364 : PgFdwDirectModifyState *dmstate = (PgFdwDirectModifyState *) node->fdw_state;
4791 364 : EState *estate = node->ss.ps.state;
4792 364 : ResultRelInfo *resultRelInfo = node->resultRelInfo;
4793 364 : TupleTableSlot *slot = node->ss.ss_ScanTupleSlot;
4794 : TupleTableSlot *resultSlot;
4795 :
4796 : Assert(resultRelInfo->ri_projectReturning);
4797 :
4798 : /* If we didn't get any tuples, must be end of data. */
4799 364 : if (dmstate->next_tuple >= dmstate->num_tuples)
4800 17 : return ExecClearTuple(slot);
4801 :
4802 : /* Increment the command es_processed count if necessary. */
4803 347 : if (dmstate->set_processed)
4804 346 : estate->es_processed += 1;
4805 :
4806 : /*
4807 : * Store a RETURNING tuple. If has_returning is false, just emit a dummy
4808 : * tuple. (has_returning is false when the local query is of the form
4809 : * "UPDATE/DELETE .. RETURNING 1" for example.)
4810 : */
4811 347 : if (!dmstate->has_returning)
4812 : {
4813 12 : ExecStoreAllNullTuple(slot);
4814 12 : resultSlot = slot;
4815 : }
4816 : else
4817 : {
4818 : HeapTuple newtup;
4819 :
4820 335 : newtup = make_tuple_from_result_row(dmstate->result,
4821 : dmstate->next_tuple,
4822 : dmstate->rel,
4823 : dmstate->attinmeta,
4824 : dmstate->retrieved_attrs,
4825 : node,
4826 : dmstate->temp_cxt);
4827 335 : ExecStoreHeapTuple(newtup, slot, false);
4828 : /* Get the updated/deleted tuple. */
4829 335 : if (dmstate->rel)
4830 319 : resultSlot = slot;
4831 : else
4832 16 : resultSlot = apply_returning_filter(dmstate, resultRelInfo, slot, estate);
4833 : }
4834 347 : dmstate->next_tuple++;
4835 :
4836 : /* Make slot available for evaluation of the local query RETURNING list. */
4837 347 : resultRelInfo->ri_projectReturning->pi_exprContext->ecxt_scantuple =
4838 : resultSlot;
4839 :
4840 347 : return slot;
4841 : }
4842 :
4843 : /*
4844 : * Initialize a filter to extract an updated/deleted tuple from a scan tuple.
4845 : */
4846 : static void
4847 1 : init_returning_filter(PgFdwDirectModifyState *dmstate,
4848 : List *fdw_scan_tlist,
4849 : Index rtindex)
4850 : {
4851 1 : TupleDesc resultTupType = RelationGetDescr(dmstate->resultRel);
4852 : ListCell *lc;
4853 : int i;
4854 :
4855 : /*
4856 : * Calculate the mapping between the fdw_scan_tlist's entries and the
4857 : * result tuple's attributes.
4858 : *
4859 : * The "map" is an array of indexes of the result tuple's attributes in
4860 : * fdw_scan_tlist, i.e., one entry for every attribute of the result
4861 : * tuple. We store zero for any attributes that don't have the
4862 : * corresponding entries in that list, marking that a NULL is needed in
4863 : * the result tuple.
4864 : *
4865 : * Also get the indexes of the entries for ctid and oid if any.
4866 : */
4867 1 : dmstate->attnoMap = (AttrNumber *)
4868 1 : palloc0(resultTupType->natts * sizeof(AttrNumber));
4869 :
4870 1 : dmstate->ctidAttno = dmstate->oidAttno = 0;
4871 :
4872 1 : i = 1;
4873 1 : dmstate->hasSystemCols = false;
4874 16 : foreach(lc, fdw_scan_tlist)
4875 : {
4876 15 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
4877 15 : Var *var = (Var *) tle->expr;
4878 :
4879 : Assert(IsA(var, Var));
4880 :
4881 : /*
4882 : * If the Var is a column of the target relation to be retrieved from
4883 : * the foreign server, get the index of the entry.
4884 : */
4885 25 : if (var->varno == rtindex &&
4886 10 : list_member_int(dmstate->retrieved_attrs, i))
4887 : {
4888 8 : int attrno = var->varattno;
4889 :
4890 8 : if (attrno < 0)
4891 : {
4892 : /*
4893 : * We don't retrieve system columns other than ctid and oid.
4894 : */
4895 0 : if (attrno == SelfItemPointerAttributeNumber)
4896 0 : dmstate->ctidAttno = i;
4897 : else
4898 : Assert(false);
4899 0 : dmstate->hasSystemCols = true;
4900 : }
4901 : else
4902 : {
4903 : /*
4904 : * We don't retrieve whole-row references to the target
4905 : * relation either.
4906 : */
4907 : Assert(attrno > 0);
4908 :
4909 8 : dmstate->attnoMap[attrno - 1] = i;
4910 : }
4911 : }
4912 15 : i++;
4913 : }
4914 1 : }
4915 :
4916 : /*
4917 : * Extract and return an updated/deleted tuple from a scan tuple.
4918 : */
4919 : static TupleTableSlot *
4920 16 : apply_returning_filter(PgFdwDirectModifyState *dmstate,
4921 : ResultRelInfo *resultRelInfo,
4922 : TupleTableSlot *slot,
4923 : EState *estate)
4924 : {
4925 16 : TupleDesc resultTupType = RelationGetDescr(dmstate->resultRel);
4926 : TupleTableSlot *resultSlot;
4927 : Datum *values;
4928 : bool *isnull;
4929 : Datum *old_values;
4930 : bool *old_isnull;
4931 : int i;
4932 :
4933 : /*
4934 : * Use the return tuple slot as a place to store the result tuple.
4935 : */
4936 16 : resultSlot = ExecGetReturningSlot(estate, resultRelInfo);
4937 :
4938 : /*
4939 : * Extract all the values of the scan tuple.
4940 : */
4941 16 : slot_getallattrs(slot);
4942 16 : old_values = slot->tts_values;
4943 16 : old_isnull = slot->tts_isnull;
4944 :
4945 : /*
4946 : * Prepare to build the result tuple.
4947 : */
4948 16 : ExecClearTuple(resultSlot);
4949 16 : values = resultSlot->tts_values;
4950 16 : isnull = resultSlot->tts_isnull;
4951 :
4952 : /*
4953 : * Transpose data into proper fields of the result tuple.
4954 : */
4955 160 : for (i = 0; i < resultTupType->natts; i++)
4956 : {
4957 144 : int j = dmstate->attnoMap[i];
4958 :
4959 144 : if (j == 0)
4960 : {
4961 16 : values[i] = (Datum) 0;
4962 16 : isnull[i] = true;
4963 : }
4964 : else
4965 : {
4966 128 : values[i] = old_values[j - 1];
4967 128 : isnull[i] = old_isnull[j - 1];
4968 : }
4969 : }
4970 :
4971 : /*
4972 : * Build the virtual tuple.
4973 : */
4974 16 : ExecStoreVirtualTuple(resultSlot);
4975 :
4976 : /*
4977 : * If we have any system columns to return, materialize a heap tuple in
4978 : * the slot from column values set above and install system columns in
4979 : * that tuple.
4980 : */
4981 16 : if (dmstate->hasSystemCols)
4982 : {
4983 0 : HeapTuple resultTup = ExecFetchSlotHeapTuple(resultSlot, true, NULL);
4984 :
4985 : /* ctid */
4986 0 : if (dmstate->ctidAttno)
4987 : {
4988 0 : ItemPointer ctid = NULL;
4989 :
4990 0 : ctid = (ItemPointer) DatumGetPointer(old_values[dmstate->ctidAttno - 1]);
4991 0 : resultTup->t_self = *ctid;
4992 : }
4993 :
4994 : /*
4995 : * And remaining columns
4996 : *
4997 : * Note: since we currently don't allow the target relation to appear
4998 : * on the nullable side of an outer join, any system columns wouldn't
4999 : * go to NULL.
5000 : *
5001 : * Note: no need to care about tableoid here because it will be
5002 : * initialized in ExecProcessReturning().
5003 : */
5004 0 : HeapTupleHeaderSetXmin(resultTup->t_data, InvalidTransactionId);
5005 0 : HeapTupleHeaderSetXmax(resultTup->t_data, InvalidTransactionId);
5006 0 : HeapTupleHeaderSetCmin(resultTup->t_data, InvalidTransactionId);
5007 : }
5008 :
5009 : /*
5010 : * And return the result tuple.
5011 : */
5012 16 : return resultSlot;
5013 : }
5014 :
5015 : /*
5016 : * Prepare for processing of parameters used in remote query.
5017 : */
5018 : static void
5019 23 : prepare_query_params(PlanState *node,
5020 : List *fdw_exprs,
5021 : int numParams,
5022 : FmgrInfo **param_flinfo,
5023 : List **param_exprs,
5024 : const char ***param_values)
5025 : {
5026 : int i;
5027 : ListCell *lc;
5028 :
5029 : Assert(numParams > 0);
5030 :
5031 : /* Prepare for output conversion of parameters used in remote query. */
5032 23 : *param_flinfo = palloc0_array(FmgrInfo, numParams);
5033 :
5034 23 : i = 0;
5035 47 : foreach(lc, fdw_exprs)
5036 : {
5037 24 : Node *param_expr = (Node *) lfirst(lc);
5038 : Oid typefnoid;
5039 : bool isvarlena;
5040 :
5041 24 : getTypeOutputInfo(exprType(param_expr), &typefnoid, &isvarlena);
5042 24 : fmgr_info(typefnoid, &(*param_flinfo)[i]);
5043 24 : i++;
5044 : }
5045 :
5046 : /*
5047 : * Prepare remote-parameter expressions for evaluation. (Note: in
5048 : * practice, we expect that all these expressions will be just Params, so
5049 : * we could possibly do something more efficient than using the full
5050 : * expression-eval machinery for this. But probably there would be little
5051 : * benefit, and it'd require postgres_fdw to know more than is desirable
5052 : * about Param evaluation.)
5053 : */
5054 23 : *param_exprs = ExecInitExprList(fdw_exprs, node);
5055 :
5056 : /* Allocate buffer for text form of query parameters. */
5057 23 : *param_values = (const char **) palloc0(numParams * sizeof(char *));
5058 23 : }
5059 :
5060 : /*
5061 : * Construct array of query parameter values in text format.
5062 : */
5063 : static void
5064 350 : process_query_params(ExprContext *econtext,
5065 : FmgrInfo *param_flinfo,
5066 : List *param_exprs,
5067 : const char **param_values)
5068 : {
5069 : int nestlevel;
5070 : int i;
5071 : ListCell *lc;
5072 :
5073 350 : nestlevel = set_transmission_modes();
5074 :
5075 350 : i = 0;
5076 900 : foreach(lc, param_exprs)
5077 : {
5078 550 : ExprState *expr_state = (ExprState *) lfirst(lc);
5079 : Datum expr_value;
5080 : bool isNull;
5081 :
5082 : /* Evaluate the parameter expression */
5083 550 : expr_value = ExecEvalExpr(expr_state, econtext, &isNull);
5084 :
5085 : /*
5086 : * Get string representation of each parameter value by invoking
5087 : * type-specific output function, unless the value is null.
5088 : */
5089 550 : if (isNull)
5090 0 : param_values[i] = NULL;
5091 : else
5092 550 : param_values[i] = OutputFunctionCall(¶m_flinfo[i], expr_value);
5093 :
5094 550 : i++;
5095 : }
5096 :
5097 350 : reset_transmission_modes(nestlevel);
5098 350 : }
5099 :
5100 : /*
5101 : * postgresAnalyzeForeignTable
5102 : * Test whether analyzing this foreign table is supported
5103 : */
5104 : static bool
5105 52 : postgresAnalyzeForeignTable(Relation relation,
5106 : AcquireSampleRowsFunc *func,
5107 : BlockNumber *totalpages)
5108 : {
5109 : ForeignTable *table;
5110 : UserMapping *user;
5111 : PGconn *conn;
5112 : StringInfoData sql;
5113 : PGresult *res;
5114 :
5115 : /* Return the row-analysis function pointer */
5116 52 : *func = postgresAcquireSampleRowsFunc;
5117 :
5118 : /*
5119 : * Now we have to get the number of pages. It's annoying that the ANALYZE
5120 : * API requires us to return that now, because it forces some duplication
5121 : * of effort between this routine and postgresAcquireSampleRowsFunc. But
5122 : * it's probably not worth redefining that API at this point.
5123 : */
5124 :
5125 : /*
5126 : * Get the connection to use. We do the remote access as the table's
5127 : * owner, even if the ANALYZE was started by some other user.
5128 : */
5129 52 : table = GetForeignTable(RelationGetRelid(relation));
5130 52 : user = GetUserMapping(relation->rd_rel->relowner, table->serverid);
5131 52 : conn = GetConnection(user, false, NULL);
5132 :
5133 : /*
5134 : * Construct command to get page count for relation.
5135 : */
5136 52 : initStringInfo(&sql);
5137 52 : deparseAnalyzeSizeSql(&sql, relation);
5138 :
5139 52 : res = pgfdw_exec_query(conn, sql.data, NULL);
5140 52 : if (PQresultStatus(res) != PGRES_TUPLES_OK)
5141 0 : pgfdw_report_error(res, conn, sql.data);
5142 :
5143 52 : if (PQntuples(res) != 1 || PQnfields(res) != 1)
5144 0 : elog(ERROR, "unexpected result from deparseAnalyzeSizeSql query");
5145 52 : *totalpages = strtoul(PQgetvalue(res, 0, 0), NULL, 10);
5146 52 : PQclear(res);
5147 :
5148 52 : ReleaseConnection(conn);
5149 :
5150 52 : return true;
5151 : }
5152 :
5153 : /*
5154 : * postgresGetAnalyzeInfoForForeignTable
5155 : * Count tuples in foreign table (just get pg_class.reltuples).
5156 : *
5157 : * can_tablesample determines if the remote relation supports acquiring the
5158 : * sample using TABLESAMPLE.
5159 : */
5160 : static double
5161 46 : postgresGetAnalyzeInfoForForeignTable(Relation relation, bool *can_tablesample)
5162 : {
5163 : ForeignTable *table;
5164 : UserMapping *user;
5165 : PGconn *conn;
5166 : StringInfoData sql;
5167 : PGresult *res;
5168 : double reltuples;
5169 : char relkind;
5170 :
5171 : /* assume the remote relation does not support TABLESAMPLE */
5172 46 : *can_tablesample = false;
5173 :
5174 : /*
5175 : * Get the connection to use. We do the remote access as the table's
5176 : * owner, even if the ANALYZE was started by some other user.
5177 : */
5178 46 : table = GetForeignTable(RelationGetRelid(relation));
5179 46 : user = GetUserMapping(relation->rd_rel->relowner, table->serverid);
5180 46 : conn = GetConnection(user, false, NULL);
5181 :
5182 : /*
5183 : * Construct command to get page count for relation.
5184 : */
5185 46 : initStringInfo(&sql);
5186 46 : deparseAnalyzeInfoSql(&sql, relation);
5187 :
5188 46 : res = pgfdw_exec_query(conn, sql.data, NULL);
5189 46 : if (PQresultStatus(res) != PGRES_TUPLES_OK)
5190 0 : pgfdw_report_error(res, conn, sql.data);
5191 :
5192 46 : if (PQntuples(res) != 1 || PQnfields(res) != RELSTATS_NUM_FIELDS)
5193 0 : elog(ERROR, "unexpected result from deparseAnalyzeInfoSql query");
5194 : /* We don't use relpages here */
5195 46 : reltuples = strtod(PQgetvalue(res, 0, RELSTATS_RELTUPLES), NULL);
5196 46 : relkind = *(PQgetvalue(res, 0, RELSTATS_RELKIND));
5197 46 : PQclear(res);
5198 :
5199 46 : ReleaseConnection(conn);
5200 :
5201 : /* TABLESAMPLE is supported only for regular tables and matviews */
5202 0 : *can_tablesample = (relkind == RELKIND_RELATION ||
5203 46 : relkind == RELKIND_MATVIEW ||
5204 46 : relkind == RELKIND_PARTITIONED_TABLE);
5205 :
5206 46 : return reltuples;
5207 : }
5208 :
5209 : /*
5210 : * Acquire a random sample of rows from foreign table managed by postgres_fdw.
5211 : *
5212 : * Selected rows are returned in the caller-allocated array rows[],
5213 : * which must have at least targrows entries.
5214 : * The actual number of rows selected is returned as the function result.
5215 : * We also count the total number of rows in the table and return it into
5216 : * *totalrows. Note that *totaldeadrows is always set to 0.
5217 : *
5218 : * Note that the returned list of rows is not always in order by physical
5219 : * position in the table. Therefore, correlation estimates derived later
5220 : * may be meaningless, but it's OK because we don't use the estimates
5221 : * currently (the planner only pays attention to correlation for indexscans).
5222 : */
5223 : static int
5224 52 : postgresAcquireSampleRowsFunc(Relation relation, int elevel,
5225 : HeapTuple *rows, int targrows,
5226 : double *totalrows,
5227 : double *totaldeadrows)
5228 : {
5229 : PgFdwAnalyzeState astate;
5230 : ForeignTable *table;
5231 : ForeignServer *server;
5232 : UserMapping *user;
5233 : PGconn *conn;
5234 : int server_version_num;
5235 52 : PgFdwSamplingMethod method = ANALYZE_SAMPLE_AUTO; /* auto is default */
5236 52 : double sample_frac = -1.0;
5237 52 : double reltuples = -1.0;
5238 : unsigned int cursor_number;
5239 : StringInfoData sql;
5240 : PGresult *res;
5241 : char fetch_sql[64];
5242 : int fetch_size;
5243 : ListCell *lc;
5244 :
5245 : /* Initialize workspace state */
5246 52 : astate.rel = relation;
5247 52 : astate.attinmeta = TupleDescGetAttInMetadata(RelationGetDescr(relation));
5248 :
5249 52 : astate.rows = rows;
5250 52 : astate.targrows = targrows;
5251 52 : astate.numrows = 0;
5252 52 : astate.samplerows = 0;
5253 52 : astate.rowstoskip = -1; /* -1 means not set yet */
5254 52 : reservoir_init_selection_state(&astate.rstate, targrows);
5255 :
5256 : /* Remember ANALYZE context, and create a per-tuple temp context */
5257 52 : astate.anl_cxt = CurrentMemoryContext;
5258 52 : astate.temp_cxt = AllocSetContextCreate(CurrentMemoryContext,
5259 : "postgres_fdw temporary data",
5260 : ALLOCSET_SMALL_SIZES);
5261 :
5262 : /*
5263 : * Get the connection to use. We do the remote access as the table's
5264 : * owner, even if the ANALYZE was started by some other user.
5265 : */
5266 52 : table = GetForeignTable(RelationGetRelid(relation));
5267 52 : server = GetForeignServer(table->serverid);
5268 52 : user = GetUserMapping(relation->rd_rel->relowner, table->serverid);
5269 52 : conn = GetConnection(user, false, NULL);
5270 :
5271 : /* We'll need server version, so fetch it now. */
5272 52 : server_version_num = PQserverVersion(conn);
5273 :
5274 : /*
5275 : * What sampling method should we use?
5276 : */
5277 244 : foreach(lc, server->options)
5278 : {
5279 202 : DefElem *def = (DefElem *) lfirst(lc);
5280 :
5281 202 : if (strcmp(def->defname, "analyze_sampling") == 0)
5282 : {
5283 10 : char *value = defGetString(def);
5284 :
5285 10 : if (strcmp(value, "off") == 0)
5286 6 : method = ANALYZE_SAMPLE_OFF;
5287 4 : else if (strcmp(value, "auto") == 0)
5288 1 : method = ANALYZE_SAMPLE_AUTO;
5289 3 : else if (strcmp(value, "random") == 0)
5290 1 : method = ANALYZE_SAMPLE_RANDOM;
5291 2 : else if (strcmp(value, "system") == 0)
5292 1 : method = ANALYZE_SAMPLE_SYSTEM;
5293 1 : else if (strcmp(value, "bernoulli") == 0)
5294 1 : method = ANALYZE_SAMPLE_BERNOULLI;
5295 :
5296 10 : break;
5297 : }
5298 : }
5299 :
5300 123 : foreach(lc, table->options)
5301 : {
5302 71 : DefElem *def = (DefElem *) lfirst(lc);
5303 :
5304 71 : if (strcmp(def->defname, "analyze_sampling") == 0)
5305 : {
5306 0 : char *value = defGetString(def);
5307 :
5308 0 : if (strcmp(value, "off") == 0)
5309 0 : method = ANALYZE_SAMPLE_OFF;
5310 0 : else if (strcmp(value, "auto") == 0)
5311 0 : method = ANALYZE_SAMPLE_AUTO;
5312 0 : else if (strcmp(value, "random") == 0)
5313 0 : method = ANALYZE_SAMPLE_RANDOM;
5314 0 : else if (strcmp(value, "system") == 0)
5315 0 : method = ANALYZE_SAMPLE_SYSTEM;
5316 0 : else if (strcmp(value, "bernoulli") == 0)
5317 0 : method = ANALYZE_SAMPLE_BERNOULLI;
5318 :
5319 0 : break;
5320 : }
5321 : }
5322 :
5323 : /*
5324 : * Error-out if explicitly required one of the TABLESAMPLE methods, but
5325 : * the server does not support it.
