Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * deparse.c
4 : * Query deparser for postgres_fdw
5 : *
6 : * This file includes functions that examine query WHERE clauses to see
7 : * whether they're safe to send to the remote server for execution, as
8 : * well as functions to construct the query text to be sent. The latter
9 : * functionality is annoyingly duplicative of ruleutils.c, but there are
10 : * enough special considerations that it seems best to keep this separate.
11 : * One saving grace is that we only need deparse logic for node types that
12 : * we consider safe to send.
13 : *
14 : * We assume that the remote session's search_path is exactly "pg_catalog",
15 : * and thus we need schema-qualify all and only names outside pg_catalog.
16 : *
17 : * We do not consider that it is ever safe to send COLLATE expressions to
18 : * the remote server: it might not have the same collation names we do.
19 : * (Later we might consider it safe to send COLLATE "C", but even that would
20 : * fail on old remote servers.) An expression is considered safe to send
21 : * only if all operator/function input collations used in it are traceable to
22 : * Var(s) of the foreign table. That implies that if the remote server gets
23 : * a different answer than we do, the foreign table's columns are not marked
24 : * with collations that match the remote table's columns, which we can
25 : * consider to be user error.
26 : *
27 : * Portions Copyright (c) 2012-2021, PostgreSQL Global Development Group
28 : *
29 : * IDENTIFICATION
30 : * contrib/postgres_fdw/deparse.c
31 : *
32 : *-------------------------------------------------------------------------
33 : */
34 : #include "postgres.h"
35 :
36 : #include "access/htup_details.h"
37 : #include "access/sysattr.h"
38 : #include "access/table.h"
39 : #include "catalog/pg_aggregate.h"
40 : #include "catalog/pg_collation.h"
41 : #include "catalog/pg_namespace.h"
42 : #include "catalog/pg_operator.h"
43 : #include "catalog/pg_proc.h"
44 : #include "catalog/pg_type.h"
45 : #include "commands/defrem.h"
46 : #include "nodes/makefuncs.h"
47 : #include "nodes/nodeFuncs.h"
48 : #include "nodes/plannodes.h"
49 : #include "optimizer/optimizer.h"
50 : #include "optimizer/prep.h"
51 : #include "optimizer/tlist.h"
52 : #include "parser/parsetree.h"
53 : #include "postgres_fdw.h"
54 : #include "utils/builtins.h"
55 : #include "utils/lsyscache.h"
56 : #include "utils/rel.h"
57 : #include "utils/syscache.h"
58 : #include "utils/typcache.h"
59 :
60 : /*
61 : * Global context for foreign_expr_walker's search of an expression tree.
62 : */
63 : typedef struct foreign_glob_cxt
64 : {
65 : PlannerInfo *root; /* global planner state */
66 : RelOptInfo *foreignrel; /* the foreign relation we are planning for */
67 : Relids relids; /* relids of base relations in the underlying
68 : * scan */
69 : } foreign_glob_cxt;
70 :
71 : /*
72 : * Local (per-tree-level) context for foreign_expr_walker's search.
73 : * This is concerned with identifying collations used in the expression.
74 : */
75 : typedef enum
76 : {
77 : FDW_COLLATE_NONE, /* expression is of a noncollatable type, or
78 : * it has default collation that is not
79 : * traceable to a foreign Var */
80 : FDW_COLLATE_SAFE, /* collation derives from a foreign Var */
81 : FDW_COLLATE_UNSAFE /* collation is non-default and derives from
82 : * something other than a foreign Var */
83 : } FDWCollateState;
84 :
85 : typedef struct foreign_loc_cxt
86 : {
87 : Oid collation; /* OID of current collation, if any */
88 : FDWCollateState state; /* state of current collation choice */
89 : } foreign_loc_cxt;
90 :
91 : /*
92 : * Context for deparseExpr
93 : */
94 : typedef struct deparse_expr_cxt
95 : {
96 : PlannerInfo *root; /* global planner state */
97 : RelOptInfo *foreignrel; /* the foreign relation we are planning for */
98 : RelOptInfo *scanrel; /* the underlying scan relation. Same as
99 : * foreignrel, when that represents a join or
100 : * a base relation. */
101 : StringInfo buf; /* output buffer to append to */
102 : List **params_list; /* exprs that will become remote Params */
103 : } deparse_expr_cxt;
104 :
105 : #define REL_ALIAS_PREFIX "r"
106 : /* Handy macro to add relation name qualification */
107 : #define ADD_REL_QUALIFIER(buf, varno) \
108 : appendStringInfo((buf), "%s%d.", REL_ALIAS_PREFIX, (varno))
109 : #define SUBQUERY_REL_ALIAS_PREFIX "s"
110 : #define SUBQUERY_COL_ALIAS_PREFIX "c"
111 :
112 : /*
113 : * Functions to determine whether an expression can be evaluated safely on
114 : * remote server.
115 : */
116 : static bool foreign_expr_walker(Node *node,
117 : foreign_glob_cxt *glob_cxt,
118 : foreign_loc_cxt *outer_cxt);
119 : static char *deparse_type_name(Oid type_oid, int32 typemod);
120 :
121 : /*
122 : * Functions to construct string representation of a node tree.
123 : */
124 : static void deparseTargetList(StringInfo buf,
125 : RangeTblEntry *rte,
126 : Index rtindex,
127 : Relation rel,
128 : bool is_returning,
129 : Bitmapset *attrs_used,
130 : bool qualify_col,
131 : List **retrieved_attrs);
132 : static void deparseExplicitTargetList(List *tlist,
133 : bool is_returning,
134 : List **retrieved_attrs,
135 : deparse_expr_cxt *context);
136 : static void deparseSubqueryTargetList(deparse_expr_cxt *context);
137 : static void deparseReturningList(StringInfo buf, RangeTblEntry *rte,
138 : Index rtindex, Relation rel,
139 : bool trig_after_row,
140 : List *withCheckOptionList,
141 : List *returningList,
142 : List **retrieved_attrs);
143 : static void deparseColumnRef(StringInfo buf, int varno, int varattno,
144 : RangeTblEntry *rte, bool qualify_col);
145 : static void deparseRelation(StringInfo buf, Relation rel);
146 : static void deparseExpr(Expr *expr, deparse_expr_cxt *context);
147 : static void deparseVar(Var *node, deparse_expr_cxt *context);
148 : static void deparseConst(Const *node, deparse_expr_cxt *context, int showtype);
149 : static void deparseParam(Param *node, deparse_expr_cxt *context);
150 : static void deparseSubscriptingRef(SubscriptingRef *node, deparse_expr_cxt *context);
151 : static void deparseFuncExpr(FuncExpr *node, deparse_expr_cxt *context);
152 : static void deparseOpExpr(OpExpr *node, deparse_expr_cxt *context);
153 : static void deparseOperatorName(StringInfo buf, Form_pg_operator opform);
154 : static void deparseDistinctExpr(DistinctExpr *node, deparse_expr_cxt *context);
155 : static void deparseScalarArrayOpExpr(ScalarArrayOpExpr *node,
156 : deparse_expr_cxt *context);
157 : static void deparseRelabelType(RelabelType *node, deparse_expr_cxt *context);
158 : static void deparseBoolExpr(BoolExpr *node, deparse_expr_cxt *context);
159 : static void deparseNullTest(NullTest *node, deparse_expr_cxt *context);
160 : static void deparseArrayExpr(ArrayExpr *node, deparse_expr_cxt *context);
161 : static void printRemoteParam(int paramindex, Oid paramtype, int32 paramtypmod,
162 : deparse_expr_cxt *context);
163 : static void printRemotePlaceholder(Oid paramtype, int32 paramtypmod,
164 : deparse_expr_cxt *context);
165 : static void deparseSelectSql(List *tlist, bool is_subquery, List **retrieved_attrs,
166 : deparse_expr_cxt *context);
167 : static void deparseLockingClause(deparse_expr_cxt *context);
168 : static void appendOrderByClause(List *pathkeys, bool has_final_sort,
169 : deparse_expr_cxt *context);
170 : static void appendLimitClause(deparse_expr_cxt *context);
171 : static void appendConditions(List *exprs, deparse_expr_cxt *context);
172 : static void deparseFromExprForRel(StringInfo buf, PlannerInfo *root,
173 : RelOptInfo *foreignrel, bool use_alias,
174 : Index ignore_rel, List **ignore_conds,
175 : List **params_list);
176 : static void deparseFromExpr(List *quals, deparse_expr_cxt *context);
177 : static void deparseRangeTblRef(StringInfo buf, PlannerInfo *root,
178 : RelOptInfo *foreignrel, bool make_subquery,
179 : Index ignore_rel, List **ignore_conds, List **params_list);
180 : static void deparseAggref(Aggref *node, deparse_expr_cxt *context);
181 : static void appendGroupByClause(List *tlist, deparse_expr_cxt *context);
182 : static void appendAggOrderBy(List *orderList, List *targetList,
183 : deparse_expr_cxt *context);
184 : static void appendFunctionName(Oid funcid, deparse_expr_cxt *context);
185 : static Node *deparseSortGroupClause(Index ref, List *tlist, bool force_colno,
186 : deparse_expr_cxt *context);
187 :
188 : /*
189 : * Helper functions
190 : */
191 : static bool is_subquery_var(Var *node, RelOptInfo *foreignrel,
192 : int *relno, int *colno);
193 : static void get_relation_column_alias_ids(Var *node, RelOptInfo *foreignrel,
194 : int *relno, int *colno);
195 :
196 :
197 : /*
198 : * Examine each qual clause in input_conds, and classify them into two groups,
199 : * which are returned as two lists:
200 : * - remote_conds contains expressions that can be evaluated remotely
201 : * - local_conds contains expressions that can't be evaluated remotely
202 : */
203 : void
204 3508 : classifyConditions(PlannerInfo *root,
205 : RelOptInfo *baserel,
206 : List *input_conds,
207 : List **remote_conds,
208 : List **local_conds)
209 : {
210 : ListCell *lc;
211 :
212 3508 : *remote_conds = NIL;
213 3508 : *local_conds = NIL;
214 :
215 4596 : foreach(lc, input_conds)
216 : {
217 1088 : RestrictInfo *ri = lfirst_node(RestrictInfo, lc);
218 :
219 1088 : if (is_foreign_expr(root, baserel, ri->clause))
220 1012 : *remote_conds = lappend(*remote_conds, ri);
221 : else
222 76 : *local_conds = lappend(*local_conds, ri);
223 : }
224 3508 : }
225 :
226 : /*
227 : * Returns true if given expr is safe to evaluate on the foreign server.