5326 : */
5327 52 : if ((server_version_num < 95000) &&
5328 0 : (method == ANALYZE_SAMPLE_SYSTEM ||
5329 : method == ANALYZE_SAMPLE_BERNOULLI))
5330 0 : ereport(ERROR,
5331 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
5332 : errmsg("remote server does not support TABLESAMPLE feature")));
5333 :
5334 : /*
5335 : * If we've decided to do remote sampling, calculate the sampling rate. We
5336 : * need to get the number of tuples from the remote server, but skip that
5337 : * network round-trip if not needed.
5338 : */
5339 52 : if (method != ANALYZE_SAMPLE_OFF)
5340 : {
5341 : bool can_tablesample;
5342 :
5343 46 : reltuples = postgresGetAnalyzeInfoForForeignTable(relation,
5344 : &can_tablesample);
5345 :
5346 : /*
5347 : * Make sure we're not choosing TABLESAMPLE when the remote relation
5348 : * does not support that. But only do this for "auto" - if the user
5349 : * explicitly requested BERNOULLI/SYSTEM, it's better to fail.
5350 : */
5351 46 : if (!can_tablesample && (method == ANALYZE_SAMPLE_AUTO))
5352 0 : method = ANALYZE_SAMPLE_RANDOM;
5353 :
5354 : /*
5355 : * Remote's reltuples could be 0 or -1 if the table has never been
5356 : * vacuumed/analyzed. In that case, disable sampling after all.
5357 : */
5358 46 : if ((reltuples <= 0) || (targrows >= reltuples))
5359 46 : method = ANALYZE_SAMPLE_OFF;
5360 : else
5361 : {
5362 : /*
5363 : * All supported sampling methods require sampling rate, not
5364 : * target rows directly, so we calculate that using the remote
5365 : * reltuples value. That's imperfect, because it might be off a
5366 : * good deal, but that's not something we can (or should) address
5367 : * here.
5368 : *
5369 : * If reltuples is too low (i.e. when table grew), we'll end up
5370 : * sampling more rows - but then we'll apply the local sampling,
5371 : * so we get the expected sample size. This is the same outcome as
5372 : * without remote sampling.
5373 : *
5374 : * If reltuples is too high (e.g. after bulk DELETE), we will end
5375 : * up sampling too few rows.
5376 : *
5377 : * We can't really do much better here - we could try sampling a
5378 : * bit more rows, but we don't know how off the reltuples value is
5379 : * so how much is "a bit more"?
5380 : *
5381 : * Furthermore, the targrows value for partitions is determined
5382 : * based on table size (relpages), which can be off in different
5383 : * ways too. Adjusting the sampling rate here might make the issue
5384 : * worse.
5385 : */
5386 0 : sample_frac = targrows / reltuples;
5387 :
5388 : /*
5389 : * We should never get sampling rate outside the valid range
5390 : * (between 0.0 and 1.0), because those cases should be covered by
5391 : * the previous branch that sets ANALYZE_SAMPLE_OFF.
5392 : */
5393 : Assert(sample_frac >= 0.0 && sample_frac <= 1.0);
5394 : }
5395 : }
5396 :
5397 : /*
5398 : * For "auto" method, pick the one we believe is best. For servers with
5399 : * TABLESAMPLE support we pick BERNOULLI, for old servers we fall-back to
5400 : * random() to at least reduce network transfer.
5401 : */
5402 52 : if (method == ANALYZE_SAMPLE_AUTO)
5403 : {
5404 0 : if (server_version_num < 95000)
5405 0 : method = ANALYZE_SAMPLE_RANDOM;
5406 : else
5407 0 : method = ANALYZE_SAMPLE_BERNOULLI;
5408 : }
5409 :
5410 : /*
5411 : * Construct cursor that retrieves whole rows from remote.
5412 : */
5413 52 : cursor_number = GetCursorNumber(conn);
5414 52 : initStringInfo(&sql);
5415 52 : appendStringInfo(&sql, "DECLARE c%u CURSOR FOR ", cursor_number);
5416 :
5417 52 : deparseAnalyzeSql(&sql, relation, method, sample_frac, &astate.retrieved_attrs);
5418 :
5419 52 : res = pgfdw_exec_query(conn, sql.data, NULL);
5420 52 : if (PQresultStatus(res) != PGRES_COMMAND_OK)
5421 0 : pgfdw_report_error(res, conn, sql.data);
5422 52 : PQclear(res);
5423 :
5424 : /*
5425 : * Determine the fetch size. The default is arbitrary, but shouldn't be
5426 : * enormous.
5427 : */
5428 52 : fetch_size = 100;
5429 254 : foreach(lc, server->options)
5430 : {
5431 202 : DefElem *def = (DefElem *) lfirst(lc);
5432 :
5433 202 : if (strcmp(def->defname, "fetch_size") == 0)
5434 : {
5435 0 : (void) parse_int(defGetString(def), &fetch_size, 0, NULL);
5436 0 : break;
5437 : }
5438 : }
5439 123 : foreach(lc, table->options)
5440 : {
5441 71 : DefElem *def = (DefElem *) lfirst(lc);
5442 :
5443 71 : if (strcmp(def->defname, "fetch_size") == 0)
5444 : {
5445 0 : (void) parse_int(defGetString(def), &fetch_size, 0, NULL);
5446 0 : break;
5447 : }
5448 : }
5449 :
5450 : /* Construct command to fetch rows from remote. */
5451 52 : snprintf(fetch_sql, sizeof(fetch_sql), "FETCH %d FROM c%u",
5452 : fetch_size, cursor_number);
5453 :
5454 : /* Retrieve and process rows a batch at a time. */
5455 : for (;;)
5456 222 : {
5457 : int numrows;
5458 : int i;
5459 :
5460 : /* Allow users to cancel long query */
5461 274 : CHECK_FOR_INTERRUPTS();
5462 :
5463 : /*
5464 : * XXX possible future improvement: if rowstoskip is large, we could
5465 : * issue a MOVE rather than physically fetching the rows, then just
5466 : * adjust rowstoskip and samplerows appropriately.
5467 : */
5468 :
5469 : /* Fetch some rows */
5470 274 : res = pgfdw_exec_query(conn, fetch_sql, NULL);
5471 : /* On error, report the original query, not the FETCH. */
5472 274 : if (PQresultStatus(res) != PGRES_TUPLES_OK)
5473 0 : pgfdw_report_error(res, conn, sql.data);
5474 :
5475 : /* Process whatever we got. */
5476 274 : numrows = PQntuples(res);
5477 23017 : for (i = 0; i < numrows; i++)
5478 22744 : analyze_row_processor(res, i, &astate);
5479 :
5480 273 : PQclear(res);
5481 :
5482 : /* Must be EOF if we didn't get all the rows requested. */
5483 273 : if (numrows < fetch_size)
5484 51 : break;
5485 : }
5486 :
5487 : /* Close the cursor, just to be tidy. */
5488 51 : close_cursor(conn, cursor_number, NULL);
5489 :
5490 51 : ReleaseConnection(conn);
5491 :
5492 : /* We assume that we have no dead tuple. */
5493 51 : *totaldeadrows = 0.0;
5494 :
5495 : /*
5496 : * Without sampling, we've retrieved all living tuples from foreign
5497 : * server, so report that as totalrows. Otherwise use the reltuples
5498 : * estimate we got from the remote side.
5499 : */
5500 51 : if (method == ANALYZE_SAMPLE_OFF)
5501 51 : *totalrows = astate.samplerows;
5502 : else
5503 0 : *totalrows = reltuples;
5504 :
5505 : /*
5506 : * Emit some interesting relation info
5507 : */
5508 51 : ereport(elevel,
5509 : (errmsg("\"%s\": table contains %.0f rows, %d rows in sample",
5510 : RelationGetRelationName(relation),
5511 : *totalrows, astate.numrows)));
5512 :
5513 51 : return astate.numrows;
5514 : }
5515 :
5516 : /*
5517 : * Collect sample rows from the result of query.
5518 : * - Use all tuples in sample until target # of samples are collected.
5519 : * - Subsequently, replace already-sampled tuples randomly.
5520 : */
5521 : static void
5522 22744 : analyze_row_processor(PGresult *res, int row, PgFdwAnalyzeState *astate)
5523 : {
5524 22744 : int targrows = astate->targrows;
5525 : int pos; /* array index to store tuple in */
5526 : MemoryContext oldcontext;
5527 :
5528 : /* Always increment sample row counter. */
5529 22744 : astate->samplerows += 1;
5530 :
5531 : /*
5532 : * Determine the slot where this sample row should be stored. Set pos to
5533 : * negative value to indicate the row should be skipped.
5534 : */
5535 22744 : if (astate->numrows < targrows)
5536 : {
5537 : /* First targrows rows are always included into the sample */
5538 22744 : pos = astate->numrows++;
5539 : }
5540 : else
5541 : {
5542 : /*
5543 : * Now we start replacing tuples in the sample until we reach the end
5544 : * of the relation. Same algorithm as in acquire_sample_rows in
5545 : * analyze.c; see Jeff Vitter's paper.
5546 : */
5547 0 : if (astate->rowstoskip < 0)
5548 0 : astate->rowstoskip = reservoir_get_next_S(&astate->rstate, astate->samplerows, targrows);
5549 :
5550 0 : if (astate->rowstoskip <= 0)
5551 : {
5552 : /* Choose a random reservoir element to replace. */
5553 0 : pos = (int) (targrows * sampler_random_fract(&astate->rstate.randstate));
5554 : Assert(pos >= 0 && pos < targrows);
5555 0 : heap_freetuple(astate->rows[pos]);
5556 : }
5557 : else
5558 : {
5559 : /* Skip this tuple. */
5560 0 : pos = -1;
5561 : }
5562 :
5563 0 : astate->rowstoskip -= 1;
5564 : }
5565 :
5566 22744 : if (pos >= 0)
5567 : {
5568 : /*
5569 : * Create sample tuple from current result row, and store it in the
5570 : * position determined above. The tuple has to be created in anl_cxt.
5571 : */
5572 22744 : oldcontext = MemoryContextSwitchTo(astate->anl_cxt);
5573 :
5574 22744 : astate->rows[pos] = make_tuple_from_result_row(res, row,
5575 : astate->rel,
5576 : astate->attinmeta,
5577 : astate->retrieved_attrs,
5578 : NULL,
5579 : astate->temp_cxt);
5580 :
5581 22743 : MemoryContextSwitchTo(oldcontext);
5582 : }
5583 22743 : }
5584 :
5585 : /*
5586 : * postgresImportForeignStatistics
5587 : * Attempt to fetch/restore remote statistics instead of sampling.
5588 : */
5589 : static bool
5590 43 : postgresImportForeignStatistics(Relation relation, List *va_cols, int elevel)
5591 : {
5592 43 : const char *schemaname = NULL;
5593 43 : const char *relname = NULL;
5594 : ForeignTable *table;
5595 : ForeignServer *server;
5596 43 : RemoteStatsResults remstats = {.rel = NULL,.att = NULL};
5597 43 : RemoteAttributeMapping *remattrmap = NULL;
5598 43 : int attrcnt = 0;
5599 43 : bool restore_stats = false;
5600 43 : bool ok = false;
5601 : ListCell *lc;
5602 :
5603 43 : schemaname = get_namespace_name(RelationGetNamespace(relation));
5604 43 : relname = RelationGetRelationName(relation);
5605 43 : table = GetForeignTable(RelationGetRelid(relation));
5606 43 : server = GetForeignServer(table->serverid);
5607 :
5608 : /*
5609 : * Check whether the restore_stats option is enabled on the foreign table.
5610 : * If not, silently ignore the foreign table.
5611 : *
5612 : * Server-level options can be overridden by table-level options, so check
5613 : * server-level first.
5614 : */
5615 227 : foreach(lc, server->options)
5616 : {
5617 184 : DefElem *def = (DefElem *) lfirst(lc);
5618 :
5619 184 : if (strcmp(def->defname, "restore_stats") == 0)
5620 : {
5621 0 : restore_stats = defGetBoolean(def);
5622 0 : break;
5623 : }
5624 : }
5625 96 : foreach(lc, table->options)
5626 : {
5627 64 : DefElem *def = (DefElem *) lfirst(lc);
5628 :
5629 64 : if (strcmp(def->defname, "restore_stats") == 0)
5630 : {
5631 11 : restore_stats = defGetBoolean(def);
5632 11 : break;
5633 : }
5634 : }
5635 43 : if (!restore_stats)
5636 32 : return false;
5637 :
5638 : /*
5639 : * We don't currently support statistics import for foreign tables with
5640 : * extended statistics objects.
5641 : */
5642 11 : if (HasRelationExtStatistics(relation))
5643 : {
5644 1 : ereport(WARNING,
5645 : errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
5646 : errmsg("cannot import statistics for foreign table \"%s.%s\" --- this foreign table has extended statistics objects",
5647 : schemaname, relname));
5648 1 : return false;
5649 : }
5650 :
5651 : /*
5652 : * OK, let's do it.
5653 : */
5654 10 : ereport(elevel,
5655 : (errmsg("importing statistics for foreign table \"%s.%s\"",
5656 : schemaname, relname)));
5657 :
5658 10 : ok = fetch_remote_statistics(relation, va_cols,
5659 : table, schemaname, relname,
5660 : &attrcnt, &remattrmap, &remstats);
5661 :
5662 10 : if (ok)
5663 6 : ok = import_fetched_statistics(schemaname, relname,
5664 : attrcnt, remattrmap, &remstats);
5665 :
5666 10 : if (ok)
5667 6 : ereport(elevel,
5668 : (errmsg("finished importing statistics for foreign table \"%s.%s\"",
5669 : schemaname, relname)));
5670 :
5671 10 : PQclear(remstats.rel);
5672 10 : PQclear(remstats.att);
5673 10 : if (remattrmap)
5674 7 : pfree(remattrmap);
5675 :
5676 10 : return ok;
5677 : }
5678 :
5679 : /*
5680 : * Attempt to fetch statistics from a remote server.
5681 : */
5682 : static bool
5683 10 : fetch_remote_statistics(Relation relation,
5684 : List *va_cols,
5685 : ForeignTable *table,
5686 : const char *local_schemaname,
5687 : const char *local_relname,
5688 : int *p_attrcnt,
5689 : RemoteAttributeMapping **p_remattrmap,
5690 : RemoteStatsResults *remstats)
5691 : {
5692 10 : const char *remote_schemaname = NULL;
5693 10 : const char *remote_relname = NULL;
5694 : UserMapping *user;
5695 : PGconn *conn;
5696 10 : PGresult *relstats = NULL;
5697 10 : PGresult *attstats = NULL;
5698 : int server_version_num;
5699 10 : RemoteAttributeMapping *remattrmap = NULL;
5700 10 : int attrcnt = 0;
5701 : char relkind;
5702 : double reltuples;
5703 10 : bool ok = false;
5704 : ListCell *lc;
5705 :
5706 : /*
5707 : * Assume the remote schema/relation names are the same as the local name
5708 : * unless the foreign table's options tell us otherwise.
5709 : */
5710 10 : remote_schemaname = local_schemaname;
5711 10 : remote_relname = local_relname;
5712 30 : foreach(lc, table->options)
5713 : {
5714 20 : DefElem *def = (DefElem *) lfirst(lc);
5715 :
5716 20 : if (strcmp(def->defname, "schema_name") == 0)
5717 0 : remote_schemaname = defGetString(def);
5718 20 : else if (strcmp(def->defname, "table_name") == 0)
5719 10 : remote_relname = defGetString(def);
5720 : }
5721 :
5722 : /*
5723 : * Get connection to the foreign server. Connection manager will
5724 : * establish new connection if necessary.
5725 : */
5726 10 : user = GetUserMapping(GetUserId(), table->serverid);
5727 10 : conn = GetConnection(user, false, NULL);
5728 10 : remstats->server_version_num = server_version_num = PQserverVersion(conn);
5729 :
5730 : /* Fetch relation stats. */
5731 10 : remstats->rel = relstats = fetch_relstats(conn, relation);
5732 :
5733 : /*
5734 : * Verify that the remote table is the sort that can have meaningful stats
5735 : * in pg_stats.
5736 : *
5737 : * Note that while relations of kinds RELKIND_INDEX and
5738 : * RELKIND_PARTITIONED_INDEX can have rows in pg_stats, they obviously
5739 : * can't support a foreign table.
5740 : */
5741 10 : relkind = *PQgetvalue(relstats, 0, RELSTATS_RELKIND);
5742 10 : switch (relkind)
5743 : {
5744 9 : case RELKIND_RELATION:
5745 : case RELKIND_FOREIGN_TABLE:
5746 : case RELKIND_MATVIEW:
5747 : case RELKIND_PARTITIONED_TABLE:
5748 9 : break;
5749 1 : default:
5750 1 : ereport(WARNING,
5751 : errmsg("could not import statistics for foreign table \"%s.%s\" --- remote table \"%s.%s\" is of relkind \"%c\" which cannot have statistics",
5752 : local_schemaname, local_relname,
5753 : remote_schemaname, remote_relname, relkind));
5754 1 : goto fetch_cleanup;
5755 : }
5756 :
5757 : /*
5758 : * If the reltuples value > 0, then then we can expect to find attribute
5759 : * stats for the remote table.
5760 : *
5761 : * In v14 or latter, if a reltuples value is -1, it means the table has
5762 : * never been analyzed, so we wouldn't expect to find the stats for the
5763 : * table; fallback to sampling in that case. If the value is 0, it means
5764 : * it was empty; in which case skip the stats and import relation stats
5765 : * only.
5766 : *
5767 : * In versions prior to v14, a value of 0 was ambiguous; it could mean
5768 : * that the table had never been analyzed, or that it was empty. Either
5769 : * way, we wouldn't expect to find the stats for the table, so we fallback
5770 : * to sampling.
5771 : */
5772 9 : reltuples = strtod(PQgetvalue(relstats, 0, RELSTATS_RELTUPLES), NULL);
5773 9 : if (((server_version_num < 140000) && (reltuples == 0)) ||
5774 9 : ((server_version_num >= 140000) && (reltuples == -1)))
5775 : {
5776 1 : ereport(WARNING,
5777 : errmsg("could not import statistics for foreign table \"%s.%s\" --- remote table \"%s.%s\" has no relation statistics to import",
5778 : local_schemaname, local_relname,
5779 : remote_schemaname, remote_relname));
5780 1 : goto fetch_cleanup;
5781 : }
5782 :
5783 :
5784 8 : if (reltuples > 0)
5785 : {
5786 : StringInfoData column_list;
5787 :
5788 7 : *p_remattrmap = remattrmap = build_remattrmap(relation, va_cols,
5789 : &attrcnt, &column_list);
5790 7 : *p_attrcnt = attrcnt;
5791 :
5792 7 : if (attrcnt > 0)
5793 : {
5794 : /* Fetch attribute stats. */
5795 14 : remstats->att = attstats = fetch_attstats(conn,
5796 : server_version_num,
5797 : remote_schemaname,
5798 : remote_relname,
5799 7 : column_list.data);
5800 :
5801 : /* If any attribute stats are missing, fallback to sampling. */
5802 7 : if (!match_attrmap(attstats,
5803 : local_schemaname, local_relname,
5804 : remote_schemaname, remote_relname,
5805 : attrcnt, remattrmap))
5806 2 : goto fetch_cleanup;
5807 : }
5808 : }
5809 :
5810 6 : ok = true;
5811 :
5812 10 : fetch_cleanup:
5813 10 : ReleaseConnection(conn);
5814 10 : return ok;
5815 : }
5816 :
5817 : /*
5818 : * Attempt to fetch remote relation stats.
5819 : */
5820 : static PGresult *
5821 10 : fetch_relstats(PGconn *conn, Relation relation)
5822 : {
5823 : StringInfoData sql;
5824 : PGresult *res;
5825 :
5826 10 : initStringInfo(&sql);
5827 10 : deparseAnalyzeInfoSql(&sql, relation);
5828 :
5829 10 : res = pgfdw_exec_query(conn, sql.data, NULL);
5830 10 : if (PQresultStatus(res) != PGRES_TUPLES_OK)
5831 0 : pgfdw_report_error(res, conn, sql.data);
5832 :
5833 10 : if (PQntuples(res) != 1 || PQnfields(res) != RELSTATS_NUM_FIELDS)
5834 0 : elog(ERROR, "unexpected result from deparseAnalyzeInfoSql query");
5835 :
5836 10 : return res;
5837 : }
5838 :
5839 : /*
5840 : * Attempt to fetch remote attribute stats.