228 : */
229 : bool
230 4428 : is_foreign_expr(PlannerInfo *root,
231 : RelOptInfo *baserel,
232 : Expr *expr)
233 : {
234 : foreign_glob_cxt glob_cxt;
235 : foreign_loc_cxt loc_cxt;
236 4428 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) (baserel->fdw_private);
237 :
238 : /*
239 : * Check that the expression consists of nodes that are safe to execute
240 : * remotely.
241 : */
242 4428 : glob_cxt.root = root;
243 4428 : glob_cxt.foreignrel = baserel;
244 :
245 : /*
246 : * For an upper relation, use relids from its underneath scan relation,
247 : * because the upperrel's own relids currently aren't set to anything
248 : * meaningful by the core code. For other relation, use their own relids.
249 : */
250 4428 : if (IS_UPPER_REL(baserel))
251 748 : glob_cxt.relids = fpinfo->outerrel->relids;
252 : else
253 3680 : glob_cxt.relids = baserel->relids;
254 4428 : loc_cxt.collation = InvalidOid;
255 4428 : loc_cxt.state = FDW_COLLATE_NONE;
256 4428 : if (!foreign_expr_walker((Node *) expr, &glob_cxt, &loc_cxt))
257 210 : return false;
258 :
259 : /*
260 : * If the expression has a valid collation that does not arise from a
261 : * foreign var, the expression can not be sent over.
262 : */
263 4218 : if (loc_cxt.state == FDW_COLLATE_UNSAFE)
264 4 : return false;
265 :
266 : /*
267 : * An expression which includes any mutable functions can't be sent over
268 : * because its result is not stable. For example, sending now() remote
269 : * side could cause confusion from clock offsets. Future versions might
270 : * be able to make this choice with more granularity. (We check this last
271 : * because it requires a lot of expensive catalog lookups.)
272 : */
273 4214 : if (contain_mutable_functions((Node *) expr))
274 42 : return false;
275 :
276 : /* OK to evaluate on the remote server */
277 4172 : return true;
278 : }
279 :
280 : /*
281 : * Check if expression is safe to execute remotely, and return true if so.
282 : *
283 : * In addition, *outer_cxt is updated with collation information.
284 : *
285 : * We must check that the expression contains only node types we can deparse,
286 : * that all types/functions/operators are safe to send (they are "shippable"),
287 : * and that all collations used in the expression derive from Vars of the
288 : * foreign table. Because of the latter, the logic is pretty close to
289 : * assign_collations_walker() in parse_collate.c, though we can assume here
290 : * that the given expression is valid. Note function mutability is not
291 : * currently considered here.
292 : */
293 : static bool
294 12778 : foreign_expr_walker(Node *node,
295 : foreign_glob_cxt *glob_cxt,
296 : foreign_loc_cxt *outer_cxt)
297 : {
298 12778 : bool check_type = true;
299 : PgFdwRelationInfo *fpinfo;
300 : foreign_loc_cxt inner_cxt;
301 : Oid collation;
302 : FDWCollateState state;
303 :
304 : /* Need do nothing for empty subexpressions */
305 12778 : if (node == NULL)
306 502 : return true;
307 :
308 : /* May need server info from baserel's fdw_private struct */
309 12276 : fpinfo = (PgFdwRelationInfo *) (glob_cxt->foreignrel->fdw_private);
310 :
311 : /* Set up inner_cxt for possible recursion to child nodes */
312 12276 : inner_cxt.collation = InvalidOid;
313 12276 : inner_cxt.state = FDW_COLLATE_NONE;
314 :
315 12276 : switch (nodeTag(node))
316 : {
317 4986 : case T_Var:
318 : {
319 4986 : Var *var = (Var *) node;
320 :
321 : /*
322 : * If the Var is from the foreign table, we consider its
323 : * collation (if any) safe to use. If it is from another
324 : * table, we treat its collation the same way as we would a
325 : * Param's collation, ie it's not safe for it to have a
326 : * non-default collation.
327 : */
328 4986 : if (bms_is_member(var->varno, glob_cxt->relids) &&
329 4394 : var->varlevelsup == 0)
330 : {
331 : /* Var belongs to foreign table */
332 :
333 : /*
334 : * System columns other than ctid should not be sent to
335 : * the remote, since we don't make any effort to ensure
336 : * that local and remote values match (tableoid, in
337 : * particular, almost certainly doesn't match).
338 : */
339 4394 : if (var->varattno < 0 &&
340 16 : var->varattno != SelfItemPointerAttributeNumber)
341 12 : return false;
342 :
343 : /* Else check the collation */
344 4382 : collation = var->varcollid;
345 4382 : state = OidIsValid(collation) ? FDW_COLLATE_SAFE : FDW_COLLATE_NONE;
346 : }
347 : else
348 : {
349 : /* Var belongs to some other table */
350 592 : collation = var->varcollid;
351 592 : if (collation == InvalidOid ||
352 : collation == DEFAULT_COLLATION_OID)
353 : {
354 : /*
355 : * It's noncollatable, or it's safe to combine with a
356 : * collatable foreign Var, so set state to NONE.
357 : */
358 592 : state = FDW_COLLATE_NONE;
359 : }
360 : else
361 : {
362 : /*
363 : * Do not fail right away, since the Var might appear
364 : * in a collation-insensitive context.
365 : */
366 0 : state = FDW_COLLATE_UNSAFE;
367 : }
368 : }
369 : }
370 4974 : break;
371 1444 : case T_Const:
372 : {
373 1444 : Const *c = (Const *) node;
374 :
375 : /*
376 : * If the constant has nondefault collation, either it's of a
377 : * non-builtin type, or it reflects folding of a CollateExpr.
378 : * It's unsafe to send to the remote unless it's used in a
379 : * non-collation-sensitive context.
380 : */
381 1444 : collation = c->constcollid;
382 1444 : if (collation == InvalidOid ||
383 : collation == DEFAULT_COLLATION_OID)
384 1440 : state = FDW_COLLATE_NONE;
385 : else
386 4 : state = FDW_COLLATE_UNSAFE;
387 : }
388 1444 : break;
389 46 : case T_Param:
390 : {
391 46 : Param *p = (Param *) node;
392 :
393 : /*
394 : * If it's a MULTIEXPR Param, punt. We can't tell from here
395 : * whether the referenced sublink/subplan contains any remote
396 : * Vars; if it does, handling that is too complicated to
397 : * consider supporting at present. Fortunately, MULTIEXPR
398 : * Params are not reduced to plain PARAM_EXEC until the end of
399 : * planning, so we can easily detect this case. (Normal
400 : * PARAM_EXEC Params are safe to ship because their values
401 : * come from somewhere else in the plan tree; but a MULTIEXPR
402 : * references a sub-select elsewhere in the same targetlist,
403 : * so we'd be on the hook to evaluate it somehow if we wanted
404 : * to handle such cases as direct foreign updates.)