5841 : */
5842 : static PGresult *
5843 7 : fetch_attstats(PGconn *conn, int server_version_num,
5844 : const char *remote_schemaname, const char *remote_relname,
5845 : const char *column_list)
5846 : {
5847 : StringInfoData sql;
5848 : PGresult *res;
5849 :
5850 7 : initStringInfo(&sql);
5851 7 : appendStringInfoString(&sql,
5852 : "SELECT DISTINCT ON (attname COLLATE \"C\") attname,"
5853 : " null_frac,"
5854 : " avg_width,"
5855 : " n_distinct,"
5856 : " most_common_vals,"
5857 : " most_common_freqs,"
5858 : " histogram_bounds,"
5859 : " correlation,");
5860 :
5861 : /* Elements stats are supported since Postgres 9.2 */
5862 7 : if (server_version_num >= 92000)
5863 7 : appendStringInfoString(&sql,
5864 : " most_common_elems,"
5865 : " most_common_elem_freqs,"
5866 : " elem_count_histogram,");
5867 : else
5868 0 : appendStringInfoString(&sql,
5869 : " NULL, NULL, NULL,");
5870 :
5871 : /* Range stats are supported since Postgres 17 */
5872 7 : if (server_version_num >= 170000)
5873 7 : appendStringInfoString(&sql,
5874 : " range_length_histogram,"
5875 : " range_empty_frac,"
5876 : " range_bounds_histogram");
5877 : else
5878 0 : appendStringInfoString(&sql,
5879 : " NULL, NULL, NULL,");
5880 :
5881 7 : appendStringInfoString(&sql,
5882 : " FROM pg_catalog.pg_stats"
5883 : " WHERE schemaname = ");
5884 7 : deparseStringLiteral(&sql, remote_schemaname);
5885 7 : appendStringInfoString(&sql,
5886 : " AND tablename = ");
5887 7 : deparseStringLiteral(&sql, remote_relname);
5888 7 : appendStringInfo(&sql,
5889 : " AND attname = ANY('%s'::text[])",
5890 : column_list);
5891 :
5892 : /* inherited is supported since Postgres 9.0 */
5893 7 : if (server_version_num >= 90000)
5894 7 : appendStringInfoString(&sql,
5895 : " ORDER BY attname COLLATE \"C\", inherited DESC");
5896 : else
5897 0 : appendStringInfoString(&sql,
5898 : " ORDER BY attname COLLATE \"C\"");
5899 :
5900 7 : res = pgfdw_exec_query(conn, sql.data, NULL);
5901 7 : if (PQresultStatus(res) != PGRES_TUPLES_OK)
5902 0 : pgfdw_report_error(res, conn, sql.data);
5903 :
5904 7 : if (PQnfields(res) != ATTSTATS_NUM_FIELDS)
5905 0 : elog(ERROR, "unexpected result from fetch_attstats query");
5906 :
5907 7 : return res;
5908 : }
5909 :
5910 : /*
5911 : * Build the mapping of local columns to remote columns and create a column
5912 : * list used for constructing the fetch_attstats query.
5913 : */
5914 : static RemoteAttributeMapping *
5915 7 : build_remattrmap(Relation relation, List *va_cols,
5916 : int *p_attrcnt, StringInfo column_list)
5917 : {
5918 7 : TupleDesc tupdesc = RelationGetDescr(relation);
5919 7 : RemoteAttributeMapping *remattrmap = NULL;
5920 7 : int attrcnt = 0;
5921 :
5922 7 : remattrmap = palloc_array(RemoteAttributeMapping, tupdesc->natts);
5923 7 : initStringInfo(column_list);
5924 7 : appendStringInfoChar(column_list, '{');
5925 28 : for (int i = 0; i < tupdesc->natts; i++)
5926 : {
5927 21 : Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
5928 21 : char *attname = NameStr(attr->attname);
5929 21 : AttrNumber attnum = attr->attnum;
5930 : char *remote_attname;
5931 : List *fc_options;
5932 : ListCell *lc;
5933 :
5934 : /* If a list is specified, exclude any attnames not in it. */
5935 21 : if (!attname_in_list(attname, va_cols))
5936 6 : continue;
5937 :
5938 15 : if (!attribute_is_analyzable(relation, attnum, attr, NULL))
5939 0 : continue;
5940 :
5941 : /* If the column_name option is not specified, go with attname. */
5942 15 : remote_attname = attname;
5943 15 : fc_options = GetForeignColumnOptions(RelationGetRelid(relation), attnum);
5944 15 : foreach(lc, fc_options)
5945 : {
5946 5 : DefElem *def = (DefElem *) lfirst(lc);
5947 :
5948 5 : if (strcmp(def->defname, "column_name") == 0)
5949 : {
5950 5 : remote_attname = defGetString(def);
5951 5 : break;
5952 : }
5953 : }
5954 :
5955 15 : if (attrcnt > 0)
5956 8 : appendStringInfoString(column_list, ", ");
5957 15 : appendStringInfoString(column_list, quote_identifier(remote_attname));
5958 :
5959 15 : remattrmap[attrcnt].local_attnum = attnum;
5960 15 : strncpy(remattrmap[attrcnt].local_attname, attname, NAMEDATALEN);
5961 15 : strncpy(remattrmap[attrcnt].remote_attname, remote_attname, NAMEDATALEN);
5962 15 : remattrmap[attrcnt].res_index = -1;
5963 15 : attrcnt++;
5964 : }
5965 7 : appendStringInfoChar(column_list, '}');
5966 :
5967 : /* Sort mapping by remote attribute name if needed. */
5968 7 : if (attrcnt > 1)
5969 5 : qsort(remattrmap, attrcnt, sizeof(RemoteAttributeMapping), remattrmap_cmp);
5970 :
5971 7 : *p_attrcnt = attrcnt;
5972 7 : return remattrmap;
5973 : }
5974 :
5975 : /*
5976 : * Test if an attribute name is in the list.
5977 : *
5978 : * An empty list means that all attribute names are in the list.
5979 : */
5980 : static bool
5981 21 : attname_in_list(const char *attname, List *va_cols)
5982 : {
5983 : ListCell *lc;
5984 :
5985 21 : if (va_cols == NIL)
5986 9 : return true;
5987 :
5988 22 : foreach(lc, va_cols)
5989 : {
5990 16 : char *col = strVal(lfirst(lc));
5991 :
5992 16 : if (strcmp(attname, col) == 0)
5993 6 : return true;
5994 : }
5995 6 : return false;
5996 : }
5997 :
5998 : /*
5999 : * Compare two RemoteAttributeMappings for sorting.
6000 : */
6001 : static int
6002 11 : remattrmap_cmp(const void *v1, const void *v2)
6003 : {
6004 11 : const RemoteAttributeMapping *r1 = v1;
6005 11 : const RemoteAttributeMapping *r2 = v2;
6006 :
6007 11 : return strncmp(r1->remote_attname, r2->remote_attname, NAMEDATALEN);
6008 : }
6009 :
6010 : /*
6011 : * Match local columns to result set rows.
6012 : *
6013 : * As the result set consists of the attribute stats for some/all of distinct
6014 : * mapped remote columns in the RemoteAttributeMapping, every entry in it
6015 : * should have at most one match in the result set; which is also ordered by
6016 : * attname, so we find such pairs by doing a merge join.
6017 : *
6018 : * Returns true if every entry in it has a match, and false if not.
6019 : */
6020 : static bool
6021 7 : match_attrmap(PGresult *res,
6022 : const char *local_schemaname,
6023 : const char *local_relname,
6024 : const char *remote_schemaname,
6025 : const char *remote_relname,
6026 : int attrcnt,
6027 : RemoteAttributeMapping *remattrmap)
6028 : {
6029 7 : int numrows = PQntuples(res);
6030 7 : int row = -1;
6031 :
6032 : /* No work if there are no stats rows. */
6033 7 : if (numrows == 0)
6034 : {
6035 1 : ereport(WARNING,
6036 : errmsg("could not import statistics for foreign table \"%s.%s\" --- remote table \"%s.%s\" has no attribute statistics to import",
6037 : local_schemaname, local_relname,
6038 : remote_schemaname, remote_relname));
6039 1 : return false;
6040 : }
6041 :
6042 : /* Scan all entries in the RemoteAttributeMapping. */
6043 17 : for (int mapidx = 0; mapidx < attrcnt; mapidx++)
6044 : {
6045 : /*
6046 : * First, check whether the entry matches the current stats row, if it
6047 : * is set.
6048 : */
6049 12 : if (row >= 0 &&
6050 6 : strcmp(remattrmap[mapidx].remote_attname,
6051 6 : PQgetvalue(res, row, ATTSTATS_ATTNAME)) == 0)
6052 : {
6053 3 : remattrmap[mapidx].res_index = row;
6054 3 : continue;
6055 : }
6056 :
6057 : /*
6058 : * If we've exhausted all stats rows, it means the stats for the entry
6059 : * are missing.
6060 : */
6061 9 : if (row >= numrows - 1)
6062 : {
6063 1 : ereport(WARNING,
6064 : errmsg("could not import statistics for foreign table \"%s.%s\" --- no attribute statistics found for column \"%s\" of remote table \"%s.%s\"",
6065 : local_schemaname, local_relname,
6066 : remattrmap[mapidx].remote_attname,
6067 : remote_schemaname, remote_relname));
6068 1 : return false;
6069 : }
6070 :
6071 : /* Advance to the next stats row. */
6072 8 : row += 1;
6073 :
6074 : /*
6075 : * If the attname in the entry is less than that in the next stats
6076 : * row, it means the stats for the entry are missing.
6077 : */
6078 8 : if (strcmp(remattrmap[mapidx].remote_attname,
6079 8 : PQgetvalue(res, row, ATTSTATS_ATTNAME)) < 0)
6080 : {
6081 0 : ereport(WARNING,
6082 : errmsg("could not import statistics for foreign table \"%s.%s\" --- no attribute statistics found for column \"%s\" of remote table \"%s.%s\"",
6083 : local_schemaname, local_relname,
6084 : remattrmap[mapidx].remote_attname,
6085 : remote_schemaname, remote_relname));
6086 0 : return false;
6087 : }
6088 :
6089 : /* We should not have got a stats row we didn't expect. */
6090 8 : if (strcmp(remattrmap[mapidx].remote_attname,
6091 8 : PQgetvalue(res, row, ATTSTATS_ATTNAME)) > 0)
6092 0 : elog(ERROR, "unexpected result from fetch_attstats query");
6093 :
6094 : /* We found a match. */
6095 : Assert(strcmp(remattrmap[mapidx].remote_attname,
6096 : PQgetvalue(res, row, ATTSTATS_ATTNAME)) == 0);
6097 8 : remattrmap[mapidx].res_index = row;
6098 : }
6099 :
6100 : /* We should have exhausted all stats rows. */
6101 5 : if (row < numrows - 1)
6102 0 : elog(ERROR, "unexpected result from fetch_attstats query");
6103 :
6104 5 : return true;
6105 : }
6106 :
6107 : /*
6108 : * Import fetched statistics into the local statistics tables.
6109 : */
6110 : static bool
6111 6 : import_fetched_statistics(const char *schemaname,
6112 : const char *relname,
6113 : int attrcnt,
6114 : const RemoteAttributeMapping *remattrmap,
6115 : RemoteStatsResults *remstats)
6116 : {
6117 6 : SPIPlanPtr attimport_plan = NULL;
6118 6 : SPIPlanPtr attclear_plan = NULL;
6119 : Datum values[ATTIMPORT_SQL_NUM_FIELDS];
6120 : char nulls[ATTIMPORT_SQL_NUM_FIELDS];
6121 : int spirc;
6122 6 : bool ok = false;
6123 :
6124 : /* Assign all the invariant parameters common to relation/attribute stats */
6125 6 : values[ATTIMPORT_SQL_VERSION] = Int32GetDatum(remstats->server_version_num);
6126 6 : nulls[ATTIMPORT_SQL_VERSION] = ' ';
6127 :
6128 6 : values[ATTIMPORT_SQL_SCHEMANAME] = CStringGetTextDatum(schemaname);
6129 6 : nulls[ATTIMPORT_SQL_SCHEMANAME] = ' ';
6130 :
6131 6 : values[ATTIMPORT_SQL_RELNAME] = CStringGetTextDatum(relname);
6132 6 : nulls[ATTIMPORT_SQL_RELNAME] = ' ';
6133 :
6134 6 : SPI_connect();
6135 :
6136 : /*
6137 : * We import attribute statistics first, if any, because those are more
6138 : * prone to errors. This avoids making a modification of pg_class that
6139 : * will just get rolled back by a failed attribute import.
6140 : */
6141 6 : if (remstats->att != NULL)
6142 : {
6143 : Assert(PQnfields(remstats->att) == ATTSTATS_NUM_FIELDS);
6144 : Assert(PQntuples(remstats->att) >= 1);
6145 :
6146 5 : attimport_plan = SPI_prepare(attimport_sql, ATTIMPORT_SQL_NUM_FIELDS,
6147 : (Oid *) attimport_argtypes);
6148 5 : if (attimport_plan == NULL)
6149 0 : elog(ERROR, "failed to prepare attimport_sql query");
6150 :
6151 5 : attclear_plan = SPI_prepare(attclear_sql, ATTCLEAR_SQL_NUM_FIELDS,
6152 : (Oid *) attclear_argtypes);
6153 5 : if (attclear_plan == NULL)
6154 0 : elog(ERROR, "failed to prepare attclear_sql query");
6155 :
6156 5 : nulls[ATTIMPORT_SQL_ATTNUM] = ' ';
6157 :
6158 14 : for (int mapidx = 0; mapidx < attrcnt; mapidx++)
6159 : {
6160 9 : int row = remattrmap[mapidx].res_index;
6161 9 : Datum *values2 = values + 1;
6162 9 : char *nulls2 = nulls + 1;
6163 :
6164 : /* All mappings should have been assigned a result set row. */
6165 : Assert(row >= 0);
6166 :
6167 : /*
6168 : * Check for user-requested abort.
6169 : */
6170 9 : CHECK_FOR_INTERRUPTS();
6171 :
6172 : /*
6173 : * First, clear existing attribute stats.
6174 : *
6175 : * We can re-use the values/nulls because the number of parameters
6176 : * is less and the first two params are the same as the second and
6177 : * third ones in attimport_sql.
6178 : */
6179 9 : values2[ATTCLEAR_SQL_ATTNAME] =
6180 9 : CStringGetTextDatum(remattrmap[mapidx].local_attname);
6181 :
6182 9 : spirc = SPI_execute_plan(attclear_plan, values2, nulls2, false, 1);
6183 9 : if (spirc != SPI_OK_SELECT)
6184 0 : elog(ERROR, "failed to execute attclear_sql query for column \"%s\" of foreign table \"%s.%s\"",
6185 : remattrmap[mapidx].local_attname, schemaname, relname);
6186 :
6187 9 : values[ATTIMPORT_SQL_ATTNUM] =
6188 9 : Int16GetDatum(remattrmap[mapidx].local_attnum);
6189 :
6190 : /* Loop through all mappable columns to set remaining arguments */
6191 126 : for (int i = 0; i < NUM_MAPPED_ATTIMPORT_ARGS; i++)
6192 117 : map_field_to_arg(remstats->att, row,
6193 117 : attr_result_arg_map[i].res_field,
6194 117 : attr_result_arg_map[i].arg_num,
6195 : values, nulls);
6196 :
6197 9 : spirc = SPI_execute_plan(attimport_plan, values, nulls, false, 1);
6198 9 : if (spirc != SPI_OK_SELECT)
6199 0 : elog(ERROR, "failed to execute attimport_sql query for column \"%s\" of foreign table \"%s.%s\"",
6200 : remattrmap[mapidx].local_attname, schemaname, relname);
6201 :
6202 9 : if (!import_spi_query_ok())
6203 : {
6204 0 : ereport(WARNING,
6205 : errmsg("could not import statistics for foreign table \"%s.%s\" --- attribute statistics import failed for column \"%s\" of this foreign table",
6206 : schemaname, relname,
6207 : remattrmap[mapidx].local_attname));
6208 0 : goto import_cleanup;
6209 : }
6210 : }
6211 : }
6212 :
6213 : /*
6214 : * Import relation stats. We only perform this once, so there is no point
6215 : * in preparing the statement.
6216 : *
6217 : * We can re-use the values/nulls because the number of parameters is less
6218 : * and the first three params are the same as attimport_sql.
6219 : */
6220 : Assert(remstats->rel != NULL);
6221 : Assert(PQnfields(remstats->rel) == RELSTATS_NUM_FIELDS);
6222 : Assert(PQntuples(remstats->rel) == 1);
6223 6 : map_field_to_arg(remstats->rel, 0, RELSTATS_RELPAGES,
6224 : RELIMPORT_SQL_RELPAGES, values, nulls);
6225 6 : map_field_to_arg(remstats->rel, 0, RELSTATS_RELTUPLES,
6226 : RELIMPORT_SQL_RELTUPLES, values, nulls);
6227 :
6228 6 : spirc = SPI_execute_with_args(relimport_sql,
6229 : RELIMPORT_SQL_NUM_FIELDS,
6230 : (Oid *) relimport_argtypes,
6231 : values, nulls, false, 1);
6232 6 : if (spirc != SPI_OK_SELECT)
6233 0 : elog(ERROR, "failed to execute relimport_sql query for foreign table \"%s.%s\"",
6234 : schemaname, relname);
6235 :
6236 6 : if (!import_spi_query_ok())
6237 : {
6238 0 : ereport(WARNING,
6239 : errmsg("could not import statistics for foreign table \"%s.%s\" --- relation statistics import failed for this foreign table",
6240 : schemaname, relname));
6241 0 : goto import_cleanup;
6242 : }
6243 :
6244 6 : ok = true;
6245 :
6246 6 : import_cleanup:
6247 6 : if (attimport_plan)
6248 5 : SPI_freeplan(attimport_plan);
6249 6 : if (attclear_plan)
6250 5 : SPI_freeplan(attclear_plan);
6251 6 : SPI_finish();
6252 6 : return ok;
6253 : }
6254 :
6255 : /*
6256 : * Move a string value from a result set to a Text value of a Datum array.
6257 : */
6258 : static void
6259 129 : map_field_to_arg(PGresult *res, int row, int field,
6260 : int arg, Datum *values, char *nulls)
6261 : {
6262 129 : if (PQgetisnull(res, row, field))
6263 : {
6264 63 : values[arg] = (Datum) 0;
6265 63 : nulls[arg] = 'n';
6266 : }
6267 : else
6268 : {
6269 66 : const char *s = PQgetvalue(res, row, field);
6270 :
6271 66 : values[arg] = CStringGetTextDatum(s);
6272 66 : nulls[arg] = ' ';
6273 : }
6274 129 : }
6275 :
6276 : /*
6277 : * Check the 1x1 result set of a pg_restore_*_stats() command for success.
6278 : */
6279 : static bool
6280 15 : import_spi_query_ok(void)
6281 : {
6282 : TupleDesc tupdesc;
6283 : Datum dat;
6284 : bool isnull;
6285 :
6286 : Assert(SPI_tuptable != NULL);
6287 : Assert(SPI_processed == 1);
6288 :
6289 15 : tupdesc = SPI_tuptable->tupdesc;
6290 : Assert(tupdesc->natts == 1);
6291 : Assert(TupleDescAttr(tupdesc, 0)->atttypid == BOOLOID);
6292 15 : dat = SPI_getbinval(SPI_tuptable->vals[0], tupdesc, 1, &isnull);
6293 : Assert(!isnull);
6294 :
6295 15 : return DatumGetBool(dat);
6296 : }
6297 :
6298 : /*
6299 : * Import a foreign schema
6300 : */
6301 : static List *
6302 10 : postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
6303 : {
6304 10 : List *commands = NIL;
6305 10 : bool import_collate = true;
6306 10 : bool import_default = false;
6307 10 : bool import_generated = true;
6308 10 : bool import_not_null = true;
6309 : ForeignServer *server;
6310 : UserMapping *mapping;
6311 : PGconn *conn;
6312 : StringInfoData buf;
6313 : PGresult *res;
6314 : int numrows,
6315 : i;
6316 : ListCell *lc;
6317 :
6318 : /* Parse statement options */
6319 14 : foreach(lc, stmt->options)
6320 : {
6321 4 : DefElem *def = (DefElem *) lfirst(lc);
6322 :
6323 4 : if (strcmp(def->defname, "import_collate") == 0)
6324 1 : import_collate = defGetBoolean(def);
6325 3 : else if (strcmp(def->defname, "import_default") == 0)
6326 1 : import_default = defGetBoolean(def);
6327 2 : else if (strcmp(def->defname, "import_generated") == 0)
6328 1 : import_generated = defGetBoolean(def);
6329 1 : else if (strcmp(def->defname, "import_not_null") == 0)
6330 1 : import_not_null = defGetBoolean(def);
6331 : else
6332 0 : ereport(ERROR,
6333 : (errcode(ERRCODE_FDW_INVALID_OPTION_NAME),
6334 : errmsg("invalid option \"%s\"", def->defname)));
6335 : }
6336 :
6337 : /*
6338 : * Get connection to the foreign server. Connection manager will
6339 : * establish new connection if necessary.