405 : */
406 46 : if (p->paramkind == PARAM_MULTIEXPR)
407 6 : return false;
408 :
409 : /*
410 : * Collation rule is same as for Consts and non-foreign Vars.
411 : */
412 40 : collation = p->paramcollid;
413 40 : if (collation == InvalidOid ||
414 : collation == DEFAULT_COLLATION_OID)
415 40 : state = FDW_COLLATE_NONE;
416 : else
417 0 : state = FDW_COLLATE_UNSAFE;
418 : }
419 40 : break;
420 2 : case T_SubscriptingRef:
421 : {
422 2 : SubscriptingRef *sr = (SubscriptingRef *) node;
423 :
424 : /* Assignment should not be in restrictions. */
425 2 : if (sr->refassgnexpr != NULL)
426 0 : return false;
427 :
428 : /*
429 : * Recurse into the remaining subexpressions. The container
430 : * subscripts will not affect collation of the SubscriptingRef
431 : * result, so do those first and reset inner_cxt afterwards.
432 : */
433 2 : if (!foreign_expr_walker((Node *) sr->refupperindexpr,
434 : glob_cxt, &inner_cxt))
435 0 : return false;
436 2 : inner_cxt.collation = InvalidOid;
437 2 : inner_cxt.state = FDW_COLLATE_NONE;
438 2 : if (!foreign_expr_walker((Node *) sr->reflowerindexpr,
439 : glob_cxt, &inner_cxt))
440 0 : return false;
441 2 : inner_cxt.collation = InvalidOid;
442 2 : inner_cxt.state = FDW_COLLATE_NONE;
443 2 : if (!foreign_expr_walker((Node *) sr->refexpr,
444 : glob_cxt, &inner_cxt))
445 0 : return false;
446 :
447 : /*
448 : * Container subscripting typically yields same collation as
449 : * refexpr's, but in case it doesn't, use same logic as for
450 : * function nodes.
451 : */
452 2 : collation = sr->refcollid;
453 2 : if (collation == InvalidOid)
454 2 : state = FDW_COLLATE_NONE;
455 0 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
456 0 : collation == inner_cxt.collation)
457 0 : state = FDW_COLLATE_SAFE;
458 0 : else if (collation == DEFAULT_COLLATION_OID)
459 0 : state = FDW_COLLATE_NONE;
460 : else
461 0 : state = FDW_COLLATE_UNSAFE;
462 : }
463 2 : break;
464 210 : case T_FuncExpr:
465 : {
466 210 : FuncExpr *fe = (FuncExpr *) node;
467 :
468 : /*
469 : * If function used by the expression is not shippable, it
470 : * can't be sent to remote because it might have incompatible
471 : * semantics on remote side.
472 : */
473 210 : if (!is_shippable(fe->funcid, ProcedureRelationId, fpinfo))
474 10 : return false;
475 :
476 : /*
477 : * Recurse to input subexpressions.
478 : */
479 200 : if (!foreign_expr_walker((Node *) fe->args,
480 : glob_cxt, &inner_cxt))
481 12 : return false;
482 :
483 : /*
484 : * If function's input collation is not derived from a foreign
485 : * Var, it can't be sent to remote.
486 : */
487 188 : if (fe->inputcollid == InvalidOid)
488 : /* OK, inputs are all noncollatable */ ;
489 44 : else if (inner_cxt.state != FDW_COLLATE_SAFE ||
490 24 : fe->inputcollid != inner_cxt.collation)
491 20 : return false;
492 :
493 : /*
494 : * Detect whether node is introducing a collation not derived
495 : * from a foreign Var. (If so, we just mark it unsafe for now
496 : * rather than immediately returning false, since the parent
497 : * node might not care.)
498 : */
499 168 : collation = fe->funccollid;
500 168 : if (collation == InvalidOid)
501 144 : state = FDW_COLLATE_NONE;
502 24 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
503 24 : collation == inner_cxt.collation)
504 24 : state = FDW_COLLATE_SAFE;
505 0 : else if (collation == DEFAULT_COLLATION_OID)
506 0 : state = FDW_COLLATE_NONE;
507 : else
508 0 : state = FDW_COLLATE_UNSAFE;
509 : }
510 168 : break;
511 2288 : case T_OpExpr:
512 : case T_DistinctExpr: /* struct-equivalent to OpExpr */
513 : {
514 2288 : OpExpr *oe = (OpExpr *) node;
515 :
516 : /*
517 : * Similarly, only shippable operators can be sent to remote.
518 : * (If the operator is shippable, we assume its underlying
519 : * function is too.)
520 : */
521 2288 : if (!is_shippable(oe->opno, OperatorRelationId, fpinfo))
522 26 : return false;
523 :
524 : /*
525 : * Recurse to input subexpressions.
526 : */
527 2262 : if (!foreign_expr_walker((Node *) oe->args,
528 : glob_cxt, &inner_cxt))
529 76 : return false;
530 :
531 : /*
532 : * If operator's input collation is not derived from a foreign
533 : * Var, it can't be sent to remote.
534 : */
535 2186 : if (oe->inputcollid == InvalidOid)
536 : /* OK, inputs are all noncollatable */ ;
537 104 : else if (inner_cxt.state != FDW_COLLATE_SAFE ||
538 94 : oe->inputcollid != inner_cxt.collation)
539 10 : return false;
540 :
541 : /* Result-collation handling is same as for functions */
542 2176 : collation = oe->opcollid;
543 2176 : if (collation == InvalidOid)
544 2160 : state = FDW_COLLATE_NONE;
545 16 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
546 16 : collation == inner_cxt.collation)
547 16 : state = FDW_COLLATE_SAFE;
548 0 : else if (collation == DEFAULT_COLLATION_OID)
549 0 : state = FDW_COLLATE_NONE;
550 : else
551 0 : state = FDW_COLLATE_UNSAFE;
552 : }
553 2176 : break;
554 6 : case T_ScalarArrayOpExpr:
555 : {
556 6 : ScalarArrayOpExpr *oe = (ScalarArrayOpExpr *) node;
557 :
558 : /*
559 : * Again, only shippable operators can be sent to remote.
560 : */
561 6 : if (!is_shippable(oe->opno, OperatorRelationId, fpinfo))
562 0 : return false;
563 :
564 : /*
565 : * Recurse to input subexpressions.
566 : */
567 6 : if (!foreign_expr_walker((Node *) oe->args,
568 : glob_cxt, &inner_cxt))
569 0 : return false;
570 :
571 : /*
572 : * If operator's input collation is not derived from a foreign
573 : * Var, it can't be sent to remote.
574 : */
575 6 : if (oe->inputcollid == InvalidOid)
576 : /* OK, inputs are all noncollatable */ ;
577 0 : else if (inner_cxt.state != FDW_COLLATE_SAFE ||
578 0 : oe->inputcollid != inner_cxt.collation)
579 0 : return false;
580 :
581 : /* Output is always boolean and so noncollatable. */
582 6 : collation = InvalidOid;
583 6 : state = FDW_COLLATE_NONE;
584 : }
585 6 : break;
586 82 : case T_RelabelType:
587 : {
588 82 : RelabelType *r = (RelabelType *) node;
589 :
590 : /*
591 : * Recurse to input subexpression.
592 : */
593 82 : if (!foreign_expr_walker((Node *) r->arg,
594 : glob_cxt, &inner_cxt))
595 0 : return false;
596 :
597 : /*
598 : * RelabelType must not introduce a collation not derived from
599 : * an input foreign Var (same logic as for a real function).
600 : */
601 82 : collation = r->resultcollid;
602 82 : if (collation == InvalidOid)
603 0 : state = FDW_COLLATE_NONE;
604 82 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
605 74 : collation == inner_cxt.collation)
606 64 : state = FDW_COLLATE_SAFE;
607 18 : else if (collation == DEFAULT_COLLATION_OID)
608 6 : state = FDW_COLLATE_NONE;
609 : else
610 12 : state = FDW_COLLATE_UNSAFE;
611 : }
612 82 : break;
613 72 : case T_BoolExpr:
614 : {
615 72 : BoolExpr *b = (BoolExpr *) node;
616 :
617 : /*
618 : * Recurse to input subexpressions.
619 : */
620 72 : if (!foreign_expr_walker((Node *) b->args,
621 : glob_cxt, &inner_cxt))
622 0 : return false;
623 :
624 : /* Output is always boolean and so noncollatable. */
625 72 : collation = InvalidOid;
626 72 : state = FDW_COLLATE_NONE;
627 : }
628 72 : break;
629 54 : case T_NullTest:
630 : {
631 54 : NullTest *nt = (NullTest *) node;
632 :
633 : /*
634 : * Recurse to input subexpressions.
635 : */
636 54 : if (!foreign_expr_walker((Node *) nt->arg,
637 : glob_cxt, &inner_cxt))
638 0 : return false;
639 :
640 : /* Output is always boolean and so noncollatable. */
641 54 : collation = InvalidOid;
642 54 : state = FDW_COLLATE_NONE;
643 : }
644 54 : break;
645 8 : case T_ArrayExpr:
646 : {
647 8 : ArrayExpr *a = (ArrayExpr *) node;
648 :
649 : /*
650 : * Recurse to input subexpressions.
651 : */
652 8 : if (!foreign_expr_walker((Node *) a->elements,
653 : glob_cxt, &inner_cxt))
654 0 : return false;
655 :
656 : /*
657 : * ArrayExpr must not introduce a collation not derived from
658 : * an input foreign Var (same logic as for a function).
659 : */
660 8 : collation = a->array_collid;
661 8 : if (collation == InvalidOid)
662 8 : state = FDW_COLLATE_NONE;
663 0 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
664 0 : collation == inner_cxt.collation)
665 0 : state = FDW_COLLATE_SAFE;
666 0 : else if (collation == DEFAULT_COLLATION_OID)
667 0 : state = FDW_COLLATE_NONE;
668 : else
669 0 : state = FDW_COLLATE_UNSAFE;
670 : }
671 8 : break;
672 2556 : case T_List:
673 : {
674 2556 : List *l = (List *) node;
675 : ListCell *lc;
676 :
677 : /*
678 : * Recurse to component subexpressions.
679 : */
680 7278 : foreach(lc, l)
681 : {
682 4836 : if (!foreign_expr_walker((Node *) lfirst(lc),
683 : glob_cxt, &inner_cxt))
684 114 : return false;
685 : }
686 :
687 : /*
688 : * When processing a list, collation state just bubbles up
689 : * from the list elements.
690 : */
691 2442 : collation = inner_cxt.collation;
692 2442 : state = inner_cxt.state;
693 :
694 : /* Don't apply exprType() to the list. */
695 2442 : check_type = false;
696 : }
697 2442 : break;
698 462 : case T_Aggref:
699 : {
700 462 : Aggref *agg = (Aggref *) node;
701 : ListCell *lc;
702 :
703 : /* Not safe to pushdown when not in grouping context */
704 462 : if (!IS_UPPER_REL(glob_cxt->foreignrel))
705 0 : return false;
706 :
707 : /* Only non-split aggregates are pushable. */
708 462 : if (agg->aggsplit != AGGSPLIT_SIMPLE)
709 0 : return false;
710 :
711 : /* As usual, it must be shippable. */
712 462 : if (!is_shippable(agg->aggfnoid, ProcedureRelationId, fpinfo))
713 8 : return false;
714 :
715 : /*
716 : * Recurse to input args. aggdirectargs, aggorder and
717 : * aggdistinct are all present in args, so no need to check
718 : * their shippability explicitly.
719 : */
720 832 : foreach(lc, agg->args)
721 : {
722 402 : Node *n = (Node *) lfirst(lc);
723 :
724 : /* If TargetEntry, extract the expression from it */
725 402 : if (IsA(n, TargetEntry))
726 : {
727 402 : TargetEntry *tle = (TargetEntry *) n;
728 :
729 402 : n = (Node *) tle->expr;
730 : }
731 :
732 402 : if (!foreign_expr_walker(n, glob_cxt, &inner_cxt))
733 24 : return false;
734 : }
735 :
736 : /*
737 : * For aggorder elements, check whether the sort operator, if
738 : * specified, is shippable or not.
739 : */
740 430 : if (agg->aggorder)
741 : {
742 : ListCell *lc;
743 :
744 116 : foreach(lc, agg->aggorder)
745 : {
746 64 : SortGroupClause *srt = (SortGroupClause *) lfirst(lc);
747 : Oid sortcoltype;
748 : TypeCacheEntry *typentry;
749 : TargetEntry *tle;
750 :
751 64 : tle = get_sortgroupref_tle(srt->tleSortGroupRef,
752 : agg->args);
753 64 : sortcoltype = exprType((Node *) tle->expr);
754 64 : typentry = lookup_type_cache(sortcoltype,
755 : TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
756 : /* Check shippability of non-default sort operator. */
757 64 : if (srt->sortop != typentry->lt_opr &&
758 24 : srt->sortop != typentry->gt_opr &&
759 12 : !is_shippable(srt->sortop, OperatorRelationId,
760 : fpinfo))
761 8 : return false;
762 : }
763 : }
764 :
765 : /* Check aggregate filter */
766 422 : if (!foreign_expr_walker((Node *) agg->aggfilter,
767 : glob_cxt, &inner_cxt))
768 4 : return false;
769 :
770 : /*
771 : * If aggregate's input collation is not derived from a
772 : * foreign Var, it can't be sent to remote.
773 : */
774 418 : if (agg->inputcollid == InvalidOid)
775 : /* OK, inputs are all noncollatable */ ;
776 36 : else if (inner_cxt.state != FDW_COLLATE_SAFE ||
777 36 : agg->inputcollid != inner_cxt.collation)
778 0 : return false;
779 :
780 : /*
781 : * Detect whether node is introducing a collation not derived
782 : * from a foreign Var. (If so, we just mark it unsafe for now
783 : * rather than immediately returning false, since the parent
784 : * node might not care.)
785 : */
786 418 : collation = agg->aggcollid;
787 418 : if (collation == InvalidOid)
788 416 : state = FDW_COLLATE_NONE;
789 2 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
790 2 : collation == inner_cxt.collation)
791 2 : state = FDW_COLLATE_SAFE;
792 0 : else if (collation == DEFAULT_COLLATION_OID)
793 0 : state = FDW_COLLATE_NONE;
794 : else
795 0 : state = FDW_COLLATE_UNSAFE;
796 : }
797 418 : break;
798 60 : default:
799 :
800 : /*
801 : * If it's anything else, assume it's unsafe. This list can be
802 : * expanded later, but don't forget to add deparse support below.
803 : */
804 60 : return false;
805 : }
806 :
807 : /*
808 : * If result type of given expression is not shippable, it can't be sent
809 : * to remote because it might have incompatible semantics on remote side.
810 : */
811 11886 : if (check_type && !is_shippable(exprType(node), TypeRelationId, fpinfo))
812 50 : return false;
813 :
814 : /*
815 : * Now, merge my collation information into my parent's state.
816 : */
817 11836 : if (state > outer_cxt->state)
818 : {
819 : /* Override previous parent state */
820 574 : outer_cxt->collation = collation;
821 574 : outer_cxt->state = state;
822 : }
823 11262 : else if (state == outer_cxt->state)
824 : {
825 : /* Merge, or detect error if there's a collation conflict */
826 11186 : switch (state)
827 : {
828 11180 : case FDW_COLLATE_NONE:
829 : /* Nothing + nothing is still nothing */
830 11180 : break;
831 4 : case FDW_COLLATE_SAFE:
832 4 : if (collation != outer_cxt->collation)
833 : {
834 : /*
835 : * Non-default collation always beats default.
836 : */
837 0 : if (outer_cxt->collation == DEFAULT_COLLATION_OID)
838 : {
839 : /* Override previous parent state */
840 0 : outer_cxt->collation = collation;
841 : }
842 0 : else if (collation != DEFAULT_COLLATION_OID)
843 : {
844 : /*
845 : * Conflict; show state as indeterminate. We don't
846 : * want to "return false" right away, since parent
847 : * node might not care about collation.
848 : */
849 0 : outer_cxt->state = FDW_COLLATE_UNSAFE;
850 : }
851 : }
852 4 : break;
853 2 : case FDW_COLLATE_UNSAFE:
854 : /* We're still conflicted ... */
855 2 : break;
856 : }
857 76 : }
858 :
859 : /* It looks OK */
860 11836 : return true;
861 : }
862 :
863 : /*
864 : * Returns true if given expr is something we'd have to send the value of
865 : * to the foreign server.
866 : *
867 : * This should return true when the expression is a shippable node that
868 : * deparseExpr would add to context->params_list. Note that we don't care
869 : * if the expression *contains* such a node, only whether one appears at top
870 : * level. We need this to detect cases where setrefs.c would recognize a
871 : * false match between an fdw_exprs item (which came from the params_list)
872 : * and an entry in fdw_scan_tlist (which we're considering putting the given
873 : * expression into).