6340 : */
6341 10 : server = GetForeignServer(serverOid);
6342 10 : mapping = GetUserMapping(GetUserId(), server->serverid);
6343 10 : conn = GetConnection(mapping, false, NULL);
6344 :
6345 : /* Don't attempt to import collation if remote server hasn't got it */
6346 10 : if (PQserverVersion(conn) < 90100)
6347 0 : import_collate = false;
6348 :
6349 : /* Create workspace for strings */
6350 10 : initStringInfo(&buf);
6351 :
6352 : /* Check that the schema really exists */
6353 10 : appendStringInfoString(&buf, "SELECT 1 FROM pg_catalog.pg_namespace WHERE nspname = ");
6354 10 : deparseStringLiteral(&buf, stmt->remote_schema);
6355 :
6356 10 : res = pgfdw_exec_query(conn, buf.data, NULL);
6357 10 : if (PQresultStatus(res) != PGRES_TUPLES_OK)
6358 0 : pgfdw_report_error(res, conn, buf.data);
6359 :
6360 10 : if (PQntuples(res) != 1)
6361 1 : ereport(ERROR,
6362 : (errcode(ERRCODE_FDW_SCHEMA_NOT_FOUND),
6363 : errmsg("schema \"%s\" is not present on foreign server \"%s\"",
6364 : stmt->remote_schema, server->servername)));
6365 :
6366 9 : PQclear(res);
6367 9 : resetStringInfo(&buf);
6368 :
6369 : /*
6370 : * Fetch all table data from this schema, possibly restricted by EXCEPT or
6371 : * LIMIT TO. (We don't actually need to pay any attention to EXCEPT/LIMIT
6372 : * TO here, because the core code will filter the statements we return
6373 : * according to those lists anyway. But it should save a few cycles to
6374 : * not process excluded tables in the first place.)
6375 : *
6376 : * Import table data for partitions only when they are explicitly
6377 : * specified in LIMIT TO clause. Otherwise ignore them and only include
6378 : * the definitions of the root partitioned tables to allow access to the
6379 : * complete remote data set locally in the schema imported.
6380 : *
6381 : * Note: because we run the connection with search_path restricted to
6382 : * pg_catalog, the format_type() and pg_get_expr() outputs will always
6383 : * include a schema name for types/functions in other schemas, which is
6384 : * what we want.
6385 : */
6386 9 : appendStringInfoString(&buf,
6387 : "SELECT relname, "
6388 : " attname, "
6389 : " format_type(atttypid, atttypmod), "
6390 : " attnotnull, "
6391 : " pg_get_expr(adbin, adrelid), ");
6392 :
6393 : /* Generated columns are supported since Postgres 12 */
6394 9 : if (PQserverVersion(conn) >= 120000)
6395 9 : appendStringInfoString(&buf,
6396 : " attgenerated, ");
6397 : else
6398 0 : appendStringInfoString(&buf,
6399 : " NULL, ");
6400 :
6401 9 : if (import_collate)
6402 8 : appendStringInfoString(&buf,
6403 : " collname, "
6404 : " collnsp.nspname ");
6405 : else
6406 1 : appendStringInfoString(&buf,
6407 : " NULL, NULL ");
6408 :
6409 9 : appendStringInfoString(&buf,
6410 : "FROM pg_class c "
6411 : " JOIN pg_namespace n ON "
6412 : " relnamespace = n.oid "
6413 : " LEFT JOIN pg_attribute a ON "
6414 : " attrelid = c.oid AND attnum > 0 "
6415 : " AND NOT attisdropped "
6416 : " LEFT JOIN pg_attrdef ad ON "
6417 : " adrelid = c.oid AND adnum = attnum ");
6418 :
6419 9 : if (import_collate)
6420 8 : appendStringInfoString(&buf,
6421 : " LEFT JOIN pg_collation coll ON "
6422 : " coll.oid = attcollation "
6423 : " LEFT JOIN pg_namespace collnsp ON "
6424 : " collnsp.oid = collnamespace ");
6425 :
6426 9 : appendStringInfoString(&buf,
6427 : "WHERE c.relkind IN ("
6428 : CppAsString2(RELKIND_RELATION) ","
6429 : CppAsString2(RELKIND_VIEW) ","
6430 : CppAsString2(RELKIND_FOREIGN_TABLE) ","
6431 : CppAsString2(RELKIND_MATVIEW) ","
6432 : CppAsString2(RELKIND_PARTITIONED_TABLE) ") "
6433 : " AND n.nspname = ");
6434 9 : deparseStringLiteral(&buf, stmt->remote_schema);
6435 :
6436 : /* Partitions are supported since Postgres 10 */
6437 9 : if (PQserverVersion(conn) >= 100000 &&
6438 9 : stmt->list_type != FDW_IMPORT_SCHEMA_LIMIT_TO)
6439 5 : appendStringInfoString(&buf, " AND NOT c.relispartition ");
6440 :
6441 : /* Apply restrictions for LIMIT TO and EXCEPT */
6442 9 : if (stmt->list_type == FDW_IMPORT_SCHEMA_LIMIT_TO ||
6443 5 : stmt->list_type == FDW_IMPORT_SCHEMA_EXCEPT)
6444 : {
6445 5 : bool first_item = true;
6446 :
6447 5 : appendStringInfoString(&buf, " AND c.relname ");
6448 5 : if (stmt->list_type == FDW_IMPORT_SCHEMA_EXCEPT)
6449 1 : appendStringInfoString(&buf, "NOT ");
6450 5 : appendStringInfoString(&buf, "IN (");
6451 :
6452 : /* Append list of table names within IN clause */
6453 15 : foreach(lc, stmt->table_list)
6454 : {
6455 10 : RangeVar *rv = (RangeVar *) lfirst(lc);
6456 :
6457 10 : if (first_item)
6458 5 : first_item = false;
6459 : else
6460 5 : appendStringInfoString(&buf, ", ");
6461 10 : deparseStringLiteral(&buf, rv->relname);
6462 : }
6463 5 : appendStringInfoChar(&buf, ')');
6464 : }
6465 :
6466 : /* Append ORDER BY at the end of query to ensure output ordering */
6467 9 : appendStringInfoString(&buf, " ORDER BY c.relname, a.attnum");
6468 :
6469 : /* Fetch the data */
6470 9 : res = pgfdw_exec_query(conn, buf.data, NULL);
6471 9 : if (PQresultStatus(res) != PGRES_TUPLES_OK)
6472 0 : pgfdw_report_error(res, conn, buf.data);
6473 :
6474 : /* Process results */
6475 9 : numrows = PQntuples(res);
6476 : /* note: incrementation of i happens in inner loop's while() test */
6477 47 : for (i = 0; i < numrows;)
6478 : {
6479 38 : char *tablename = PQgetvalue(res, i, 0);
6480 38 : bool first_item = true;
6481 :
6482 38 : resetStringInfo(&buf);
6483 38 : appendStringInfo(&buf, "CREATE FOREIGN TABLE %s (\n",
6484 : quote_identifier(tablename));
6485 :
6486 : /* Scan all rows for this table */
6487 : do
6488 : {
6489 : char *attname;
6490 : char *typename;
6491 : char *attnotnull;
6492 : char *attgenerated;
6493 : char *attdefault;
6494 : char *collname;
6495 : char *collnamespace;
6496 :
6497 : /* If table has no columns, we'll see nulls here */
6498 75 : if (PQgetisnull(res, i, 1))
6499 5 : continue;
6500 :
6501 70 : attname = PQgetvalue(res, i, 1);
6502 70 : typename = PQgetvalue(res, i, 2);
6503 70 : attnotnull = PQgetvalue(res, i, 3);
6504 70 : attdefault = PQgetisnull(res, i, 4) ? NULL :
6505 15 : PQgetvalue(res, i, 4);
6506 70 : attgenerated = PQgetisnull(res, i, 5) ? NULL :
6507 70 : PQgetvalue(res, i, 5);
6508 70 : collname = PQgetisnull(res, i, 6) ? NULL :
6509 19 : PQgetvalue(res, i, 6);
6510 70 : collnamespace = PQgetisnull(res, i, 7) ? NULL :
6511 19 : PQgetvalue(res, i, 7);
6512 :
6513 70 : if (first_item)
6514 33 : first_item = false;
6515 : else
6516 37 : appendStringInfoString(&buf, ",\n");
6517 :
6518 : /* Print column name and type */
6519 70 : appendStringInfo(&buf, " %s %s",
6520 : quote_identifier(attname),
6521 : typename);
6522 :
6523 : /*
6524 : * Add column_name option so that renaming the foreign table's
6525 : * column doesn't break the association to the underlying column.
6526 : */
6527 70 : appendStringInfoString(&buf, " OPTIONS (column_name ");
6528 70 : deparseStringLiteral(&buf, attname);
6529 70 : appendStringInfoChar(&buf, ')');
6530 :
6531 : /* Add COLLATE if needed */
6532 70 : if (import_collate && collname != NULL && collnamespace != NULL)
6533 19 : appendStringInfo(&buf, " COLLATE %s.%s",
6534 : quote_identifier(collnamespace),
6535 : quote_identifier(collname));
6536 :
6537 : /* Add DEFAULT if needed */
6538 70 : if (import_default && attdefault != NULL &&
6539 3 : (!attgenerated || !attgenerated[0]))
6540 2 : appendStringInfo(&buf, " DEFAULT %s", attdefault);
6541 :
6542 : /* Add GENERATED if needed */
6543 70 : if (import_generated && attgenerated != NULL &&
6544 57 : attgenerated[0] == ATTRIBUTE_GENERATED_STORED)
6545 : {
6546 : Assert(attdefault != NULL);
6547 4 : appendStringInfo(&buf,
6548 : " GENERATED ALWAYS AS (%s) STORED",
6549 : attdefault);
6550 : }
6551 :
6552 : /* Add NOT NULL if needed */
6553 70 : if (import_not_null && attnotnull[0] == 't')
6554 4 : appendStringInfoString(&buf, " NOT NULL");
6555 : }
6556 75 : while (++i < numrows &&
6557 66 : strcmp(PQgetvalue(res, i, 0), tablename) == 0);
6558 :
6559 : /*
6560 : * Add server name and table-level options. We specify remote schema
6561 : * and table name as options (the latter to ensure that renaming the
6562 : * foreign table doesn't break the association).
6563 : */
6564 38 : appendStringInfo(&buf, "\n) SERVER %s\nOPTIONS (",
6565 38 : quote_identifier(server->servername));
6566 :
6567 38 : appendStringInfoString(&buf, "schema_name ");
6568 38 : deparseStringLiteral(&buf, stmt->remote_schema);
6569 38 : appendStringInfoString(&buf, ", table_name ");
6570 38 : deparseStringLiteral(&buf, tablename);
6571 :
6572 38 : appendStringInfoString(&buf, ");");
6573 :
6574 38 : commands = lappend(commands, pstrdup(buf.data));
6575 : }
6576 9 : PQclear(res);
6577 :
6578 9 : ReleaseConnection(conn);
6579 :
6580 9 : return commands;
6581 : }
6582 :
6583 : /*
6584 : * Check if reltarget is safe enough to push down semi-join. Reltarget is not
6585 : * safe, if it contains references to inner rel relids, which do not belong to
6586 : * outer rel.
6587 : */
6588 : static bool
6589 64 : semijoin_target_ok(PlannerInfo *root, RelOptInfo *joinrel, RelOptInfo *outerrel, RelOptInfo *innerrel)
6590 : {
6591 : List *vars;
6592 : ListCell *lc;
6593 64 : bool ok = true;
6594 :
6595 : Assert(joinrel->reltarget);
6596 :
6597 64 : vars = pull_var_clause((Node *) joinrel->reltarget->exprs, PVC_INCLUDE_PLACEHOLDERS);
6598 :
6599 443 : foreach(lc, vars)
6600 : {
6601 394 : Var *var = (Var *) lfirst(lc);
6602 :
6603 394 : if (!IsA(var, Var))
6604 0 : continue;
6605 :
6606 394 : if (bms_is_member(var->varno, innerrel->relids))
6607 : {
6608 : /*
6609 : * The planner can create semi-join, which refers to inner rel
6610 : * vars in its target list. However, we deparse semi-join as an
6611 : * exists() subquery, so can't handle references to inner rel in
6612 : * the target list.
6613 : */
6614 : Assert(!bms_is_member(var->varno, outerrel->relids));
6615 15 : ok = false;
6616 15 : break;
6617 : }
6618 : }
6619 64 : return ok;
6620 : }
6621 :
6622 : /*
6623 : * Assess whether the join between inner and outer relations can be pushed down
6624 : * to the foreign server. As a side effect, save information we obtain in this
6625 : * function to PgFdwRelationInfo passed in.
6626 : */
6627 : static bool
6628 396 : foreign_join_ok(PlannerInfo *root, RelOptInfo *joinrel, JoinType jointype,
6629 : RelOptInfo *outerrel, RelOptInfo *innerrel,
6630 : JoinPathExtraData *extra)
6631 : {
6632 : PgFdwRelationInfo *fpinfo;
6633 : PgFdwRelationInfo *fpinfo_o;
6634 : PgFdwRelationInfo *fpinfo_i;
6635 : ListCell *lc;
6636 : List *joinclauses;
6637 :
6638 : /*
6639 : * We support pushing down INNER, LEFT, RIGHT, FULL OUTER and SEMI joins.
6640 : * Constructing queries representing ANTI joins is hard, hence not
6641 : * considered right now.
6642 : */
6643 396 : if (jointype != JOIN_INNER && jointype != JOIN_LEFT &&
6644 129 : jointype != JOIN_RIGHT && jointype != JOIN_FULL &&
6645 : jointype != JOIN_SEMI)
6646 19 : return false;
6647 :
6648 : /*
6649 : * We can't push down semi-join if its reltarget is not safe
6650 : */
6651 377 : if ((jointype == JOIN_SEMI) && !semijoin_target_ok(root, joinrel, outerrel, innerrel))
6652 15 : return false;
6653 :
6654 : /*
6655 : * If either of the joining relations is marked as unsafe to pushdown, the
6656 : * join can not be pushed down.
6657 : */
6658 362 : fpinfo = (PgFdwRelationInfo *) joinrel->fdw_private;
6659 362 : fpinfo_o = (PgFdwRelationInfo *) outerrel->fdw_private;
6660 362 : fpinfo_i = (PgFdwRelationInfo *) innerrel->fdw_private;
6661 362 : if (!fpinfo_o || !fpinfo_o->pushdown_safe ||
6662 357 : !fpinfo_i || !fpinfo_i->pushdown_safe)
6663 5 : return false;
6664 :
6665 : /*
6666 : * If joining relations have local conditions, those conditions are
6667 : * required to be applied before joining the relations. Hence the join can
6668 : * not be pushed down.
6669 : */
6670 357 : if (fpinfo_o->local_conds || fpinfo_i->local_conds)
6671 9 : return false;
6672 :
6673 : /*
6674 : * Merge FDW options. We might be tempted to do this after we have deemed
6675 : * the foreign join to be OK. But we must do this beforehand so that we
6676 : * know which quals can be evaluated on the foreign server, which might
6677 : * depend on shippable_extensions.
6678 : */
6679 348 : fpinfo->server = fpinfo_o->server;
6680 348 : merge_fdw_options(fpinfo, fpinfo_o, fpinfo_i);
6681 :
6682 : /*
6683 : * Separate restrict list into join quals and pushed-down (other) quals.
6684 : *
6685 : * Join quals belonging to an outer join must all be shippable, else we
6686 : * cannot execute the join remotely. Add such quals to 'joinclauses'.
6687 : *
6688 : * Add other quals to fpinfo->remote_conds if they are shippable, else to
6689 : * fpinfo->local_conds. In an inner join it's okay to execute conditions
6690 : * either locally or remotely; the same is true for pushed-down conditions
6691 : * at an outer join.
6692 : *
6693 : * Note we might return failure after having already scribbled on
6694 : * fpinfo->remote_conds and fpinfo->local_conds. That's okay because we
6695 : * won't consult those lists again if we deem the join unshippable.
6696 : */
6697 348 : joinclauses = NIL;
6698 691 : foreach(lc, extra->restrictlist)
6699 : {
6700 346 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
6701 346 : bool is_remote_clause = is_foreign_expr(root, joinrel,
6702 : rinfo->clause);
6703 :
6704 346 : if (IS_OUTER_JOIN(jointype) &&
6705 129 : !RINFO_IS_PUSHED_DOWN(rinfo, joinrel->relids))
6706 : {
6707 113 : if (!is_remote_clause)
6708 3 : return false;
6709 110 : joinclauses = lappend(joinclauses, rinfo);
6710 : }
6711 : else
6712 : {
6713 233 : if (is_remote_clause)
6714 221 : fpinfo->remote_conds = lappend(fpinfo->remote_conds, rinfo);
6715 : else
6716 12 : fpinfo->local_conds = lappend(fpinfo->local_conds, rinfo);
6717 : }
6718 : }
6719 :
6720 : /*
6721 : * deparseExplicitTargetList() isn't smart enough to handle anything other
6722 : * than a Var. In particular, if there's some PlaceHolderVar that would
6723 : * need to be evaluated within this join tree (because there's an upper
6724 : * reference to a quantity that may go to NULL as a result of an outer
6725 : * join), then we can't try to push the join down because we'll fail when
6726 : * we get to deparseExplicitTargetList(). However, a PlaceHolderVar that
6727 : * needs to be evaluated *at the top* of this join tree is OK, because we
6728 : * can do that locally after fetching the results from the remote side.
6729 : */
6730 348 : foreach(lc, root->placeholder_list)
6731 : {
6732 11 : PlaceHolderInfo *phinfo = lfirst(lc);
6733 : Relids relids;
6734 :
6735 : /* PlaceHolderInfo refers to parent relids, not child relids. */
6736 11 : relids = IS_OTHER_REL(joinrel) ?
6737 22 : joinrel->top_parent_relids : joinrel->relids;
6738 :
6739 22 : if (bms_is_subset(phinfo->ph_eval_at, relids) &&
6740 11 : bms_nonempty_difference(relids, phinfo->ph_eval_at))
6741 8 : return false;
6742 : }
6743 :
6744 : /* Save the join clauses, for later use. */
6745 337 : fpinfo->joinclauses = joinclauses;
6746 :
6747 337 : fpinfo->outerrel = outerrel;
6748 337 : fpinfo->innerrel = innerrel;
6749 337 : fpinfo->jointype = jointype;
6750 :
6751 : /*
6752 : * By default, both the input relations are not required to be deparsed as
6753 : * subqueries, but there might be some relations covered by the input
6754 : * relations that are required to be deparsed as subqueries, so save the
6755 : * relids of those relations for later use by the deparser.
6756 : */
6757 337 : fpinfo->make_outerrel_subquery = false;
6758 337 : fpinfo->make_innerrel_subquery = false;
6759 : Assert(bms_is_subset(fpinfo_o->lower_subquery_rels, outerrel->relids));
6760 : Assert(bms_is_subset(fpinfo_i->lower_subquery_rels, innerrel->relids));
6761 674 : fpinfo->lower_subquery_rels = bms_union(fpinfo_o->lower_subquery_rels,
6762 337 : fpinfo_i->lower_subquery_rels);
6763 674 : fpinfo->hidden_subquery_rels = bms_union(fpinfo_o->hidden_subquery_rels,
6764 337 : fpinfo_i->hidden_subquery_rels);
6765 :
6766 : /*
6767 : * Pull the other remote conditions from the joining relations into join
6768 : * clauses or other remote clauses (remote_conds) of this relation
6769 : * wherever possible. This avoids building subqueries at every join step.
6770 : *
6771 : * For an inner join, clauses from both the relations are added to the
6772 : * other remote clauses. For LEFT and RIGHT OUTER join, the clauses from
6773 : * the outer side are added to remote_conds since those can be evaluated
6774 : * after the join is evaluated. The clauses from inner side are added to
6775 : * the joinclauses, since they need to be evaluated while constructing the
6776 : * join.
6777 : *
6778 : * For SEMI-JOIN clauses from inner relation can not be added to
6779 : * remote_conds, but should be treated as join clauses (as they are
6780 : * deparsed to EXISTS subquery, where inner relation can be referred). A
6781 : * list of relation ids, which can't be referred to from higher levels, is
6782 : * preserved as a hidden_subquery_rels list.
6783 : *
6784 : * For a FULL OUTER JOIN, the other clauses from either relation can not
6785 : * be added to the joinclauses or remote_conds, since each relation acts
6786 : * as an outer relation for the other.
6787 : *
6788 : * The joining sides can not have local conditions, thus no need to test
6789 : * shippability of the clauses being pulled up.
6790 : */
6791 337 : switch (jointype)
6792 : {
6793 191 : case JOIN_INNER:
6794 382 : fpinfo->remote_conds = list_concat(fpinfo->remote_conds,
6795 191 : fpinfo_i->remote_conds);
6796 382 : fpinfo->remote_conds = list_concat(fpinfo->remote_conds,
6797 191 : fpinfo_o->remote_conds);
6798 191 : break;
6799 :
6800 60 : case JOIN_LEFT:
6801 :
6802 : /*
6803 : * When semi-join is involved in the inner or outer part of the
6804 : * left join, it's deparsed as a subquery, and we can't refer to
6805 : * its vars on the upper level.