874 : */
875 : bool
876 506 : is_foreign_param(PlannerInfo *root,
877 : RelOptInfo *baserel,
878 : Expr *expr)
879 : {
880 506 : if (expr == NULL)
881 0 : return false;
882 :
883 506 : switch (nodeTag(expr))
884 : {
885 152 : case T_Var:
886 : {
887 : /* It would have to be sent unless it's a foreign Var */
888 152 : Var *var = (Var *) expr;
889 152 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) (baserel->fdw_private);
890 : Relids relids;
891 :
892 152 : if (IS_UPPER_REL(baserel))
893 152 : relids = fpinfo->outerrel->relids;
894 : else
895 0 : relids = baserel->relids;
896 :
897 152 : if (bms_is_member(var->varno, relids) && var->varlevelsup == 0)
898 152 : return false; /* foreign Var, so not a param */
899 : else
900 0 : return true; /* it'd have to be a param */
901 : break;
902 : }
903 8 : case T_Param:
904 : /* Params always have to be sent to the foreign server */
905 8 : return true;
906 346 : default:
907 346 : break;
908 : }
909 346 : return false;
910 : }
911 :
912 : /*
913 : * Convert type OID + typmod info into a type name we can ship to the remote
914 : * server. Someplace else had better have verified that this type name is
915 : * expected to be known on the remote end.
916 : *
917 : * This is almost just format_type_with_typemod(), except that if left to its
918 : * own devices, that function will make schema-qualification decisions based
919 : * on the local search_path, which is wrong. We must schema-qualify all
920 : * type names that are not in pg_catalog. We assume here that built-in types
921 : * are all in pg_catalog and need not be qualified; otherwise, qualify.
922 : */
923 : static char *
924 862 : deparse_type_name(Oid type_oid, int32 typemod)
925 : {
926 862 : bits16 flags = FORMAT_TYPE_TYPEMOD_GIVEN;
927 :
928 862 : if (!is_builtin(type_oid))
929 0 : flags |= FORMAT_TYPE_FORCE_QUALIFY;
930 :
931 862 : return format_type_extended(type_oid, typemod, flags);
932 : }
933 :
934 : /*
935 : * Build the targetlist for given relation to be deparsed as SELECT clause.
936 : *
937 : * The output targetlist contains the columns that need to be fetched from the
938 : * foreign server for the given relation. If foreignrel is an upper relation,
939 : * then the output targetlist can also contain expressions to be evaluated on
940 : * foreign server.
941 : */
942 : List *
943 1038 : build_tlist_to_deparse(RelOptInfo *foreignrel)
944 : {
945 1038 : List *tlist = NIL;
946 1038 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
947 : ListCell *lc;
948 :
949 : /*
950 : * For an upper relation, we have already built the target list while
951 : * checking shippability, so just return that.
952 : */
953 1038 : if (IS_UPPER_REL(foreignrel))
954 284 : return fpinfo->grouped_tlist;
955 :
956 : /*
957 : * We require columns specified in foreignrel->reltarget->exprs and those
958 : * required for evaluating the local conditions.
959 : */
960 754 : tlist = add_to_flat_tlist(tlist,
961 754 : pull_var_clause((Node *) foreignrel->reltarget->exprs,
962 : PVC_RECURSE_PLACEHOLDERS));
963 790 : foreach(lc, fpinfo->local_conds)
964 : {
965 36 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
966 :
967 36 : tlist = add_to_flat_tlist(tlist,
968 36 : pull_var_clause((Node *) rinfo->clause,
969 : PVC_RECURSE_PLACEHOLDERS));
970 : }
971 :
972 754 : return tlist;
973 : }
974 :
975 : /*
976 : * Deparse SELECT statement for given relation into buf.
977 : *
978 : * tlist contains the list of desired columns to be fetched from foreign server.
979 : * For a base relation fpinfo->attrs_used is used to construct SELECT clause,
980 : * hence the tlist is ignored for a base relation.
981 : *
982 : * remote_conds is the list of conditions to be deparsed into the WHERE clause
983 : * (or, in the case of upper relations, into the HAVING clause).
984 : *
985 : * If params_list is not NULL, it receives a list of Params and other-relation
986 : * Vars used in the clauses; these values must be transmitted to the remote
987 : * server as parameter values.
988 : *
989 : * If params_list is NULL, we're generating the query for EXPLAIN purposes,
990 : * so Params and other-relation Vars should be replaced by dummy values.
991 : *
992 : * pathkeys is the list of pathkeys to order the result by.
993 : *
994 : * is_subquery is the flag to indicate whether to deparse the specified
995 : * relation as a subquery.
996 : *
997 : * List of columns selected is returned in retrieved_attrs.
998 : */
999 : void
1000 3200 : deparseSelectStmtForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *rel,
1001 : List *tlist, List *remote_conds, List *pathkeys,
1002 : bool has_final_sort, bool has_limit, bool is_subquery,
1003 : List **retrieved_attrs, List **params_list)
1004 : {
1005 : deparse_expr_cxt context;
1006 3200 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private;
1007 : List *quals;
1008 :
1009 : /*
1010 : * We handle relations for foreign tables, joins between those and upper
1011 : * relations.
1012 : */
1013 : Assert(IS_JOIN_REL(rel) || IS_SIMPLE_REL(rel) || IS_UPPER_REL(rel));
1014 :
1015 : /* Fill portions of context common to upper, join and base relation */
1016 3200 : context.buf = buf;
1017 3200 : context.root = root;
1018 3200 : context.foreignrel = rel;
1019 3200 : context.scanrel = IS_UPPER_REL(rel) ? fpinfo->outerrel : rel;
1020 3200 : context.params_list = params_list;
1021 :
1022 : /* Construct SELECT clause */
1023 3200 : deparseSelectSql(tlist, is_subquery, retrieved_attrs, &context);
1024 :
1025 : /*
1026 : * For upper relations, the WHERE clause is built from the remote
1027 : * conditions of the underlying scan relation; otherwise, we can use the
1028 : * supplied list of remote conditions directly.
1029 : */
1030 3200 : if (IS_UPPER_REL(rel))
1031 284 : {
1032 : PgFdwRelationInfo *ofpinfo;
1033 :
1034 284 : ofpinfo = (PgFdwRelationInfo *) fpinfo->outerrel->fdw_private;
1035 284 : quals = ofpinfo->remote_conds;
1036 : }
1037 : else
1038 2916 : quals = remote_conds;
1039 :
1040 : /* Construct FROM and WHERE clauses */
1041 3200 : deparseFromExpr(quals, &context);
1042 :
1043 3200 : if (IS_UPPER_REL(rel))
1044 : {
1045 : /* Append GROUP BY clause */
1046 284 : appendGroupByClause(tlist, &context);
1047 :
1048 : /* Append HAVING clause */
1049 284 : if (remote_conds)
1050 : {
1051 36 : appendStringInfoString(buf, " HAVING ");
1052 36 : appendConditions(remote_conds, &context);
1053 : }
1054 : }
1055 :
1056 : /* Add ORDER BY clause if we found any useful pathkeys */
1057 3200 : if (pathkeys)
1058 922 : appendOrderByClause(pathkeys, has_final_sort, &context);
1059 :
1060 : /* Add LIMIT clause if necessary */
1061 3200 : if (has_limit)
1062 204 : appendLimitClause(&context);
1063 :
1064 : /* Add any necessary FOR UPDATE/SHARE. */
1065 3200 : deparseLockingClause(&context);
1066 3200 : }
1067 :
1068 : /*
1069 : * Construct a simple SELECT statement that retrieves desired columns
1070 : * of the specified foreign table, and append it to "buf". The output
1071 : * contains just "SELECT ... ".
1072 : *
1073 : * We also create an integer List of the columns being retrieved, which is
1074 : * returned to *retrieved_attrs, unless we deparse the specified relation
1075 : * as a subquery.
1076 : *
1077 : * tlist is the list of desired columns. is_subquery is the flag to
1078 : * indicate whether to deparse the specified relation as a subquery.
1079 : * Read prologue of deparseSelectStmtForRel() for details.
1080 : */
1081 : static void
1082 3200 : deparseSelectSql(List *tlist, bool is_subquery, List **retrieved_attrs,
1083 : deparse_expr_cxt *context)
1084 : {
1085 3200 : StringInfo buf = context->buf;
1086 3200 : RelOptInfo *foreignrel = context->foreignrel;
1087 3200 : PlannerInfo *root = context->root;
1088 3200 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
1089 :
1090 : /*
1091 : * Construct SELECT list
1092 : */
1093 3200 : appendStringInfoString(buf, "SELECT ");
1094 :
1095 3200 : if (is_subquery)
1096 : {
1097 : /*
1098 : * For a relation that is deparsed as a subquery, emit expressions
1099 : * specified in the relation's reltarget. Note that since this is for
1100 : * the subquery, no need to care about *retrieved_attrs.
1101 : */
1102 56 : deparseSubqueryTargetList(context);
1103 : }
1104 3144 : else if (IS_JOIN_REL(foreignrel) || IS_UPPER_REL(foreignrel))
1105 : {
1106 : /*
1107 : * For a join or upper relation the input tlist gives the list of
1108 : * columns required to be fetched from the foreign server.
1109 : */
1110 1038 : deparseExplicitTargetList(tlist, false, retrieved_attrs, context);
1111 : }
1112 : else
1113 : {
1114 : /*
1115 : * For a base relation fpinfo->attrs_used gives the list of columns
1116 : * required to be fetched from the foreign server.
1117 : */
1118 2106 : RangeTblEntry *rte = planner_rt_fetch(foreignrel->relid, root);
1119 :
1120 : /*
1121 : * Core code already has some lock on each rel being planned, so we
1122 : * can use NoLock here.
1123 : */
1124 2106 : Relation rel = table_open(rte->relid, NoLock);
1125 :
1126 2106 : deparseTargetList(buf, rte, foreignrel->relid, rel, false,
1127 : fpinfo->attrs_used, false, retrieved_attrs);
1128 2106 : table_close(rel, NoLock);
1129 : }
1130 3200 : }
1131 :
1132 : /*
1133 : * Construct a FROM clause and, if needed, a WHERE clause, and append those to
1134 : * "buf".
1135 : *
1136 : * quals is the list of clauses to be included in the WHERE clause.
1137 : * (These may or may not include RestrictInfo decoration.)
1138 : */
1139 : static void
1140 3200 : deparseFromExpr(List *quals, deparse_expr_cxt *context)
1141 : {
1142 3200 : StringInfo buf = context->buf;
1143 3200 : RelOptInfo *scanrel = context->scanrel;
1144 :
1145 : /* For upper relations, scanrel must be either a joinrel or a baserel */
1146 : Assert(!IS_UPPER_REL(context->foreignrel) ||
1147 : IS_JOIN_REL(scanrel) || IS_SIMPLE_REL(scanrel));
1148 :
1149 : /* Construct FROM clause */
1150 3200 : appendStringInfoString(buf, " FROM ");
1151 3200 : deparseFromExprForRel(buf, context->root, scanrel,
1152 3200 : (bms_membership(scanrel->relids) == BMS_MULTIPLE),
1153 : (Index) 0, NULL, context->params_list);
1154 :
1155 : /* Construct WHERE clause */
1156 3200 : if (quals != NIL)
1157 : {
1158 1258 : appendStringInfoString(buf, " WHERE ");
1159 1258 : appendConditions(quals, context);
1160 : }
1161 3200 : }
1162 :
1163 : /*
1164 : * Emit a target list that retrieves the columns specified in attrs_used.
1165 : * This is used for both SELECT and RETURNING targetlists; the is_returning
1166 : * parameter is true only for a RETURNING targetlist.
1167 : *
1168 : * The tlist text is appended to buf, and we also create an integer List
1169 : * of the columns being retrieved, which is returned to *retrieved_attrs.
1170 : *
1171 : * If qualify_col is true, add relation alias before the column name.
1172 : */
1173 : static void
1174 2688 : deparseTargetList(StringInfo buf,
1175 : RangeTblEntry *rte,
1176 : Index rtindex,
1177 : Relation rel,
1178 : bool is_returning,
1179 : Bitmapset *attrs_used,
1180 : bool qualify_col,
1181 : List **retrieved_attrs)
1182 : {
1183 2688 : TupleDesc tupdesc = RelationGetDescr(rel);
1184 : bool have_wholerow;
1185 : bool first;
1186 : int i;
1187 :
1188 2688 : *retrieved_attrs = NIL;
1189 :
1190 : /* If there's a whole-row reference, we'll need all the columns. */
1191 2688 : have_wholerow = bms_is_member(0 - FirstLowInvalidHeapAttributeNumber,
1192 : attrs_used);
1193 :
1194 2688 : first = true;
1195 19564 : for (i = 1; i <= tupdesc->natts; i++)
1196 : {
1197 16876 : Form_pg_attribute attr = TupleDescAttr(tupdesc, i - 1);
1198 :
1199 : /* Ignore dropped attributes. */
1200 16876 : if (attr->attisdropped)
1201 1528 : continue;
1202 :
1203 26820 : if (have_wholerow ||
1204 11472 : bms_is_member(i - FirstLowInvalidHeapAttributeNumber,
1205 : attrs_used))
1206 : {
1207 8878 : if (!first)
1208 6318 : appendStringInfoString(buf, ", ");
1209 2560 : else if (is_returning)
1210 178 : appendStringInfoString(buf, " RETURNING ");
1211 8878 : first = false;
1212 :
1213 8878 : deparseColumnRef(buf, rtindex, i, rte, qualify_col);
1214 :
1215 8878 : *retrieved_attrs = lappend_int(*retrieved_attrs, i);
1216 : }
1217 : }
1218 :
1219 : /*
1220 : * Add ctid if needed. We currently don't support retrieving any other
1221 : * system columns.
1222 : */
1223 2688 : if (bms_is_member(SelfItemPointerAttributeNumber - FirstLowInvalidHeapAttributeNumber,
1224 : attrs_used))
1225 : {
1226 470 : if (!first)
1227 382 : appendStringInfoString(buf, ", ");
1228 88 : else if (is_returning)
1229 0 : appendStringInfoString(buf, " RETURNING ");
1230 470 : first = false;
1231 :
1232 470 : if (qualify_col)
1233 0 : ADD_REL_QUALIFIER(buf, rtindex);
1234 470 : appendStringInfoString(buf, "ctid");
1235 :
1236 470 : *retrieved_attrs = lappend_int(*retrieved_attrs,
1237 : SelfItemPointerAttributeNumber);
1238 : }
1239 :
1240 : /* Don't generate bad syntax if no undropped columns */
1241 2688 : if (first && !is_returning)
1242 28 : appendStringInfoString(buf, "NULL");
1243 2688 : }
1244 :
1245 : /*
1246 : * Deparse the appropriate locking clause (FOR UPDATE or FOR SHARE) for a
1247 : * given relation (context->scanrel).
1248 : */
1249 : static void
1250 3200 : deparseLockingClause(deparse_expr_cxt *context)
1251 : {
1252 3200 : StringInfo buf = context->buf;
1253 3200 : PlannerInfo *root = context->root;
1254 3200 : RelOptInfo *rel = context->scanrel;
1255 3200 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private;
1256 3200 : int relid = -1;
1257 :
1258 7382 : while ((relid = bms_next_member(rel->relids, relid)) >= 0)
1259 : {
1260 : /*
1261 : * Ignore relation if it appears in a lower subquery. Locking clause
1262 : * for such a relation is included in the subquery if necessary.
1263 : */
1264 4182 : if (bms_is_member(relid, fpinfo->lower_subquery_rels))
1265 64 : continue;
1266 :
1267 : /*
1268 : * Add FOR UPDATE/SHARE if appropriate. We apply locking during the
1269 : * initial row fetch, rather than later on as is done for local
1270 : * tables. The extra roundtrips involved in trying to duplicate the
1271 : * local semantics exactly don't seem worthwhile (see also comments
1272 : * for RowMarkType).
1273 : *
1274 : * Note: because we actually run the query as a cursor, this assumes
1275 : * that DECLARE CURSOR ... FOR UPDATE is supported, which it isn't
1276 : * before 8.3.
1277 : */
1278 4118 : if (relid == root->parse->resultRelation &&
1279 472 : (root->parse->commandType == CMD_UPDATE ||
1280 196 : root->parse->commandType == CMD_DELETE))
1281 : {
1282 : /* Relation is UPDATE/DELETE target, so use FOR UPDATE */
1283 472 : appendStringInfoString(buf, " FOR UPDATE");
1284 :
1285 : /* Add the relation alias if we are here for a join relation */
1286 556 : if (IS_JOIN_REL(rel))
1287 84 : appendStringInfo(buf, " OF %s%d", REL_ALIAS_PREFIX, relid);
1288 : }
1289 : else
1290 : {
1291 3646 : PlanRowMark *rc = get_plan_rowmark(root->rowMarks, relid);
1292 :
1293 3646 : if (rc)
1294 : {
1295 : /*
1296 : * Relation is specified as a FOR UPDATE/SHARE target, so
1297 : * handle that. (But we could also see LCS_NONE, meaning this
1298 : * isn't a target relation after all.)
1299 : *
1300 : * For now, just ignore any [NO] KEY specification, since (a)
1301 : * it's not clear what that means for a remote table that we
1302 : * don't have complete information about, and (b) it wouldn't
1303 : * work anyway on older remote servers. Likewise, we don't
1304 : * worry about NOWAIT.