6806 : */
6807 60 : if (bms_is_empty(fpinfo_i->hidden_subquery_rels))
6808 56 : fpinfo->joinclauses = list_concat(fpinfo->joinclauses,
6809 56 : fpinfo_i->remote_conds);
6810 60 : if (bms_is_empty(fpinfo_o->hidden_subquery_rels))
6811 60 : fpinfo->remote_conds = list_concat(fpinfo->remote_conds,
6812 60 : fpinfo_o->remote_conds);
6813 60 : break;
6814 :
6815 0 : case JOIN_RIGHT:
6816 :
6817 : /*
6818 : * When semi-join is involved in the inner or outer part of the
6819 : * right join, it's deparsed as a subquery, and we can't refer to
6820 : * its vars on the upper level.
6821 : */
6822 0 : if (bms_is_empty(fpinfo_o->hidden_subquery_rels))
6823 0 : fpinfo->joinclauses = list_concat(fpinfo->joinclauses,
6824 0 : fpinfo_o->remote_conds);
6825 0 : if (bms_is_empty(fpinfo_i->hidden_subquery_rels))
6826 0 : fpinfo->remote_conds = list_concat(fpinfo->remote_conds,
6827 0 : fpinfo_i->remote_conds);
6828 0 : break;
6829 :
6830 44 : case JOIN_SEMI:
6831 88 : fpinfo->joinclauses = list_concat(fpinfo->joinclauses,
6832 44 : fpinfo_i->remote_conds);
6833 88 : fpinfo->joinclauses = list_concat(fpinfo->joinclauses,
6834 44 : fpinfo->remote_conds);
6835 44 : fpinfo->remote_conds = list_copy(fpinfo_o->remote_conds);
6836 88 : fpinfo->hidden_subquery_rels = bms_union(fpinfo->hidden_subquery_rels,
6837 44 : innerrel->relids);
6838 44 : break;
6839 :
6840 42 : case JOIN_FULL:
6841 :
6842 : /*
6843 : * In this case, if any of the input relations has conditions, we
6844 : * need to deparse that relation as a subquery so that the
6845 : * conditions can be evaluated before the join. Remember it in
6846 : * the fpinfo of this relation so that the deparser can take
6847 : * appropriate action. Also, save the relids of base relations
6848 : * covered by that relation for later use by the deparser.
6849 : */
6850 42 : if (fpinfo_o->remote_conds)
6851 : {
6852 14 : fpinfo->make_outerrel_subquery = true;
6853 14 : fpinfo->lower_subquery_rels =
6854 14 : bms_add_members(fpinfo->lower_subquery_rels,
6855 14 : outerrel->relids);
6856 : }
6857 42 : if (fpinfo_i->remote_conds)
6858 : {
6859 14 : fpinfo->make_innerrel_subquery = true;
6860 14 : fpinfo->lower_subquery_rels =
6861 14 : bms_add_members(fpinfo->lower_subquery_rels,
6862 14 : innerrel->relids);
6863 : }
6864 42 : break;
6865 :
6866 0 : default:
6867 : /* Should not happen, we have just checked this above */
6868 0 : elog(ERROR, "unsupported join type %d", jointype);
6869 : }
6870 :
6871 : /*
6872 : * For an inner join, all restrictions can be treated alike. Treating the
6873 : * pushed down conditions as join conditions allows a top level full outer
6874 : * join to be deparsed without requiring subqueries.
6875 : */
6876 337 : if (jointype == JOIN_INNER)
6877 : {
6878 : Assert(!fpinfo->joinclauses);
6879 191 : fpinfo->joinclauses = fpinfo->remote_conds;
6880 191 : fpinfo->remote_conds = NIL;
6881 : }
6882 146 : else if (jointype == JOIN_LEFT || jointype == JOIN_RIGHT || jointype == JOIN_FULL)
6883 : {
6884 : /*
6885 : * Conditions, generated from semi-joins, should be evaluated before
6886 : * LEFT/RIGHT/FULL join.
6887 : */
6888 102 : if (!bms_is_empty(fpinfo_o->hidden_subquery_rels))
6889 : {
6890 0 : fpinfo->make_outerrel_subquery = true;
6891 0 : fpinfo->lower_subquery_rels = bms_add_members(fpinfo->lower_subquery_rels, outerrel->relids);
6892 : }
6893 :
6894 102 : if (!bms_is_empty(fpinfo_i->hidden_subquery_rels))
6895 : {
6896 4 : fpinfo->make_innerrel_subquery = true;
6897 4 : fpinfo->lower_subquery_rels = bms_add_members(fpinfo->lower_subquery_rels, innerrel->relids);
6898 : }
6899 : }
6900 :
6901 : /* Mark that this join can be pushed down safely */
6902 337 : fpinfo->pushdown_safe = true;
6903 :
6904 : /* Get user mapping */
6905 337 : if (fpinfo->use_remote_estimate)
6906 : {
6907 225 : if (fpinfo_o->use_remote_estimate)
6908 159 : fpinfo->user = fpinfo_o->user;
6909 : else
6910 66 : fpinfo->user = fpinfo_i->user;
6911 : }
6912 : else
6913 112 : fpinfo->user = NULL;
6914 :
6915 : /*
6916 : * Set # of retrieved rows and cached relation costs to some negative
6917 : * value, so that we can detect when they are set to some sensible values,
6918 : * during one (usually the first) of the calls to estimate_path_cost_size.
6919 : */
6920 337 : fpinfo->retrieved_rows = -1;
6921 337 : fpinfo->rel_startup_cost = -1;
6922 337 : fpinfo->rel_total_cost = -1;
6923 :
6924 : /*
6925 : * Set the string describing this join relation to be used in EXPLAIN
6926 : * output of corresponding ForeignScan. Note that the decoration we add
6927 : * to the base relation names mustn't include any digits, or it'll confuse
6928 : * postgresExplainForeignScan.
6929 : */
6930 337 : fpinfo->relation_name = psprintf("(%s) %s JOIN (%s)",
6931 : fpinfo_o->relation_name,
6932 : get_jointype_name(fpinfo->jointype),
6933 : fpinfo_i->relation_name);
6934 :
6935 : /*
6936 : * Set the relation index. This is defined as the position of this
6937 : * joinrel in the join_rel_list list plus the length of the rtable list.
6938 : * Note that since this joinrel is at the end of the join_rel_list list
6939 : * when we are called, we can get the position by list_length.
6940 : */
6941 : Assert(fpinfo->relation_index == 0); /* shouldn't be set yet */
6942 337 : fpinfo->relation_index =
6943 337 : list_length(root->parse->rtable) + list_length(root->join_rel_list);
6944 :
6945 337 : return true;
6946 : }
6947 :
6948 : static void
6949 1551 : add_paths_with_pathkeys_for_rel(PlannerInfo *root, RelOptInfo *rel,
6950 : Path *epq_path, List *restrictlist)
6951 : {
6952 1551 : List *useful_pathkeys_list = NIL; /* List of all pathkeys */
6953 : ListCell *lc;
6954 :
6955 1551 : useful_pathkeys_list = get_useful_pathkeys_for_relation(root, rel);
6956 :
6957 : /*
6958 : * Before creating sorted paths, arrange for the passed-in EPQ path, if
6959 : * any, to return columns needed by the parent ForeignScan node so that
6960 : * they will propagate up through Sort nodes injected below, if necessary.
6961 : */
6962 1551 : if (epq_path != NULL && useful_pathkeys_list != NIL)
6963 : {
6964 34 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private;
6965 34 : PathTarget *target = copy_pathtarget(epq_path->pathtarget);
6966 :
6967 : /* Include columns required for evaluating PHVs in the tlist. */
6968 34 : add_new_columns_to_pathtarget(target,
6969 34 : pull_var_clause((Node *) target->exprs,
6970 : PVC_RECURSE_PLACEHOLDERS));
6971 :
6972 : /* Include columns required for evaluating the local conditions. */
6973 37 : foreach(lc, fpinfo->local_conds)
6974 : {
6975 3 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
6976 :
6977 3 : add_new_columns_to_pathtarget(target,
6978 3 : pull_var_clause((Node *) rinfo->clause,
6979 : PVC_RECURSE_PLACEHOLDERS));
6980 : }
6981 :
6982 : /*
6983 : * If we have added any new columns, adjust the tlist of the EPQ path.
6984 : *
6985 : * Note: the plan created using this path will only be used to execute
6986 : * EPQ checks, where accuracy of the plan cost and width estimates
6987 : * would not be important, so we do not do set_pathtarget_cost_width()
6988 : * for the new pathtarget here. See also postgresGetForeignPlan().
6989 : */
6990 34 : if (list_length(target->exprs) > list_length(epq_path->pathtarget->exprs))
6991 : {
6992 : /* The EPQ path is a join path, so it is projection-capable. */
6993 : Assert(is_projection_capable_path(epq_path));
6994 :
6995 : /*
6996 : * Use create_projection_path() here, so as to avoid modifying it
6997 : * in place.
6998 : */
6999 4 : epq_path = (Path *) create_projection_path(root,
7000 : rel,
7001 : epq_path,
7002 : target);
7003 : }
7004 : }
7005 :
7006 : /* Create one path for each set of pathkeys we found above. */
7007 2251 : foreach(lc, useful_pathkeys_list)
7008 : {
7009 : double rows;
7010 : int width;
7011 : int disabled_nodes;
7012 : Cost startup_cost;
7013 : Cost total_cost;
7014 700 : List *useful_pathkeys = lfirst(lc);
7015 : Path *sorted_epq_path;
7016 :
7017 700 : estimate_path_cost_size(root, rel, NIL, useful_pathkeys, NULL,
7018 : &rows, &width, &disabled_nodes,
7019 : &startup_cost, &total_cost);
7020 :
7021 : /*
7022 : * The EPQ path must be at least as well sorted as the path itself, in
7023 : * case it gets used as input to a mergejoin.
7024 : */
7025 700 : sorted_epq_path = epq_path;
7026 700 : if (sorted_epq_path != NULL &&
7027 34 : !pathkeys_contained_in(useful_pathkeys,
7028 : sorted_epq_path->pathkeys))
7029 : sorted_epq_path = (Path *)
7030 26 : create_sort_path(root,
7031 : rel,
7032 : sorted_epq_path,
7033 : useful_pathkeys,
7034 : -1.0);
7035 :
7036 700 : if (IS_SIMPLE_REL(rel))
7037 431 : add_path(rel, (Path *)
7038 431 : create_foreignscan_path(root, rel,
7039 : NULL,
7040 : rows,
7041 : disabled_nodes,
7042 : startup_cost,
7043 : total_cost,
7044 : useful_pathkeys,
7045 : rel->lateral_relids,
7046 : sorted_epq_path,
7047 : NIL, /* no fdw_restrictinfo
7048 : * list */
7049 : NIL));
7050 : else
7051 269 : add_path(rel, (Path *)
7052 269 : create_foreign_join_path(root, rel,
7053 : NULL,
7054 : rows,
7055 : disabled_nodes,
7056 : startup_cost,
7057 : total_cost,
7058 : useful_pathkeys,
7059 : rel->lateral_relids,
7060 : sorted_epq_path,
7061 : restrictlist,
7062 : NIL));
7063 : }
7064 1551 : }
7065 :
7066 : /*
7067 : * Parse options from foreign server and apply them to fpinfo.
7068 : *
7069 : * New options might also require tweaking merge_fdw_options().
7070 : */
7071 : static void
7072 1216 : apply_server_options(PgFdwRelationInfo *fpinfo)
7073 : {
7074 : ListCell *lc;
7075 :
7076 5168 : foreach(lc, fpinfo->server->options)
7077 : {
7078 3952 : DefElem *def = (DefElem *) lfirst(lc);
7079 :
7080 3952 : if (strcmp(def->defname, "use_remote_estimate") == 0)
7081 135 : fpinfo->use_remote_estimate = defGetBoolean(def);
7082 3817 : else if (strcmp(def->defname, "fdw_startup_cost") == 0)
7083 6 : (void) parse_real(defGetString(def), &fpinfo->fdw_startup_cost, 0,
7084 : NULL);
7085 3811 : else if (strcmp(def->defname, "fdw_tuple_cost") == 0)
7086 2 : (void) parse_real(defGetString(def), &fpinfo->fdw_tuple_cost, 0,
7087 : NULL);
7088 3809 : else if (strcmp(def->defname, "extensions") == 0)
7089 930 : fpinfo->shippable_extensions =
7090 930 : ExtractExtensionList(defGetString(def), false);
7091 2879 : else if (strcmp(def->defname, "fetch_size") == 0)
7092 0 : (void) parse_int(defGetString(def), &fpinfo->fetch_size, 0, NULL);
7093 2879 : else if (strcmp(def->defname, "async_capable") == 0)
7094 121 : fpinfo->async_capable = defGetBoolean(def);
7095 : }
7096 1216 : }
7097 :
7098 : /*
7099 : * Parse options from foreign table and apply them to fpinfo.
7100 : *
7101 : * New options might also require tweaking merge_fdw_options().
7102 : */
7103 : static void
7104 1216 : apply_table_options(PgFdwRelationInfo *fpinfo)
7105 : {
7106 : ListCell *lc;
7107 :
7108 3522 : foreach(lc, fpinfo->table->options)
7109 : {
7110 2306 : DefElem *def = (DefElem *) lfirst(lc);
7111 :
7112 2306 : if (strcmp(def->defname, "use_remote_estimate") == 0)
7113 348 : fpinfo->use_remote_estimate = defGetBoolean(def);
7114 1958 : else if (strcmp(def->defname, "fetch_size") == 0)
7115 0 : (void) parse_int(defGetString(def), &fpinfo->fetch_size, 0, NULL);
7116 1958 : else if (strcmp(def->defname, "async_capable") == 0)
7117 0 : fpinfo->async_capable = defGetBoolean(def);
7118 : }
7119 1216 : }
7120 :
7121 : /*
7122 : * Merge FDW options from input relations into a new set of options for a join
7123 : * or an upper rel.
7124 : *
7125 : * For a join relation, FDW-specific information about the inner and outer
7126 : * relations is provided using fpinfo_i and fpinfo_o. For an upper relation,
7127 : * fpinfo_o provides the information for the input relation; fpinfo_i is
7128 : * expected to NULL.
7129 : */
7130 : static void
7131 799 : merge_fdw_options(PgFdwRelationInfo *fpinfo,
7132 : const PgFdwRelationInfo *fpinfo_o,
7133 : const PgFdwRelationInfo *fpinfo_i)
7134 : {
7135 : /* We must always have fpinfo_o. */
7136 : Assert(fpinfo_o);
7137 :
7138 : /* fpinfo_i may be NULL, but if present the servers must both match. */
7139 : Assert(!fpinfo_i ||
7140 : fpinfo_i->server->serverid == fpinfo_o->server->serverid);
7141 :
7142 : /*
7143 : * Copy the server specific FDW options. (For a join, both relations come
7144 : * from the same server, so the server options should have the same value
7145 : * for both relations.)
7146 : */
7147 799 : fpinfo->fdw_startup_cost = fpinfo_o->fdw_startup_cost;
7148 799 : fpinfo->fdw_tuple_cost = fpinfo_o->fdw_tuple_cost;
7149 799 : fpinfo->shippable_extensions = fpinfo_o->shippable_extensions;
7150 799 : fpinfo->use_remote_estimate = fpinfo_o->use_remote_estimate;
7151 799 : fpinfo->fetch_size = fpinfo_o->fetch_size;
7152 799 : fpinfo->async_capable = fpinfo_o->async_capable;
7153 :
7154 : /* Merge the table level options from either side of the join. */
7155 799 : if (fpinfo_i)
7156 : {
7157 : /*
7158 : * We'll prefer to use remote estimates for this join if any table
7159 : * from either side of the join is using remote estimates. This is
7160 : * most likely going to be preferred since they're already willing to
7161 : * pay the price of a round trip to get the remote EXPLAIN. In any
7162 : * case it's not entirely clear how we might otherwise handle this
7163 : * best.
7164 : */
7165 532 : fpinfo->use_remote_estimate = fpinfo_o->use_remote_estimate ||
7166 184 : fpinfo_i->use_remote_estimate;
7167 :
7168 : /*
7169 : * Set fetch size to maximum of the joining sides, since we are
7170 : * expecting the rows returned by the join to be proportional to the
7171 : * relation sizes.
7172 : */
7173 348 : fpinfo->fetch_size = Max(fpinfo_o->fetch_size, fpinfo_i->fetch_size);
7174 :
7175 : /*
7176 : * We'll prefer to consider this join async-capable if any table from
7177 : * either side of the join is considered async-capable. This would be
7178 : * reasonable because in that case the foreign server would have its
7179 : * own resources to scan that table asynchronously, and the join could
7180 : * also be computed asynchronously using the resources.
7181 : */
7182 688 : fpinfo->async_capable = fpinfo_o->async_capable ||
7183 688 : fpinfo_i->async_capable;
7184 : }
7185 799 : }
7186 :
7187 : /*
7188 : * postgresGetForeignJoinPaths
7189 : * Add possible ForeignPath to joinrel, if join is safe to push down.
7190 : */
7191 : static void
7192 1360 : postgresGetForeignJoinPaths(PlannerInfo *root,
7193 : RelOptInfo *joinrel,
7194 : RelOptInfo *outerrel,
7195 : RelOptInfo *innerrel,
7196 : JoinType jointype,
7197 : JoinPathExtraData *extra)
7198 : {
7199 : PgFdwRelationInfo *fpinfo;
7200 : ForeignPath *joinpath;
7201 : double rows;
7202 : int width;
7203 : int disabled_nodes;
7204 : Cost startup_cost;
7205 : Cost total_cost;
7206 : Path *epq_path; /* Path to create plan to be executed when
7207 : * EvalPlanQual gets triggered. */
7208 :
7209 : /*
7210 : * Skip if this join combination has been considered already.
7211 : */
7212 1360 : if (joinrel->fdw_private)
7213 1023 : return;
7214 :
7215 : /*
7216 : * This code does not work for joins with lateral references, since those
7217 : * must have parameterized paths, which we don't generate yet.
7218 : */
7219 400 : if (!bms_is_empty(joinrel->lateral_relids))
7220 4 : return;
7221 :
7222 : /*
7223 : * Create unfinished PgFdwRelationInfo entry which is used to indicate
7224 : * that the join relation is already considered, so that we won't waste
7225 : * time in judging safety of join pushdown and adding the same paths again
7226 : * if found safe. Once we know that this join can be pushed down, we fill
7227 : * the entry.
7228 : */
7229 396 : fpinfo = palloc0_object(PgFdwRelationInfo);
7230 396 : fpinfo->pushdown_safe = false;
7231 396 : joinrel->fdw_private = fpinfo;
7232 : /* attrs_used is only for base relations. */
7233 396 : fpinfo->attrs_used = NULL;
7234 :
7235 : /*
7236 : * If there is a possibility that EvalPlanQual will be executed, we need
7237 : * to be able to reconstruct the row using scans of the base relations.
7238 : * GetExistingLocalJoinPath will find a suitable path for this purpose in
7239 : * the path list of the joinrel, if one exists. We must be careful to
7240 : * call it before adding any ForeignPath, since the ForeignPath might
7241 : * dominate the only suitable local path available. We also do it before
7242 : * calling foreign_join_ok(), since that function updates fpinfo and marks
7243 : * it as pushable if the join is found to be pushable.
7244 : */
7245 396 : if (root->parse->commandType == CMD_DELETE ||
7246 382 : root->parse->commandType == CMD_UPDATE ||
7247 356 : root->rowMarks)
7248 : {
7249 78 : epq_path = GetExistingLocalJoinPath(joinrel);
7250 78 : if (!epq_path)
7251 : {
7252 0 : elog(DEBUG3, "could not push down foreign join because a local path suitable for EPQ checks was not found");
7253 0 : return;
7254 : }
7255 : }
7256 : else
7257 318 : epq_path = NULL;
7258 :
7259 396 : if (!foreign_join_ok(root, joinrel, jointype, outerrel, innerrel, extra))
7260 : {
7261 : /* Free path required for EPQ if we copied one; we don't need it now */
7262 59 : if (epq_path)
7263 2 : pfree(epq_path);
7264 59 : return;
7265 : }
7266 :
7267 : /*
7268 : * Compute the selectivity and cost of the local_conds, so we don't have
7269 : * to do it over again for each path. The best we can do for these
7270 : * conditions is to estimate selectivity on the basis of local statistics.
7271 : * The local conditions are applied after the join has been computed on
7272 : * the remote side like quals in WHERE clause, so pass jointype as
7273 : * JOIN_INNER.
7274 : */
7275 337 : fpinfo->local_conds_sel = clauselist_selectivity(root,
7276 : fpinfo->local_conds,
7277 : 0,
7278 : JOIN_INNER,
7279 : NULL);
7280 337 : cost_qual_eval(&fpinfo->local_conds_cost, fpinfo->local_conds, root);
7281 :
7282 : /*
7283 : * If we are going to estimate costs locally, estimate the join clause
7284 : * selectivity here while we have special join info.
7285 : */
7286 337 : if (!fpinfo->use_remote_estimate)
7287 112 : fpinfo->joinclause_sel = clauselist_selectivity(root, fpinfo->joinclauses,
7288 : 0, fpinfo->jointype,
7289 : extra->sjinfo);
7290 :
7291 : /* Estimate costs for bare join relation */
7292 337 : estimate_path_cost_size(root, joinrel, NIL, NIL, NULL,
7293 : &rows, &width, &disabled_nodes,
7294 : &startup_cost, &total_cost);
7295 : /* Now update this information in the joinrel */
7296 337 : joinrel->rows = rows;
7297 337 : joinrel->reltarget->width = width;
7298 337 : fpinfo->rows = rows;
7299 337 : fpinfo->width = width;
7300 337 : fpinfo->disabled_nodes = disabled_nodes;
7301 337 : fpinfo->startup_cost = startup_cost;
7302 337 : fpinfo->total_cost = total_cost;
7303 :
7304 : /*
7305 : * Create a new join path and add it to the joinrel which represents a
7306 : * join between foreign tables.
7307 : */
7308 337 : joinpath = create_foreign_join_path(root,
7309 : joinrel,
7310 : NULL, /* default pathtarget */
7311 : rows,
7312 : disabled_nodes,
7313 : startup_cost,
7314 : total_cost,
7315 : NIL, /* no pathkeys */
7316 : joinrel->lateral_relids,
7317 : epq_path,
7318 : extra->restrictlist,
7319 : NIL); /* no fdw_private */
7320 :
7321 : /* Add generated path into joinrel by add_path(). */
7322 337 : add_path(joinrel, (Path *) joinpath);
7323 :
7324 : /* Consider pathkeys for the join relation */
7325 337 : add_paths_with_pathkeys_for_rel(root, joinrel, epq_path,
7326 : extra->restrictlist);
7327 :
7328 : /* XXX Consider parameterized paths for the join relation */
7329 : }
7330 :
7331 : /*
7332 : * Assess whether the aggregation, grouping and having operations can be pushed
7333 : * down to the foreign server. As a side effect, save information we obtain in
7334 : * this function to PgFdwRelationInfo of the input relation.
7335 : */
7336 : static bool
7337 162 : foreign_grouping_ok(PlannerInfo *root, RelOptInfo *grouped_rel,
7338 : Node *havingQual)
7339 : {
7340 162 : Query *query = root->parse;
7341 162 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) grouped_rel->fdw_private;
7342 162 : PathTarget *grouping_target = grouped_rel->reltarget;
7343 : PgFdwRelationInfo *ofpinfo;
7344 : ListCell *lc;
7345 : int i;
7346 162 : List *tlist = NIL;
7347 :
7348 : /* We currently don't support pushing Grouping Sets. */
7349 162 : if (query->groupingSets)
7350 6 : return false;
7351 :
7352 : /* Get the fpinfo of the underlying scan relation. */
7353 156 : ofpinfo = (PgFdwRelationInfo *) fpinfo->outerrel->fdw_private;
7354 :
7355 : /*
7356 : * If underlying scan relation has any local conditions, those conditions
7357 : * are required to be applied before performing aggregation. Hence the
7358 : * aggregate cannot be pushed down.
7359 : */
7360 156 : if (ofpinfo->local_conds)
7361 9 : return false;
7362 :
7363 : /*
7364 : * Examine grouping expressions, as well as other expressions we'd need to
7365 : * compute, and check whether they are safe to push down to the foreign
7366 : * server. All GROUP BY expressions will be part of the grouping target
7367 : * and thus there is no need to search for them separately. Add grouping
7368 : * expressions into target list which will be passed to foreign server.
7369 : *
7370 : * A tricky fine point is that we must not put any expression into the
7371 : * target list that is just a foreign param (that is, something that
7372 : * deparse.c would conclude has to be sent to the foreign server). If we
7373 : * do, the expression will also appear in the fdw_exprs list of the plan
7374 : * node, and setrefs.c will get confused and decide that the fdw_exprs
7375 : * entry is actually a reference to the fdw_scan_tlist entry, resulting in
7376 : * a broken plan. Somewhat oddly, it's OK if the expression contains such
7377 : * a node, as long as it's not at top level; then no match is possible.
7378 : */
7379 147 : i = 0;
7380 429 : foreach(lc, grouping_target->exprs)
7381 : {
7382 300 : Expr *expr = (Expr *) lfirst(lc);
7383 300 : Index sgref = get_pathtarget_sortgroupref(grouping_target, i);
7384 : ListCell *l;
7385 :
7386 : /*
7387 : * Check whether this expression is part of GROUP BY clause. Note we
7388 : * check the whole GROUP BY clause not just processed_groupClause,
7389 : * because we will ship all of it, cf. appendGroupByClause.
7390 : */
7391 300 : if (sgref && get_sortgroupref_clause_noerr(sgref, query->groupClause))
7392 92 : {
7393 : TargetEntry *tle;
7394 :
7395 : /*
7396 : * If any GROUP BY expression is not shippable, then we cannot
7397 : * push down aggregation to the foreign server.
7398 : */
7399 95 : if (!is_foreign_expr(root, grouped_rel, expr))
7400 18 : return false;
7401 :
7402 : /*
7403 : * If it would be a foreign param, we can't put it into the tlist,
7404 : * so we have to fail.
7405 : */
7406 94 : if (is_foreign_param(root, grouped_rel, expr))
7407 2 : return false;
7408 :
7409 : /*
7410 : * Pushable, so add to tlist. We need to create a TLE for this
7411 : * expression and apply the sortgroupref to it. We cannot use
7412 : * add_to_flat_tlist() here because that avoids making duplicate
7413 : * entries in the tlist. If there are duplicate entries with
7414 : * distinct sortgrouprefs, we have to duplicate that situation in
7415 : * the output tlist.
7416 : */
7417 92 : tle = makeTargetEntry(expr, list_length(tlist) + 1, NULL, false);
7418 92 : tle->ressortgroupref = sgref;
7419 92 : tlist = lappend(tlist, tle);
7420 : }
7421 : else
7422 : {
7423 : /*
7424 : * Non-grouping expression we need to compute. Can we ship it
7425 : * as-is to the foreign server?
7426 : */
7427 205 : if (is_foreign_expr(root, grouped_rel, expr) &&
7428 184 : !is_foreign_param(root, grouped_rel, expr))
7429 : {
7430 : /* Yes, so add to tlist as-is; OK to suppress duplicates */
7431 182 : tlist = add_to_flat_tlist(tlist, list_make1(expr));
7432 : }
7433 : else
7434 : {
7435 : /* Not pushable as a whole; extract its Vars and aggregates */
7436 : List *aggvars;
7437 :
7438 23 : aggvars = pull_var_clause((Node *) expr,
7439 : PVC_INCLUDE_AGGREGATES);
7440 :
7441 : /*
7442 : * If any aggregate expression is not shippable, then we
7443 : * cannot push down aggregation to the foreign server. (We
7444 : * don't have to check is_foreign_param, since that certainly
7445 : * won't return true for any such expression.)
7446 : */
7447 23 : if (!is_foreign_expr(root, grouped_rel, (Expr *) aggvars))
7448 15 : return false;
7449 :
7450 : /*
7451 : * Add aggregates, if any, into the targetlist. Plain Vars
7452 : * outside an aggregate can be ignored, because they should be
7453 : * either same as some GROUP BY column or part of some GROUP
7454 : * BY expression. In either case, they are already part of
7455 : * the targetlist and thus no need to add them again. In fact
7456 : * including plain Vars in the tlist when they do not match a
7457 : * GROUP BY column would cause the foreign server to complain
7458 : * that the shipped query is invalid.
7459 : */
7460 14 : foreach(l, aggvars)
7461 : {
7462 6 : Expr *aggref = (Expr *) lfirst(l);
7463 :
7464 6 : if (IsA(aggref, Aggref))
7465 4 : tlist = add_to_flat_tlist(tlist, list_make1(aggref));
7466 : }
7467 : }
7468 : }
7469 :
7470 282 : i++;
7471 : }
7472 :
7473 : /*
7474 : * Classify the pushable and non-pushable HAVING clauses and save them in
7475 : * remote_conds and local_conds of the grouped rel's fpinfo.
7476 : */
7477 129 : if (havingQual)
7478 : {
7479 34 : foreach(lc, (List *) havingQual)
7480 : {
7481 19 : Expr *expr = (Expr *) lfirst(lc);
7482 : RestrictInfo *rinfo;
7483 :
7484 : /*
7485 : * Currently, the core code doesn't wrap havingQuals in
7486 : * RestrictInfos, so we must make our own.
7487 : */
7488 : Assert(!IsA(expr, RestrictInfo));
7489 19 : rinfo = make_restrictinfo(root,
7490 : expr,
7491 : true,
7492 : false,
7493 : false,
7494 : false,
7495 : root->qual_security_level,
7496 : grouped_rel->relids,
7497 : NULL,
7498 : NULL);
7499 19 : if (is_foreign_expr(root, grouped_rel, expr))
7500 16 : fpinfo->remote_conds = lappend(fpinfo->remote_conds, rinfo);
7501 : else
7502 3 : fpinfo->local_conds = lappend(fpinfo->local_conds, rinfo);
7503 : }
7504 : }
7505 :
7506 : /*
7507 : * If there are any local conditions, pull Vars and aggregates from it and
7508 : * check whether they are safe to pushdown or not.
7509 : */
7510 129 : if (fpinfo->local_conds)
7511 : {
7512 3 : List *aggvars = NIL;
7513 :
7514 6 : foreach(lc, fpinfo->local_conds)
7515 : {
7516 3 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
7517 :
7518 3 : aggvars = list_concat(aggvars,
7519 3 : pull_var_clause((Node *) rinfo->clause,
7520 : PVC_INCLUDE_AGGREGATES));
7521 : }
7522 :
7523 7 : foreach(lc, aggvars)
7524 : {
7525 5 : Expr *expr = (Expr *) lfirst(lc);
7526 :
7527 : /*
7528 : * If aggregates within local conditions are not safe to push
7529 : * down, then we cannot push down the query. Vars are already
7530 : * part of GROUP BY clause which are checked above, so no need to
7531 : * access them again here. Again, we need not check
7532 : * is_foreign_param for a foreign aggregate.
7533 : */
7534 5 : if (IsA(expr, Aggref))
7535 : {
7536 5 : if (!is_foreign_expr(root, grouped_rel, expr))
7537 1 : return false;
7538 :
7539 4 : tlist = add_to_flat_tlist(tlist, list_make1(expr));
7540 : }
7541 : }
7542 : }
7543 :
7544 : /* Store generated targetlist */
7545 128 : fpinfo->grouped_tlist = tlist;
7546 :
7547 : /* Safe to pushdown */
7548 128 : fpinfo->pushdown_safe = true;
7549 :
7550 : /*
7551 : * Set # of retrieved rows and cached relation costs to some negative
7552 : * value, so that we can detect when they are set to some sensible values,
7553 : * during one (usually the first) of the calls to estimate_path_cost_size.
7554 : */
7555 128 : fpinfo->retrieved_rows = -1;
7556 128 : fpinfo->rel_startup_cost = -1;
7557 128 : fpinfo->rel_total_cost = -1;
7558 :
7559 : /*
7560 : * Set the string describing this grouped relation to be used in EXPLAIN
7561 : * output of corresponding ForeignScan. Note that the decoration we add
7562 : * to the base relation name mustn't include any digits, or it'll confuse
7563 : * postgresExplainForeignScan.
7564 : */
7565 128 : fpinfo->relation_name = psprintf("Aggregate on (%s)",
7566 : ofpinfo->relation_name);
7567 :
7568 128 : return true;
7569 : }
7570 :
7571 : /*
7572 : * postgresGetForeignUpperPaths
7573 : * Add paths for post-join operations like aggregation, grouping etc. if
7574 : * corresponding operations are safe to push down.
7575 : */
7576 : static void
7577 995 : postgresGetForeignUpperPaths(PlannerInfo *root, UpperRelationKind stage,
7578 : RelOptInfo *input_rel, RelOptInfo *output_rel,
7579 : void *extra)
7580 : {
7581 : PgFdwRelationInfo *fpinfo;
7582 :
7583 : /*
7584 : * If input rel is not safe to pushdown, then simply return as we cannot
7585 : * perform any post-join operations on the foreign server.
7586 : */
7587 995 : if (!input_rel->fdw_private ||
7588 929 : !((PgFdwRelationInfo *) input_rel->fdw_private)->pushdown_safe)
7589 122 : return;
7590 :
7591 : /* Ignore stages we don't support; and skip any duplicate calls. */
7592 873 : if ((stage != UPPERREL_GROUP_AGG &&
7593 557 : stage != UPPERREL_ORDERED &&
7594 856 : stage != UPPERREL_FINAL) ||
7595 856 : output_rel->fdw_private)
7596 17 : return;
7597 :
7598 856 : fpinfo = palloc0_object(PgFdwRelationInfo);
7599 856 : fpinfo->pushdown_safe = false;
7600 856 : fpinfo->stage = stage;
7601 856 : output_rel->fdw_private = fpinfo;
7602 :
7603 856 : switch (stage)
7604 : {
7605 162 : case UPPERREL_GROUP_AGG:
7606 162 : add_foreign_grouping_paths(root, input_rel, output_rel,
7607 : (GroupPathExtraData *) extra);
7608 162 : break;
7609 154 : case UPPERREL_ORDERED:
7610 154 : add_foreign_ordered_paths(root, input_rel, output_rel);
7611 154 : break;
7612 540 : case UPPERREL_FINAL:
7613 540 : add_foreign_final_paths(root, input_rel, output_rel,
7614 : (FinalPathExtraData *) extra);
7615 540 : break;
7616 0 : default:
7617 0 : elog(ERROR, "unexpected upper relation: %d", (int) stage);
7618 : break;
7619 : }
7620 : }
7621 :
7622 : /*
7623 : * add_foreign_grouping_paths
7624 : * Add foreign path for grouping and/or aggregation.
7625 : *
7626 : * Given input_rel represents the underlying scan. The paths are added to the
7627 : * given grouped_rel.
7628 : */
7629 : static void
7630 162 : add_foreign_grouping_paths(PlannerInfo *root, RelOptInfo *input_rel,
7631 : RelOptInfo *grouped_rel,
7632 : GroupPathExtraData *extra)
7633 : {
7634 162 : Query *parse = root->parse;
7635 162 : PgFdwRelationInfo *ifpinfo = input_rel->fdw_private;
7636 162 : PgFdwRelationInfo *fpinfo = grouped_rel->fdw_private;
7637 : ForeignPath *grouppath;
7638 : double rows;
7639 : int width;
7640 : int disabled_nodes;
7641 : Cost startup_cost;
7642 : Cost total_cost;
7643 :
7644 : /* Nothing to be done, if there is no grouping or aggregation required. */
7645 162 : if (!parse->groupClause && !parse->groupingSets && !parse->hasAggs &&
7646 0 : !root->hasHavingQual)
7647 34 : return;
7648 :
7649 : Assert(extra->patype == PARTITIONWISE_AGGREGATE_NONE ||
7650 : extra->patype == PARTITIONWISE_AGGREGATE_FULL);
7651 :
7652 : /* save the input_rel as outerrel in fpinfo */
7653 162 : fpinfo->outerrel = input_rel;
7654 :
7655 : /*
7656 : * Copy foreign table, foreign server, user mapping, FDW options etc.
7657 : * details from the input relation's fpinfo.
7658 : */
7659 162 : fpinfo->table = ifpinfo->table;
7660 162 : fpinfo->server = ifpinfo->server;
7661 162 : fpinfo->user = ifpinfo->user;
7662 162 : merge_fdw_options(fpinfo, ifpinfo, NULL);
7663 :
7664 : /*
7665 : * Assess if it is safe to push down aggregation and grouping.
7666 : *
7667 : * Use HAVING qual from extra. In case of child partition, it will have
7668 : * translated Vars.
7669 : */
7670 162 : if (!foreign_grouping_ok(root, grouped_rel, extra->havingQual))
7671 34 : return;
7672 :
7673 : /*
7674 : * Compute the selectivity and cost of the local_conds, so we don't have
7675 : * to do it over again for each path. (Currently we create just a single
7676 : * path here, but in future it would be possible that we build more paths
7677 : * such as pre-sorted paths as in postgresGetForeignPaths and
7678 : * postgresGetForeignJoinPaths.) The best we can do for these conditions
7679 : * is to estimate selectivity on the basis of local statistics.
7680 : */
7681 128 : fpinfo->local_conds_sel = clauselist_selectivity(root,
7682 : fpinfo->local_conds,
7683 : 0,
7684 : JOIN_INNER,
7685 : NULL);
7686 :
7687 128 : cost_qual_eval(&fpinfo->local_conds_cost, fpinfo->local_conds, root);
7688 :
7689 : /* Estimate the cost of push down */
7690 128 : estimate_path_cost_size(root, grouped_rel, NIL, NIL, NULL,
7691 : &rows, &width, &disabled_nodes,
7692 : &startup_cost, &total_cost);
7693 :
7694 : /* Now update this information in the fpinfo */
7695 128 : fpinfo->rows = rows;
7696 128 : fpinfo->width = width;
7697 128 : fpinfo->disabled_nodes = disabled_nodes;
7698 128 : fpinfo->startup_cost = startup_cost;
7699 128 : fpinfo->total_cost = total_cost;
7700 :
7701 : /* Create and add foreign path to the grouping relation. */
7702 128 : grouppath = create_foreign_upper_path(root,
7703 : grouped_rel,
7704 128 : grouped_rel->reltarget,
7705 : rows,
7706 : disabled_nodes,
7707 : startup_cost,
7708 : total_cost,
7709 : NIL, /* no pathkeys */
7710 : NULL,
7711 : NIL, /* no fdw_restrictinfo list */
7712 : NIL); /* no fdw_private */
7713 :
7714 : /* Add generated path into grouped_rel by add_path(). */
7715 128 : add_path(grouped_rel, (Path *) grouppath);
7716 : }
7717 :
7718 : /*
7719 : * add_foreign_ordered_paths
7720 : * Add foreign paths for performing the final sort remotely.
7721 : *
7722 : * Given input_rel contains the source-data Paths. The paths are added to the
7723 : * given ordered_rel.
7724 : */
7725 : static void
7726 154 : add_foreign_ordered_paths(PlannerInfo *root, RelOptInfo *input_rel,
7727 : RelOptInfo *ordered_rel)
7728 : {
7729 154 : Query *parse = root->parse;
7730 154 : PgFdwRelationInfo *ifpinfo = input_rel->fdw_private;
7731 154 : PgFdwRelationInfo *fpinfo = ordered_rel->fdw_private;
7732 : PgFdwPathExtraData *fpextra;
7733 : double rows;
7734 : int width;
7735 : int disabled_nodes;
7736 : Cost startup_cost;
7737 : Cost total_cost;
7738 : List *fdw_private;
7739 : ForeignPath *ordered_path;
7740 : ListCell *lc;
7741 :
7742 : /* Shouldn't get here unless the query has ORDER BY */
7743 : Assert(parse->sortClause);
7744 :
7745 : /* We don't support cases where there are any SRFs in the targetlist */
7746 154 : if (parse->hasTargetSRFs)
7747 112 : return;
7748 :
7749 : /* Save the input_rel as outerrel in fpinfo */
7750 154 : fpinfo->outerrel = input_rel;
7751 :
7752 : /*
7753 : * Copy foreign table, foreign server, user mapping, FDW options etc.
7754 : * details from the input relation's fpinfo.
7755 : */
7756 154 : fpinfo->table = ifpinfo->table;
7757 154 : fpinfo->server = ifpinfo->server;
7758 154 : fpinfo->user = ifpinfo->user;
7759 154 : merge_fdw_options(fpinfo, ifpinfo, NULL);
7760 :
7761 : /*
7762 : * If the input_rel is a base or join relation, we would already have
7763 : * considered pushing down the final sort to the remote server when
7764 : * creating pre-sorted foreign paths for that relation, because the
7765 : * query_pathkeys is set to the root->sort_pathkeys in that case (see
7766 : * standard_qp_callback()).
7767 : */
7768 154 : if (input_rel->reloptkind == RELOPT_BASEREL ||
7769 109 : input_rel->reloptkind == RELOPT_JOINREL)
7770 : {
7771 : Assert(root->query_pathkeys == root->sort_pathkeys);
7772 :
7773 : /* Safe to push down if the query_pathkeys is safe to push down */
7774 108 : fpinfo->pushdown_safe = ifpinfo->qp_is_pushdown_safe;
7775 :
7776 108 : return;
7777 : }
7778 :
7779 : /* The input_rel should be a grouping relation */
7780 : Assert(input_rel->reloptkind == RELOPT_UPPER_REL &&
7781 : ifpinfo->stage == UPPERREL_GROUP_AGG);
7782 :
7783 : /*
7784 : * We try to create a path below by extending a simple foreign path for
7785 : * the underlying grouping relation to perform the final sort remotely,
7786 : * which is stored into the fdw_private list of the resulting path.