1305 : */
1306 588 : switch (rc->strength)
1307 : {
1308 292 : case LCS_NONE:
1309 : /* No locking needed */
1310 292 : break;
1311 68 : case LCS_FORKEYSHARE:
1312 : case LCS_FORSHARE:
1313 68 : appendStringInfoString(buf, " FOR SHARE");
1314 68 : break;
1315 228 : case LCS_FORNOKEYUPDATE:
1316 : case LCS_FORUPDATE:
1317 228 : appendStringInfoString(buf, " FOR UPDATE");
1318 228 : break;
1319 : }
1320 :
1321 : /* Add the relation alias if we are here for a join relation */
1322 588 : if (bms_membership(rel->relids) == BMS_MULTIPLE &&
1323 356 : rc->strength != LCS_NONE)
1324 208 : appendStringInfo(buf, " OF %s%d", REL_ALIAS_PREFIX, relid);
1325 : }
1326 : }
1327 : }
1328 3200 : }
1329 :
1330 : /*
1331 : * Deparse conditions from the provided list and append them to buf.
1332 : *
1333 : * The conditions in the list are assumed to be ANDed. This function is used to
1334 : * deparse WHERE clauses, JOIN .. ON clauses and HAVING clauses.
1335 : *
1336 : * Depending on the caller, the list elements might be either RestrictInfos
1337 : * or bare clauses.
1338 : */
1339 : static void
1340 2326 : appendConditions(List *exprs, deparse_expr_cxt *context)
1341 : {
1342 : int nestlevel;
1343 : ListCell *lc;
1344 2326 : bool is_first = true;
1345 2326 : StringInfo buf = context->buf;
1346 :
1347 : /* Make sure any constants in the exprs are printed portably */
1348 2326 : nestlevel = set_transmission_modes();
1349 :
1350 5308 : foreach(lc, exprs)
1351 : {
1352 2982 : Expr *expr = (Expr *) lfirst(lc);
1353 :
1354 : /* Extract clause from RestrictInfo, if required */
1355 2982 : if (IsA(expr, RestrictInfo))
1356 2454 : expr = ((RestrictInfo *) expr)->clause;
1357 :
1358 : /* Connect expressions with "AND" and parenthesize each condition. */
1359 2982 : if (!is_first)
1360 656 : appendStringInfoString(buf, " AND ");
1361 :
1362 2982 : appendStringInfoChar(buf, '(');
1363 2982 : deparseExpr(expr, context);
1364 2982 : appendStringInfoChar(buf, ')');
1365 :
1366 2982 : is_first = false;
1367 : }
1368 :
1369 2326 : reset_transmission_modes(nestlevel);
1370 2326 : }
1371 :
1372 : /* Output join name for given join type */
1373 : const char *
1374 1408 : get_jointype_name(JoinType jointype)
1375 : {
1376 1408 : switch (jointype)
1377 : {
1378 828 : case JOIN_INNER:
1379 828 : return "INNER";
1380 :
1381 364 : case JOIN_LEFT:
1382 364 : return "LEFT";
1383 :
1384 0 : case JOIN_RIGHT:
1385 0 : return "RIGHT";
1386 :
1387 216 : case JOIN_FULL:
1388 216 : return "FULL";
1389 :
1390 0 : default:
1391 : /* Shouldn't come here, but protect from buggy code. */
1392 0 : elog(ERROR, "unsupported join type %d", jointype);
1393 : }
1394 :
1395 : /* Keep compiler happy */
1396 : return NULL;
1397 : }
1398 :
1399 : /*
1400 : * Deparse given targetlist and append it to context->buf.
1401 : *
1402 : * tlist is list of TargetEntry's which in turn contain Var nodes.
1403 : *
1404 : * retrieved_attrs is the list of continuously increasing integers starting
1405 : * from 1. It has same number of entries as tlist.
1406 : *
1407 : * This is used for both SELECT and RETURNING targetlists; the is_returning
1408 : * parameter is true only for a RETURNING targetlist.
1409 : */
1410 : static void
1411 1062 : deparseExplicitTargetList(List *tlist,
1412 : bool is_returning,
1413 : List **retrieved_attrs,
1414 : deparse_expr_cxt *context)
1415 : {
1416 : ListCell *lc;
1417 1062 : StringInfo buf = context->buf;
1418 1062 : int i = 0;
1419 :
1420 1062 : *retrieved_attrs = NIL;
1421 :
1422 5188 : foreach(lc, tlist)
1423 : {
1424 4126 : TargetEntry *tle = lfirst_node(TargetEntry, lc);
1425 :
1426 4126 : if (i > 0)
1427 3080 : appendStringInfoString(buf, ", ");
1428 1046 : else if (is_returning)
1429 12 : appendStringInfoString(buf, " RETURNING ");
1430 :
1431 4126 : deparseExpr((Expr *) tle->expr, context);
1432 :
1433 4126 : *retrieved_attrs = lappend_int(*retrieved_attrs, i + 1);
1434 4126 : i++;
1435 : }
1436 :
1437 1062 : if (i == 0 && !is_returning)
1438 4 : appendStringInfoString(buf, "NULL");
1439 1062 : }
1440 :
1441 : /*
1442 : * Emit expressions specified in the given relation's reltarget.
1443 : *
1444 : * This is used for deparsing the given relation as a subquery.
1445 : */
1446 : static void
1447 56 : deparseSubqueryTargetList(deparse_expr_cxt *context)
1448 : {
1449 56 : StringInfo buf = context->buf;
1450 56 : RelOptInfo *foreignrel = context->foreignrel;
1451 : bool first;
1452 : ListCell *lc;
1453 :
1454 : /* Should only be called in these cases. */
1455 : Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
1456 :
1457 56 : first = true;
1458 120 : foreach(lc, foreignrel->reltarget->exprs)
1459 : {
1460 64 : Node *node = (Node *) lfirst(lc);
1461 :
1462 64 : if (!first)
1463 16 : appendStringInfoString(buf, ", ");
1464 64 : first = false;
1465 :
1466 64 : deparseExpr((Expr *) node, context);
1467 : }
1468 :
1469 : /* Don't generate bad syntax if no expressions */
1470 56 : if (first)
1471 8 : appendStringInfoString(buf, "NULL");
1472 56 : }
1473 :
1474 : /*
1475 : * Construct FROM clause for given relation
1476 : *
1477 : * The function constructs ... JOIN ... ON ... for join relation. For a base
1478 : * relation it just returns schema-qualified tablename, with the appropriate
1479 : * alias if so requested.
1480 : *
1481 : * 'ignore_rel' is either zero or the RT index of a target relation. In the
1482 : * latter case the function constructs FROM clause of UPDATE or USING clause
1483 : * of DELETE; it deparses the join relation as if the relation never contained
1484 : * the target relation, and creates a List of conditions to be deparsed into
1485 : * the top-level WHERE clause, which is returned to *ignore_conds.
1486 : */
1487 : static void
1488 5156 : deparseFromExprForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *foreignrel,
1489 : bool use_alias, Index ignore_rel, List **ignore_conds,
1490 : List **params_list)
1491 : {
1492 5156 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
1493 :
1494 5156 : if (IS_JOIN_REL(foreignrel))
1495 982 : {
1496 : StringInfoData join_sql_o;
1497 : StringInfoData join_sql_i;
1498 1006 : RelOptInfo *outerrel = fpinfo->outerrel;
1499 1006 : RelOptInfo *innerrel = fpinfo->innerrel;
1500 1006 : bool outerrel_is_target = false;
1501 1006 : bool innerrel_is_target = false;
1502 :
1503 1006 : if (ignore_rel > 0 && bms_is_member(ignore_rel, foreignrel->relids))
1504 : {
1505 : /*
1506 : * If this is an inner join, add joinclauses to *ignore_conds and
1507 : * set it to empty so that those can be deparsed into the WHERE
1508 : * clause. Note that since the target relation can never be
1509 : * within the nullable side of an outer join, those could safely
1510 : * be pulled up into the WHERE clause (see foreign_join_ok()).
1511 : * Note also that since the target relation is only inner-joined
1512 : * to any other relation in the query, all conditions in the join
1513 : * tree mentioning the target relation could be deparsed into the
1514 : * WHERE clause by doing this recursively.
1515 : */
1516 32 : if (fpinfo->jointype == JOIN_INNER)
1517 : {
1518 56 : *ignore_conds = list_concat(*ignore_conds,
1519 28 : fpinfo->joinclauses);
1520 28 : fpinfo->joinclauses = NIL;
1521 : }
1522 :
1523 : /*
1524 : * Check if either of the input relations is the target relation.