7787 : */
7788 :
7789 : /* Assess if it is safe to push down the final sort */
7790 94 : foreach(lc, root->sort_pathkeys)
7791 : {
7792 52 : PathKey *pathkey = (PathKey *) lfirst(lc);
7793 52 : EquivalenceClass *pathkey_ec = pathkey->pk_eclass;
7794 :
7795 : /*
7796 : * is_foreign_expr would detect volatile expressions as well, but
7797 : * checking ec_has_volatile here saves some cycles.
7798 : */
7799 52 : if (pathkey_ec->ec_has_volatile)
7800 4 : return;
7801 :
7802 : /*
7803 : * Can't push down the sort if pathkey's opfamily is not shippable.
7804 : */
7805 48 : if (!is_shippable(pathkey->pk_opfamily, OperatorFamilyRelationId,
7806 : fpinfo))
7807 0 : return;
7808 :
7809 : /*
7810 : * The EC must contain a shippable EM that is computed in input_rel's
7811 : * reltarget, else we can't push down the sort.
7812 : */
7813 48 : if (find_em_for_rel_target(root,
7814 : pathkey_ec,
7815 : input_rel) == NULL)
7816 0 : return;
7817 : }
7818 :
7819 : /* Safe to push down */
7820 42 : fpinfo->pushdown_safe = true;
7821 :
7822 : /* Construct PgFdwPathExtraData */
7823 42 : fpextra = palloc0_object(PgFdwPathExtraData);
7824 42 : fpextra->target = root->upper_targets[UPPERREL_ORDERED];
7825 42 : fpextra->has_final_sort = true;
7826 :
7827 : /* Estimate the costs of performing the final sort remotely */
7828 42 : estimate_path_cost_size(root, input_rel, NIL, root->sort_pathkeys, fpextra,
7829 : &rows, &width, &disabled_nodes,
7830 : &startup_cost, &total_cost);
7831 :
7832 : /*
7833 : * Build the fdw_private list that will be used by postgresGetForeignPlan.
7834 : * Items in the list must match order in enum FdwPathPrivateIndex.
7835 : */
7836 42 : fdw_private = list_make2(makeBoolean(true), makeBoolean(false));
7837 :
7838 : /* Create foreign ordering path */
7839 42 : ordered_path = create_foreign_upper_path(root,
7840 : input_rel,
7841 42 : root->upper_targets[UPPERREL_ORDERED],
7842 : rows,
7843 : disabled_nodes,
7844 : startup_cost,
7845 : total_cost,
7846 : root->sort_pathkeys,
7847 : NULL, /* no extra plan */
7848 : NIL, /* no fdw_restrictinfo
7849 : * list */
7850 : fdw_private);
7851 :
7852 : /* and add it to the ordered_rel */
7853 42 : add_path(ordered_rel, (Path *) ordered_path);
7854 : }
7855 :
7856 : /*
7857 : * add_foreign_final_paths
7858 : * Add foreign paths for performing the final processing remotely.
7859 : *
7860 : * Given input_rel contains the source-data Paths. The paths are added to the
7861 : * given final_rel.
7862 : */
7863 : static void
7864 540 : add_foreign_final_paths(PlannerInfo *root, RelOptInfo *input_rel,
7865 : RelOptInfo *final_rel,
7866 : FinalPathExtraData *extra)
7867 : {
7868 540 : Query *parse = root->parse;
7869 540 : PgFdwRelationInfo *ifpinfo = (PgFdwRelationInfo *) input_rel->fdw_private;
7870 540 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) final_rel->fdw_private;
7871 540 : bool has_final_sort = false;
7872 540 : List *pathkeys = NIL;
7873 : PgFdwPathExtraData *fpextra;
7874 540 : bool save_use_remote_estimate = false;
7875 : double rows;
7876 : int width;
7877 : int disabled_nodes;
7878 : Cost startup_cost;
7879 : Cost total_cost;
7880 : List *fdw_private;
7881 : ForeignPath *final_path;
7882 :
7883 : /*
7884 : * Currently, we only support this for SELECT commands
7885 : */
7886 540 : if (parse->commandType != CMD_SELECT)
7887 419 : return;
7888 :
7889 : /*
7890 : * No work if there is no FOR UPDATE/SHARE clause and if there is no need
7891 : * to add a LIMIT node
7892 : */
7893 427 : if (!parse->rowMarks && !extra->limit_needed)
7894 292 : return;
7895 :
7896 : /* We don't support cases where there are any SRFs in the targetlist */
7897 135 : if (parse->hasTargetSRFs)
7898 0 : return;
7899 :
7900 : /* Save the input_rel as outerrel in fpinfo */
7901 135 : fpinfo->outerrel = input_rel;
7902 :
7903 : /*
7904 : * Copy foreign table, foreign server, user mapping, FDW options etc.
7905 : * details from the input relation's fpinfo.
7906 : */
7907 135 : fpinfo->table = ifpinfo->table;
7908 135 : fpinfo->server = ifpinfo->server;
7909 135 : fpinfo->user = ifpinfo->user;
7910 135 : merge_fdw_options(fpinfo, ifpinfo, NULL);
7911 :
7912 : /*
7913 : * If there is no need to add a LIMIT node, there might be a ForeignPath
7914 : * in the input_rel's pathlist that implements all behavior of the query.
7915 : * Note: we would already have accounted for the query's FOR UPDATE/SHARE
7916 : * (if any) before we get here.
7917 : */
7918 135 : if (!extra->limit_needed)
7919 : {
7920 : ListCell *lc;
7921 :
7922 : Assert(parse->rowMarks);
7923 :
7924 : /*
7925 : * Grouping and aggregation are not supported with FOR UPDATE/SHARE,
7926 : * so the input_rel should be a base, join, or ordered relation; and
7927 : * if it's an ordered relation, its input relation should be a base or
7928 : * join relation.
7929 : */
7930 : Assert(input_rel->reloptkind == RELOPT_BASEREL ||
7931 : input_rel->reloptkind == RELOPT_JOINREL ||
7932 : (input_rel->reloptkind == RELOPT_UPPER_REL &&
7933 : ifpinfo->stage == UPPERREL_ORDERED &&
7934 : (ifpinfo->outerrel->reloptkind == RELOPT_BASEREL ||
7935 : ifpinfo->outerrel->reloptkind == RELOPT_JOINREL)));
7936 :
7937 4 : foreach(lc, input_rel->pathlist)
7938 : {
7939 4 : Path *path = (Path *) lfirst(lc);
7940 :
7941 : /*
7942 : * apply_scanjoin_target_to_paths() uses create_projection_path()
7943 : * to adjust each of its input paths if needed, whereas
7944 : * create_ordered_paths() uses apply_projection_to_path() to do
7945 : * that. So the former might have put a ProjectionPath on top of
7946 : * the ForeignPath; look through ProjectionPath and see if the
7947 : * path underneath it is ForeignPath.
7948 : */
7949 4 : if (IsA(path, ForeignPath) ||
7950 0 : (IsA(path, ProjectionPath) &&
7951 0 : IsA(((ProjectionPath *) path)->subpath, ForeignPath)))
7952 : {
7953 : /*
7954 : * Create foreign final path; this gets rid of a
7955 : * no-longer-needed outer plan (if any), which makes the
7956 : * EXPLAIN output look cleaner
7957 : */
7958 4 : final_path = create_foreign_upper_path(root,
7959 : path->parent,
7960 : path->pathtarget,
7961 : path->rows,
7962 : path->disabled_nodes,
7963 : path->startup_cost,
7964 : path->total_cost,
7965 : path->pathkeys,
7966 : NULL, /* no extra plan */
7967 : NIL, /* no fdw_restrictinfo
7968 : * list */
7969 : NIL); /* no fdw_private */
7970 :
7971 : /* and add it to the final_rel */
7972 4 : add_path(final_rel, (Path *) final_path);
7973 :
7974 : /* Safe to push down */
7975 4 : fpinfo->pushdown_safe = true;
7976 :
7977 4 : return;
7978 : }
7979 : }
7980 :
7981 : /*
7982 : * If we get here it means no ForeignPaths; since we would already
7983 : * have considered pushing down all operations for the query to the
7984 : * remote server, give up on it.
7985 : */
7986 0 : return;
7987 : }
7988 :
7989 : Assert(extra->limit_needed);
7990 :
7991 : /*
7992 : * If the input_rel is an ordered relation, replace the input_rel with its
7993 : * input relation
7994 : */
7995 131 : if (input_rel->reloptkind == RELOPT_UPPER_REL &&
7996 74 : ifpinfo->stage == UPPERREL_ORDERED)
7997 : {
7998 74 : input_rel = ifpinfo->outerrel;
7999 74 : ifpinfo = (PgFdwRelationInfo *) input_rel->fdw_private;
8000 74 : has_final_sort = true;
8001 74 : pathkeys = root->sort_pathkeys;
8002 : }
8003 :
8004 : /* The input_rel should be a base, join, or grouping relation */
8005 : Assert(input_rel->reloptkind == RELOPT_BASEREL ||
8006 : input_rel->reloptkind == RELOPT_JOINREL ||
8007 : (input_rel->reloptkind == RELOPT_UPPER_REL &&
8008 : ifpinfo->stage == UPPERREL_GROUP_AGG));
8009 :
8010 : /*
8011 : * We try to create a path below by extending a simple foreign path for
8012 : * the underlying base, join, or grouping relation to perform the final
8013 : * sort (if has_final_sort) and the LIMIT restriction remotely, which is
8014 : * stored into the fdw_private list of the resulting path. (We
8015 : * re-estimate the costs of sorting the underlying relation, if
8016 : * has_final_sort.)
8017 : */
8018 :
8019 : /*
8020 : * Assess if it is safe to push down the LIMIT and OFFSET to the remote
8021 : * server
8022 : */
8023 :
8024 : /*
8025 : * If the underlying relation has any local conditions, the LIMIT/OFFSET
8026 : * cannot be pushed down.
8027 : */
8028 131 : if (ifpinfo->local_conds)
8029 8 : return;
8030 :
8031 : /*
8032 : * If the query has FETCH FIRST .. WITH TIES, 1) it must have ORDER BY as
8033 : * well, which is used to determine which additional rows tie for the last
8034 : * place in the result set, and 2) ORDER BY must already have been
8035 : * determined to be safe to push down before we get here. So in that case
8036 : * the FETCH clause is safe to push down with ORDER BY if the remote
8037 : * server is v13 or later, but if not, the remote query will fail entirely
8038 : * for lack of support for it. Since we do not currently have a way to do
8039 : * a remote-version check (without accessing the remote server), disable
8040 : * pushing the FETCH clause for now.
8041 : */
8042 123 : if (parse->limitOption == LIMIT_OPTION_WITH_TIES)
8043 2 : return;
8044 :
8045 : /*
8046 : * Also, the LIMIT/OFFSET cannot be pushed down, if their expressions are
8047 : * not safe to remote.
8048 : */
8049 121 : if (!is_foreign_expr(root, input_rel, (Expr *) parse->limitOffset) ||
8050 121 : !is_foreign_expr(root, input_rel, (Expr *) parse->limitCount))
8051 0 : return;
8052 :
8053 : /* Safe to push down */
8054 121 : fpinfo->pushdown_safe = true;
8055 :
8056 : /* Construct PgFdwPathExtraData */
8057 121 : fpextra = palloc0_object(PgFdwPathExtraData);
8058 121 : fpextra->target = root->upper_targets[UPPERREL_FINAL];
8059 121 : fpextra->has_final_sort = has_final_sort;
8060 121 : fpextra->has_limit = extra->limit_needed;
8061 121 : fpextra->limit_tuples = extra->limit_tuples;
8062 121 : fpextra->count_est = extra->count_est;
8063 121 : fpextra->offset_est = extra->offset_est;
8064 :
8065 : /*
8066 : * Estimate the costs of performing the final sort and the LIMIT
8067 : * restriction remotely. If has_final_sort is false, we wouldn't need to
8068 : * execute EXPLAIN anymore if use_remote_estimate, since the costs can be
8069 : * roughly estimated using the costs we already have for the underlying
8070 : * relation, in the same way as when use_remote_estimate is false. Since
8071 : * it's pretty expensive to execute EXPLAIN, force use_remote_estimate to
8072 : * false in that case.
8073 : */
8074 121 : if (!fpextra->has_final_sort)
8075 : {
8076 54 : save_use_remote_estimate = ifpinfo->use_remote_estimate;
8077 54 : ifpinfo->use_remote_estimate = false;
8078 : }
8079 121 : estimate_path_cost_size(root, input_rel, NIL, pathkeys, fpextra,
8080 : &rows, &width, &disabled_nodes,
8081 : &startup_cost, &total_cost);
8082 121 : if (!fpextra->has_final_sort)
8083 54 : ifpinfo->use_remote_estimate = save_use_remote_estimate;
8084 :
8085 : /*
8086 : * Build the fdw_private list that will be used by postgresGetForeignPlan.
8087 : * Items in the list must match order in enum FdwPathPrivateIndex.
8088 : */
8089 121 : fdw_private = list_make2(makeBoolean(has_final_sort),
8090 : makeBoolean(extra->limit_needed));
8091 :
8092 : /*
8093 : * Create foreign final path; this gets rid of a no-longer-needed outer
8094 : * plan (if any), which makes the EXPLAIN output look cleaner
8095 : */
8096 121 : final_path = create_foreign_upper_path(root,
8097 : input_rel,
8098 121 : root->upper_targets[UPPERREL_FINAL],
8099 : rows,
8100 : disabled_nodes,
8101 : startup_cost,
8102 : total_cost,
8103 : pathkeys,
8104 : NULL, /* no extra plan */
8105 : NIL, /* no fdw_restrictinfo list */
8106 : fdw_private);
8107 :
8108 : /* and add it to the final_rel */
8109 121 : add_path(final_rel, (Path *) final_path);
8110 : }
8111 :
8112 : /*
8113 : * postgresIsForeignPathAsyncCapable
8114 : * Check whether a given ForeignPath node is async-capable.
8115 : */
8116 : static bool
8117 237 : postgresIsForeignPathAsyncCapable(ForeignPath *path)
8118 : {
8119 237 : RelOptInfo *rel = ((Path *) path)->parent;
8120 237 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private;
8121 :
8122 237 : return fpinfo->async_capable;
8123 : }
8124 :
8125 : /*
8126 : * postgresForeignAsyncRequest
8127 : * Asynchronously request next tuple from a foreign PostgreSQL table.
8128 : */
8129 : static void
8130 6175 : postgresForeignAsyncRequest(AsyncRequest *areq)
8131 : {
8132 6175 : produce_tuple_asynchronously(areq, true);
8133 6175 : }
8134 :
8135 : /*
8136 : * postgresForeignAsyncConfigureWait
8137 : * Configure a file descriptor event for which we wish to wait.
8138 : */
8139 : static void
8140 239 : postgresForeignAsyncConfigureWait(AsyncRequest *areq)
8141 : {
8142 239 : ForeignScanState *node = (ForeignScanState *) areq->requestee;
8143 239 : PgFdwScanState *fsstate = (PgFdwScanState *) node->fdw_state;
8144 239 : AsyncRequest *pendingAreq = fsstate->conn_state->pendingAreq;
8145 239 : AppendState *requestor = (AppendState *) areq->requestor;
8146 239 : WaitEventSet *set = requestor->as_eventset;
8147 :
8148 : /* This should not be called unless callback_pending */
8149 : Assert(areq->callback_pending);
8150 :
8151 : /*
8152 : * If process_pending_request() has been invoked on the given request
8153 : * before we get here, we might have some tuples already; in which case
8154 : * complete the request
8155 : */
8156 239 : if (fsstate->next_tuple < fsstate->num_tuples)
8157 : {
8158 5 : complete_pending_request(areq);
8159 5 : if (areq->request_complete)
8160 3 : return;
8161 : Assert(areq->callback_pending);
8162 : }
8163 :
8164 : /* We must have run out of tuples */
8165 : Assert(fsstate->next_tuple >= fsstate->num_tuples);
8166 :
8167 : /* The core code would have registered postmaster death event */
8168 : Assert(GetNumRegisteredWaitEvents(set) >= 1);
8169 :
8170 : /* Begin an asynchronous data fetch if not already done */
8171 236 : if (!pendingAreq)
8172 4 : fetch_more_data_begin(areq);
8173 232 : else if (pendingAreq->requestor != areq->requestor)
8174 : {
8175 : /*
8176 : * This is the case when the in-process request was made by another
8177 : * Append. Note that it might be useless to process the request made
8178 : * by that Append, because the query might not need tuples from that
8179 : * Append anymore; so we avoid processing it to begin a fetch for the
8180 : * given request if possible. If there are any child subplans of the
8181 : * same parent that are ready for new requests, skip the given
8182 : * request. Likewise, if there are any configured events other than
8183 : * the postmaster death event, skip it. Otherwise, process the
8184 : * in-process request, then begin a fetch to configure the event
8185 : * below, because we might otherwise end up with no configured events
8186 : * other than the postmaster death event.
8187 : */
8188 8 : if (!bms_is_empty(requestor->as_needrequest))
8189 0 : return;
8190 8 : if (GetNumRegisteredWaitEvents(set) > 1)
8191 6 : return;
8192 2 : process_pending_request(pendingAreq);
8193 2 : fetch_more_data_begin(areq);
8194 : }
8195 224 : else if (pendingAreq->requestee != areq->requestee)
8196 : {
8197 : /*
8198 : * This is the case when the in-process request was made by the same
8199 : * parent but for a different child. Since we configure only the
8200 : * event for the request made for that child, skip the given request.
8201 : */
8202 9 : return;
8203 : }
8204 : else
8205 : Assert(pendingAreq == areq);
8206 :
8207 220 : AddWaitEventToSet(set, WL_SOCKET_READABLE, PQsocket(fsstate->conn),
8208 : NULL, areq);
8209 : }
8210 :
8211 : /*
8212 : * postgresForeignAsyncNotify
8213 : * Fetch some more tuples from a file descriptor that becomes ready,
8214 : * requesting next tuple.
8215 : */
8216 : static void
8217 149 : postgresForeignAsyncNotify(AsyncRequest *areq)
8218 : {
8219 149 : ForeignScanState *node = (ForeignScanState *) areq->requestee;
8220 149 : PgFdwScanState *fsstate = (PgFdwScanState *) node->fdw_state;
8221 :
8222 : /* The core code would have initialized the callback_pending flag */
8223 : Assert(!areq->callback_pending);
8224 :
8225 : /*
8226 : * If process_pending_request() has been invoked on the given request
8227 : * before we get here, we might have some tuples already; in which case
8228 : * produce the next tuple
8229 : */
8230 149 : if (fsstate->next_tuple < fsstate->num_tuples)
8231 : {
8232 0 : produce_tuple_asynchronously(areq, true);
8233 0 : return;
8234 : }
8235 :
8236 : /* We must have run out of tuples */
8237 : Assert(fsstate->next_tuple >= fsstate->num_tuples);
8238 :
8239 : /* The request should be currently in-process */
8240 : Assert(fsstate->conn_state->pendingAreq == areq);
8241 :
8242 : /* On error, report the original query, not the FETCH. */
8243 149 : if (!PQconsumeInput(fsstate->conn))
8244 0 : pgfdw_report_error(NULL, fsstate->conn, fsstate->query);
8245 :
8246 149 : fetch_more_data(node);
8247 :
8248 149 : produce_tuple_asynchronously(areq, true);
8249 : }
8250 :
8251 : /*
8252 : * Asynchronously produce next tuple from a foreign PostgreSQL table.
8253 : */
8254 : static void
8255 6329 : produce_tuple_asynchronously(AsyncRequest *areq, bool fetch)
8256 : {
8257 6329 : ForeignScanState *node = (ForeignScanState *) areq->requestee;
8258 6329 : PgFdwScanState *fsstate = (PgFdwScanState *) node->fdw_state;
8259 6329 : AsyncRequest *pendingAreq = fsstate->conn_state->pendingAreq;
8260 : TupleTableSlot *result;
8261 :
8262 : /* This should not be called if the request is currently in-process */
8263 : Assert(areq != pendingAreq);
8264 :
8265 : /* Fetch some more tuples, if we've run out */
8266 6329 : if (fsstate->next_tuple >= fsstate->num_tuples)
8267 : {
8268 : /* No point in another fetch if we already detected EOF, though */
8269 190 : if (!fsstate->eof_reached)
8270 : {
8271 : /* Mark the request as pending for a callback */
8272 129 : ExecAsyncRequestPending(areq);
8273 : /* Begin another fetch if requested and if no pending request */
8274 129 : if (fetch && !pendingAreq)
8275 124 : fetch_more_data_begin(areq);
8276 : }
8277 : else
8278 : {
8279 : /* There's nothing more to do; just return a NULL pointer */
8280 61 : result = NULL;
8281 : /* Mark the request as complete */
8282 61 : ExecAsyncRequestDone(areq, result);
8283 : }
8284 190 : return;
8285 : }
8286 :
8287 : /* Get a tuple from the ForeignScan node */
8288 6139 : result = areq->requestee->ExecProcNodeReal(areq->requestee);
8289 6139 : if (!TupIsNull(result))
8290 : {
8291 : /* Mark the request as complete */
8292 6107 : ExecAsyncRequestDone(areq, result);
8293 6107 : return;
8294 : }
8295 :
8296 : /* We must have run out of tuples */
8297 : Assert(fsstate->next_tuple >= fsstate->num_tuples);
8298 :
8299 : /* Fetch some more tuples, if we've not detected EOF yet */
8300 32 : if (!fsstate->eof_reached)
8301 : {
8302 : /* Mark the request as pending for a callback */
8303 32 : ExecAsyncRequestPending(areq);
8304 : /* Begin another fetch if requested and if no pending request */
8305 32 : if (fetch && !pendingAreq)
8306 30 : fetch_more_data_begin(areq);
8307 : }
8308 : else
8309 : {
8310 : /* There's nothing more to do; just return a NULL pointer */
8311 0 : result = NULL;
8312 : /* Mark the request as complete */
8313 0 : ExecAsyncRequestDone(areq, result);
8314 : }
8315 : }
8316 :
8317 : /*
8318 : * Begin an asynchronous data fetch.
8319 : *
8320 : * Note: this function assumes there is no currently-in-progress asynchronous
8321 : * data fetch.
8322 : *
8323 : * Note: fetch_more_data must be called to fetch the result.
8324 : */
8325 : static void
8326 160 : fetch_more_data_begin(AsyncRequest *areq)
8327 : {
8328 160 : ForeignScanState *node = (ForeignScanState *) areq->requestee;
8329 160 : PgFdwScanState *fsstate = (PgFdwScanState *) node->fdw_state;
8330 : char sql[64];
8331 :
8332 : Assert(!fsstate->conn_state->pendingAreq);
8333 :
8334 : /* Create the cursor synchronously. */
8335 160 : if (!fsstate->cursor_exists)
8336 68 : create_cursor(node);
8337 :
8338 : /* We will send this query, but not wait for the response. */
8339 159 : snprintf(sql, sizeof(sql), "FETCH %d FROM c%u",
8340 : fsstate->fetch_size, fsstate->cursor_number);
8341 :
8342 159 : if (!PQsendQuery(fsstate->conn, sql))
8343 0 : pgfdw_report_error(NULL, fsstate->conn, fsstate->query);
8344 :
8345 : /* Remember that the request is in process */
8346 159 : fsstate->conn_state->pendingAreq = areq;
8347 159 : }
8348 :
8349 : /*
8350 : * Process a pending asynchronous request.
8351 : */
8352 : void
8353 9 : process_pending_request(AsyncRequest *areq)
8354 : {
8355 9 : ForeignScanState *node = (ForeignScanState *) areq->requestee;
8356 9 : PgFdwScanState *fsstate = (PgFdwScanState *) node->fdw_state;
8357 :
8358 : /* The request would have been pending for a callback */
8359 : Assert(areq->callback_pending);
8360 :
8361 : /* The request should be currently in-process */
8362 : Assert(fsstate->conn_state->pendingAreq == areq);
8363 :
8364 9 : fetch_more_data(node);
8365 :
8366 : /*
8367 : * If we didn't get any tuples, must be end of data; complete the request
8368 : * now. Otherwise, we postpone completing the request until we are called
8369 : * from postgresForeignAsyncConfigureWait()/postgresForeignAsyncNotify().
8370 : */
8371 9 : if (fsstate->next_tuple >= fsstate->num_tuples)
8372 : {
8373 : /* Unlike AsyncNotify, we unset callback_pending ourselves */
8374 0 : areq->callback_pending = false;
8375 : /* Mark the request as complete */
8376 0 : ExecAsyncRequestDone(areq, NULL);
8377 : /* Unlike AsyncNotify, we call ExecAsyncResponse ourselves */
8378 0 : ExecAsyncResponse(areq);
8379 : }
8380 9 : }
8381 :
8382 : /*
8383 : * Complete a pending asynchronous request.
8384 : */
8385 : static void
8386 5 : complete_pending_request(AsyncRequest *areq)
8387 : {
8388 : /* The request would have been pending for a callback */
8389 : Assert(areq->callback_pending);
8390 :
8391 : /* Unlike AsyncNotify, we unset callback_pending ourselves */
8392 5 : areq->callback_pending = false;
8393 :
8394 : /* We begin a fetch afterwards if necessary; don't fetch */
8395 5 : produce_tuple_asynchronously(areq, false);
8396 :
8397 : /* Unlike AsyncNotify, we call ExecAsyncResponse ourselves */
8398 5 : ExecAsyncResponse(areq);
8399 :
8400 : /* Also, we do instrumentation ourselves, if required */
8401 5 : if (areq->requestee->instrument)
8402 1 : InstrUpdateTupleCount(areq->requestee->instrument,
8403 1 : TupIsNull(areq->result) ? 0.0 : 1.0);
8404 5 : }
8405 :
8406 : /*
8407 : * Create a tuple from the specified row of the PGresult.
8408 : *
8409 : * rel is the local representation of the foreign table, attinmeta is
8410 : * conversion data for the rel's tupdesc, and retrieved_attrs is an
8411 : * integer list of the table column numbers present in the PGresult.
8412 : * fsstate is the ForeignScan plan node's execution state.
8413 : * temp_context is a working context that can be reset after each tuple.
8414 : *
8415 : * Note: either rel or fsstate, but not both, can be NULL. rel is NULL
8416 : * if we're processing a remote join, while fsstate is NULL in a non-query
8417 : * context such as ANALYZE, or if we're processing a non-scan query node.
8418 : */
8419 : static HeapTuple
8420 94536 : make_tuple_from_result_row(PGresult *res,
8421 : int row,
8422 : Relation rel,
8423 : AttInMetadata *attinmeta,
8424 : List *retrieved_attrs,
8425 : ForeignScanState *fsstate,
8426 : MemoryContext temp_context)
8427 : {
8428 : HeapTuple tuple;
8429 : TupleDesc tupdesc;
8430 : Datum *values;
8431 : bool *nulls;
8432 94536 : ItemPointer ctid = NULL;
8433 : ConversionLocation errpos;
8434 : ErrorContextCallback errcallback;
8435 : MemoryContext oldcontext;
8436 : ListCell *lc;
8437 : int j;
8438 :
8439 : Assert(row < PQntuples(res));
8440 :
8441 : /*
8442 : * Do the following work in a temp context that we reset after each tuple.
8443 : * This cleans up not only the data we have direct access to, but any
8444 : * cruft the I/O functions might leak.
8445 : */
8446 94536 : oldcontext = MemoryContextSwitchTo(temp_context);
8447 :
8448 : /*
8449 : * Get the tuple descriptor for the row. Use the rel's tupdesc if rel is
8450 : * provided, otherwise look to the scan node's ScanTupleSlot.
8451 : */
8452 94536 : if (rel)
8453 58585 : tupdesc = RelationGetDescr(rel);
8454 : else
8455 : {
8456 : Assert(fsstate);
8457 35951 : tupdesc = fsstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor;
8458 : }
8459 :
8460 94536 : values = (Datum *) palloc0(tupdesc->natts * sizeof(Datum));
8461 94536 : nulls = (bool *) palloc(tupdesc->natts * sizeof(bool));
8462 : /* Initialize to nulls for any columns not present in result */
8463 94536 : memset(nulls, true, tupdesc->natts * sizeof(bool));
8464 :
8465 : /*
8466 : * Set up and install callback to report where conversion error occurs.
8467 : */
8468 94536 : errpos.cur_attno = 0;
8469 94536 : errpos.rel = rel;
8470 94536 : errpos.fsstate = fsstate;
8471 94536 : errcallback.callback = conversion_error_callback;
8472 94536 : errcallback.arg = &errpos;
8473 94536 : errcallback.previous = error_context_stack;
8474 94536 : error_context_stack = &errcallback;
8475 :
8476 : /*
8477 : * i indexes columns in the relation, j indexes columns in the PGresult.
8478 : */
8479 94536 : j = 0;
8480 355017 : foreach(lc, retrieved_attrs)
8481 : {
8482 260486 : int i = lfirst_int(lc);
8483 : char *valstr;
8484 :
8485 : /* fetch next column's textual value */
8486 260486 : if (PQgetisnull(res, row, j))
8487 10753 : valstr = NULL;
8488 : else
8489 249733 : valstr = PQgetvalue(res, row, j);
8490 :
8491 : /*
8492 : * convert value to internal representation
8493 : *
8494 : * Note: we ignore system columns other than ctid and oid in result
8495 : */
8496 260486 : errpos.cur_attno = i;
8497 260486 : if (i > 0)
8498 : {
8499 : /* ordinary column */
8500 : Assert(i <= tupdesc->natts);
8501 257369 : nulls[i - 1] = (valstr == NULL);
8502 : /* Apply the input function even to nulls, to support domains */
8503 257364 : values[i - 1] = InputFunctionCall(&attinmeta->attinfuncs[i - 1],
8504 : valstr,
8505 257369 : attinmeta->attioparams[i - 1],
8506 257369 : attinmeta->atttypmods[i - 1]);
8507 : }
8508 3117 : else if (i == SelfItemPointerAttributeNumber)
8509 : {
8510 : /* ctid */
8511 3117 : if (valstr != NULL)
8512 : {
8513 : Datum datum;
8514 :
8515 3117 : datum = DirectFunctionCall1(tidin, CStringGetDatum(valstr));
8516 3117 : ctid = (ItemPointer) DatumGetPointer(datum);
8517 : }
8518 : }
8519 260481 : errpos.cur_attno = 0;
8520 :
8521 260481 : j++;
8522 : }
8523 :
8524 : /* Uninstall error context callback. */
8525 94531 : error_context_stack = errcallback.previous;
8526 :
8527 : /*
8528 : * Check we got the expected number of columns. Note: j == 0 and
8529 : * PQnfields == 1 is expected, since deparse emits a NULL if no columns.
8530 : */
8531 94531 : if (j > 0 && j != PQnfields(res))
8532 0 : elog(ERROR, "remote query result does not match the foreign table");
8533 :
8534 : /*
8535 : * Build the result tuple in caller's memory context.
8536 : */
8537 94531 : MemoryContextSwitchTo(oldcontext);
8538 :
8539 94531 : tuple = heap_form_tuple(tupdesc, values, nulls);
8540 :
8541 : /*
8542 : * If we have a CTID to return, install it in both t_self and t_ctid.
8543 : * t_self is the normal place, but if the tuple is converted to a
8544 : * composite Datum, t_self will be lost; setting t_ctid allows CTID to be
8545 : * preserved during EvalPlanQual re-evaluations (see ROW_MARK_COPY code).
8546 : */
8547 94531 : if (ctid)
8548 3117 : tuple->t_self = tuple->t_data->t_ctid = *ctid;
8549 :
8550 : /*
8551 : * Stomp on the xmin, xmax, and cmin fields from the tuple created by
8552 : * heap_form_tuple. heap_form_tuple actually creates the tuple with
8553 : * DatumTupleFields, not HeapTupleFields, but the executor expects
8554 : * HeapTupleFields and will happily extract system columns on that
8555 : * assumption. If we don't do this then, for example, the tuple length
8556 : * ends up in the xmin field, which isn't what we want.
8557 : */
8558 94531 : HeapTupleHeaderSetXmax(tuple->t_data, InvalidTransactionId);
8559 94531 : HeapTupleHeaderSetXmin(tuple->t_data, InvalidTransactionId);
8560 94531 : HeapTupleHeaderSetCmin(tuple->t_data, InvalidTransactionId);
8561 :
8562 : /* Clean up */
8563 94531 : MemoryContextReset(temp_context);
8564 :
8565 94531 : return tuple;
8566 : }
8567 :
8568 : /*
8569 : * Callback function which is called when error occurs during column value
8570 : * conversion. Print names of column and relation.
8571 : *
8572 : * Note that this function mustn't do any catalog lookups, since we are in
8573 : * an already-failed transaction. Fortunately, we can get the needed info
8574 : * from the relation or the query's rangetable instead.
8575 : */
8576 : static void
8577 5 : conversion_error_callback(void *arg)
8578 : {
8579 5 : ConversionLocation *errpos = (ConversionLocation *) arg;
8580 5 : Relation rel = errpos->rel;
8581 5 : ForeignScanState *fsstate = errpos->fsstate;
8582 5 : const char *attname = NULL;
8583 5 : const char *relname = NULL;
8584 5 : bool is_wholerow = false;
8585 :
8586 : /*
8587 : * If we're in a scan node, always use aliases from the rangetable, for
8588 : * consistency between the simple-relation and remote-join cases. Look at
8589 : * the relation's tupdesc only if we're not in a scan node.
8590 : */
8591 5 : if (fsstate)
8592 : {
8593 : /* ForeignScan case */
8594 4 : ForeignScan *fsplan = castNode(ForeignScan, fsstate->ss.ps.plan);
8595 4 : int varno = 0;
8596 4 : AttrNumber colno = 0;
8597 :
8598 4 : if (fsplan->scan.scanrelid > 0)
8599 : {
8600 : /* error occurred in a scan against a foreign table */
8601 1 : varno = fsplan->scan.scanrelid;
8602 1 : colno = errpos->cur_attno;
8603 : }
8604 : else
8605 : {
8606 : /* error occurred in a scan against a foreign join */
8607 : TargetEntry *tle;
8608 :
8609 3 : tle = list_nth_node(TargetEntry, fsplan->fdw_scan_tlist,
8610 : errpos->cur_attno - 1);
8611 :
8612 : /*
8613 : * Target list can have Vars and expressions. For Vars, we can
8614 : * get some information, however for expressions we can't. Thus
8615 : * for expressions, just show generic context message.
8616 : */
8617 3 : if (IsA(tle->expr, Var))
8618 : {
8619 2 : Var *var = (Var *) tle->expr;
8620 :
8621 2 : varno = var->varno;
8622 2 : colno = var->varattno;
8623 : }
8624 : }
8625 :
8626 4 : if (varno > 0)
8627 : {
8628 3 : EState *estate = fsstate->ss.ps.state;
8629 3 : RangeTblEntry *rte = exec_rt_fetch(varno, estate);
8630 :
8631 3 : relname = rte->eref->aliasname;
8632 :
8633 3 : if (colno == 0)
8634 1 : is_wholerow = true;
8635 2 : else if (colno > 0 && colno <= list_length(rte->eref->colnames))
8636 2 : attname = strVal(list_nth(rte->eref->colnames, colno - 1));
8637 0 : else if (colno == SelfItemPointerAttributeNumber)
8638 0 : attname = "ctid";
8639 : }
8640 : }
8641 1 : else if (rel)
8642 : {
8643 : /* Non-ForeignScan case (we should always have a rel here) */
8644 1 : TupleDesc tupdesc = RelationGetDescr(rel);
8645 :
8646 1 : relname = RelationGetRelationName(rel);
8647 1 : if (errpos->cur_attno > 0 && errpos->cur_attno <= tupdesc->natts)
8648 1 : {
8649 1 : Form_pg_attribute attr = TupleDescAttr(tupdesc,
8650 1 : errpos->cur_attno - 1);
8651 :
8652 1 : attname = NameStr(attr->attname);
8653 : }
8654 0 : else if (errpos->cur_attno == SelfItemPointerAttributeNumber)
8655 0 : attname = "ctid";
8656 : }
8657 :
8658 5 : if (relname && is_wholerow)
8659 1 : errcontext("whole-row reference to foreign table \"%s\"", relname);
8660 4 : else if (relname && attname)
8661 3 : errcontext("column \"%s\" of foreign table \"%s\"", attname, relname);
8662 : else
8663 1 : errcontext("processing expression at position %d in select list",
8664 1 : errpos->cur_attno);
8665 5 : }
8666 :
8667 : /*
8668 : * Given an EquivalenceClass and a foreign relation, find an EC member
8669 : * that can be used to sort the relation remotely according to a pathkey
8670 : * using this EC.
8671 : *
8672 : * If there is more than one suitable candidate, return an arbitrary
8673 : * one of them. If there is none, return NULL.
8674 : *
8675 : * This checks that the EC member expression uses only Vars from the given
8676 : * rel and is shippable. Caller must separately verify that the pathkey's
8677 : * ordering operator is shippable.
8678 : */
8679 : EquivalenceMember *
8680 1827 : find_em_for_rel(PlannerInfo *root, EquivalenceClass *ec, RelOptInfo *rel)
8681 : {
8682 1827 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private;
8683 : EquivalenceMemberIterator it;
8684 : EquivalenceMember *em;
8685 :
8686 1827 : setup_eclass_member_iterator(&it, ec, rel->relids);
8687 3054 : while ((em = eclass_member_iterator_next(&it)) != NULL)
8688 : {
8689 : /*
8690 : * Note we require !bms_is_empty, else we'd accept constant
8691 : * expressions which are not suitable for the purpose.
8692 : */
8693 2774 : if (bms_is_subset(em->em_relids, rel->relids) &&
8694 3151 : !bms_is_empty(em->em_relids) &&
8695 3138 : bms_is_empty(bms_intersect(em->em_relids, fpinfo->hidden_subquery_rels)) &&
8696 1563 : is_foreign_expr(root, rel, em->em_expr))
8697 1547 : return em;
8698 : }
8699 :
8700 280 : return NULL;
8701 : }
8702 :
8703 : /*
8704 : * Find an EquivalenceClass member that is to be computed as a sort column
8705 : * in the given rel's reltarget, and is shippable.
8706 : *
8707 : * If there is more than one suitable candidate, return an arbitrary
8708 : * one of them. If there is none, return NULL.
8709 : *
8710 : * This checks that the EC member expression uses only Vars from the given
8711 : * rel and is shippable. Caller must separately verify that the pathkey's
8712 : * ordering operator is shippable.
8713 : */
8714 : EquivalenceMember *
8715 255 : find_em_for_rel_target(PlannerInfo *root, EquivalenceClass *ec,
8716 : RelOptInfo *rel)
8717 : {
8718 255 : PathTarget *target = rel->reltarget;
8719 : ListCell *lc1;
8720 : int i;
8721 :
8722 255 : i = 0;
8723 425 : foreach(lc1, target->exprs)
8724 : {
8725 425 : Expr *expr = (Expr *) lfirst(lc1);
8726 425 : Index sgref = get_pathtarget_sortgroupref(target, i);
8727 : ListCell *lc2;
8728 :
8729 : /* Ignore non-sort expressions */
8730 765 : if (sgref == 0 ||
8731 340 : get_sortgroupref_clause_noerr(sgref,
8732 340 : root->parse->sortClause) == NULL)
8733 : {
8734 93 : i++;
8735 93 : continue;
8736 : }
8737 :
8738 : /* We ignore binary-compatible relabeling on both ends */
8739 332 : while (expr && IsA(expr, RelabelType))
8740 0 : expr = ((RelabelType *) expr)->arg;
8741 :
8742 : /*
8743 : * Locate an EquivalenceClass member matching this expr, if any.
8744 : * Ignore child members.
8745 : */
8746 413 : foreach(lc2, ec->ec_members)
8747 : {
8748 336 : EquivalenceMember *em = (EquivalenceMember *) lfirst(lc2);
8749 : Expr *em_expr;
8750 :
8751 : /* Don't match constants */
8752 336 : if (em->em_is_const)
8753 0 : continue;
8754 :
8755 : /* Child members should not exist in ec_members */
8756 : Assert(!em->em_is_child);
8757 :
8758 : /* Match if same expression (after stripping relabel) */
8759 336 : em_expr = em->em_expr;
8760 348 : while (em_expr && IsA(em_expr, RelabelType))
8761 12 : em_expr = ((RelabelType *) em_expr)->arg;
8762 :
8763 336 : if (!equal(em_expr, expr))
8764 81 : continue;
8765 :
8766 : /* Check that expression (including relabels!) is shippable */
8767 255 : if (is_foreign_expr(root, rel, em->em_expr))
8768 255 : return em;
8769 : }
8770 :
8771 77 : i++;
8772 : }
8773 :
8774 0 : return NULL;
8775 : }
8776 :
8777 : /*
8778 : * Determine batch size for a given foreign table. The option specified for
8779 : * a table has precedence.
8780 : */
8781 : static int
8782 146 : get_batch_size_option(Relation rel)
8783 : {
8784 146 : Oid foreigntableid = RelationGetRelid(rel);
8785 : ForeignTable *table;
8786 : ForeignServer *server;
8787 : List *options;
8788 : ListCell *lc;
8789 :
8790 : /* we use 1 by default, which means "no batching" */
8791 146 : int batch_size = 1;
8792 :
8793 : /*
8794 : * Load options for table and server. We append server options after table
8795 : * options, because table options take precedence.
8796 : */
8797 146 : table = GetForeignTable(foreigntableid);
8798 146 : server = GetForeignServer(table->serverid);
8799 :
8800 146 : options = NIL;
8801 146 : options = list_concat(options, table->options);
8802 146 : options = list_concat(options, server->options);
8803 :
8804 : /* See if either table or server specifies batch_size. */
8805 766 : foreach(lc, options)
8806 : {
8807 655 : DefElem *def = (DefElem *) lfirst(lc);
8808 :
8809 655 : if (strcmp(def->defname, "batch_size") == 0)
8810 : {
8811 35 : (void) parse_int(defGetString(def), &batch_size, 0, NULL);
8812 35 : break;
8813 : }
8814 : }
8815 :
8816 146 : return batch_size;
8817 : }
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