1525 : */
1526 32 : if (outerrel->relid == ignore_rel)
1527 24 : outerrel_is_target = true;
1528 8 : else if (innerrel->relid == ignore_rel)
1529 0 : innerrel_is_target = true;
1530 : }
1531 :
1532 : /* Deparse outer relation if not the target relation. */
1533 1006 : if (!outerrel_is_target)
1534 : {
1535 982 : initStringInfo(&join_sql_o);
1536 982 : deparseRangeTblRef(&join_sql_o, root, outerrel,
1537 982 : fpinfo->make_outerrel_subquery,
1538 : ignore_rel, ignore_conds, params_list);
1539 :
1540 : /*
1541 : * If inner relation is the target relation, skip deparsing it.
1542 : * Note that since the join of the target relation with any other
1543 : * relation in the query is an inner join and can never be within
1544 : * the nullable side of an outer join, the join could be
1545 : * interchanged with higher-level joins (cf. identity 1 on outer
1546 : * join reordering shown in src/backend/optimizer/README), which
1547 : * means it's safe to skip the target-relation deparsing here.
1548 : */
1549 982 : if (innerrel_is_target)
1550 : {
1551 : Assert(fpinfo->jointype == JOIN_INNER);
1552 : Assert(fpinfo->joinclauses == NIL);
1553 0 : appendBinaryStringInfo(buf, join_sql_o.data, join_sql_o.len);
1554 24 : return;
1555 : }
1556 : }
1557 :
1558 : /* Deparse inner relation if not the target relation. */
1559 1006 : if (!innerrel_is_target)
1560 : {
1561 1006 : initStringInfo(&join_sql_i);
1562 1006 : deparseRangeTblRef(&join_sql_i, root, innerrel,
1563 1006 : fpinfo->make_innerrel_subquery,
1564 : ignore_rel, ignore_conds, params_list);
1565 :
1566 : /*
1567 : * If outer relation is the target relation, skip deparsing it.
1568 : * See the above note about safety.
1569 : */
1570 1006 : if (outerrel_is_target)
1571 : {
1572 : Assert(fpinfo->jointype == JOIN_INNER);
1573 : Assert(fpinfo->joinclauses == NIL);
1574 24 : appendBinaryStringInfo(buf, join_sql_i.data, join_sql_i.len);
1575 24 : return;
1576 : }
1577 : }
1578 :
1579 : /* Neither of the relations is the target relation. */
1580 : Assert(!outerrel_is_target && !innerrel_is_target);
1581 :
1582 : /*
1583 : * For a join relation FROM clause entry is deparsed as
1584 : *
1585 : * ((outer relation) <join type> (inner relation) ON (joinclauses))
1586 : */
1587 982 : appendStringInfo(buf, "(%s %s JOIN %s ON ", join_sql_o.data,
1588 : get_jointype_name(fpinfo->jointype), join_sql_i.data);
1589 :
1590 : /* Append join clause; (TRUE) if no join clause */
1591 982 : if (fpinfo->joinclauses)
1592 : {
1593 : deparse_expr_cxt context;
1594 :
1595 950 : context.buf = buf;
1596 950 : context.foreignrel = foreignrel;
1597 950 : context.scanrel = foreignrel;
1598 950 : context.root = root;
1599 950 : context.params_list = params_list;
1600 :
1601 950 : appendStringInfoChar(buf, '(');
1602 950 : appendConditions(fpinfo->joinclauses, &context);
1603 950 : appendStringInfoChar(buf, ')');
1604 : }
1605 : else
1606 32 : appendStringInfoString(buf, "(TRUE)");
1607 :
1608 : /* End the FROM clause entry. */
1609 982 : appendStringInfoChar(buf, ')');
1610 : }
1611 : else
1612 : {
1613 4150 : RangeTblEntry *rte = planner_rt_fetch(foreignrel->relid, root);
1614 :
1615 : /*
1616 : * Core code already has some lock on each rel being planned, so we
1617 : * can use NoLock here.
1618 : */
1619 4150 : Relation rel = table_open(rte->relid, NoLock);
1620 :
1621 4150 : deparseRelation(buf, rel);
1622 :
1623 : /*
1624 : * Add a unique alias to avoid any conflict in relation names due to
1625 : * pulled up subqueries in the query being built for a pushed down
1626 : * join.
1627 : */
1628 4150 : if (use_alias)
1629 1744 : appendStringInfo(buf, " %s%d", REL_ALIAS_PREFIX, foreignrel->relid);
1630 :
1631 4150 : table_close(rel, NoLock);
1632 : }
1633 : }
1634 :
1635 : /*
1636 : * Append FROM clause entry for the given relation into buf.
1637 : */
1638 : static void
1639 1988 : deparseRangeTblRef(StringInfo buf, PlannerInfo *root, RelOptInfo *foreignrel,
1640 : bool make_subquery, Index ignore_rel, List **ignore_conds,
1641 : List **params_list)
1642 : {
1643 1988 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
1644 :
1645 : /* Should only be called in these cases. */
1646 : Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
1647 :
1648 : Assert(fpinfo->local_conds == NIL);
1649 :
1650 : /* If make_subquery is true, deparse the relation as a subquery. */
1651 1988 : if (make_subquery)
1652 : {
1653 : List *retrieved_attrs;
1654 : int ncols;
1655 :
1656 : /*
1657 : * The given relation shouldn't contain the target relation, because
1658 : * this should only happen for input relations for a full join, and
1659 : * such relations can never contain an UPDATE/DELETE target.
1660 : */
1661 : Assert(ignore_rel == 0 ||
1662 : !bms_is_member(ignore_rel, foreignrel->relids));
1663 :
1664 : /* Deparse the subquery representing the relation. */
1665 56 : appendStringInfoChar(buf, '(');
1666 56 : deparseSelectStmtForRel(buf, root, foreignrel, NIL,
1667 : fpinfo->remote_conds, NIL,
1668 : false, false, true,
1669 : &retrieved_attrs, params_list);
1670 56 : appendStringInfoChar(buf, ')');
1671 :
1672 : /* Append the relation alias. */
1673 56 : appendStringInfo(buf, " %s%d", SUBQUERY_REL_ALIAS_PREFIX,
1674 : fpinfo->relation_index);
1675 :
1676 : /*
1677 : * Append the column aliases if needed. Note that the subquery emits
1678 : * expressions specified in the relation's reltarget (see
1679 : * deparseSubqueryTargetList).
1680 : */
1681 56 : ncols = list_length(foreignrel->reltarget->exprs);
1682 56 : if (ncols > 0)
1683 : {
1684 : int i;
1685 :
1686 48 : appendStringInfoChar(buf, '(');
1687 112 : for (i = 1; i <= ncols; i++)
1688 : {
1689 64 : if (i > 1)
1690 16 : appendStringInfoString(buf, ", ");
1691 :
1692 64 : appendStringInfo(buf, "%s%d", SUBQUERY_COL_ALIAS_PREFIX, i);
1693 : }
1694 48 : appendStringInfoChar(buf, ')');
1695 : }
1696 : }
1697 : else
1698 1932 : deparseFromExprForRel(buf, root, foreignrel, true, ignore_rel,
1699 : ignore_conds, params_list);
1700 1988 : }
1701 :
1702 : /*
1703 : * deparse remote INSERT statement
1704 : *
1705 : * The statement text is appended to buf, and we also create an integer List
1706 : * of the columns being retrieved by WITH CHECK OPTION or RETURNING (if any),
1707 : * which is returned to *retrieved_attrs.
1708 : *
1709 : * This also stores end position of the VALUES clause, so that we can rebuild
1710 : * an INSERT for a batch of rows later.
1711 : */
1712 : void
1713 190 : deparseInsertSql(StringInfo buf, RangeTblEntry *rte,
1714 : Index rtindex, Relation rel,
1715 : List *targetAttrs, bool doNothing,
1716 : List *withCheckOptionList, List *returningList,
1717 : List **retrieved_attrs, int *values_end_len)
1718 : {
1719 : AttrNumber pindex;
1720 : bool first;
1721 : ListCell *lc;
1722 :
1723 190 : appendStringInfoString(buf, "INSERT INTO ");
1724 190 : deparseRelation(buf, rel);
1725 :
1726 190 : if (targetAttrs)
1727 : {
1728 190 : appendStringInfoChar(buf, '(');
1729 :
1730 190 : first = true;
1731 766 : foreach(lc, targetAttrs)
1732 : {
1733 576 : int attnum = lfirst_int(lc);
1734 :
1735 576 : if (!first)
1736 386 : appendStringInfoString(buf, ", ");
1737 576 : first = false;
1738 :
1739 576 : deparseColumnRef(buf, rtindex, attnum, rte, false);
1740 : }
1741 :
1742 190 : appendStringInfoString(buf, ") VALUES (");
1743 :
1744 190 : pindex = 1;
1745 190 : first = true;
1746 766 : foreach(lc, targetAttrs)
1747 : {
1748 576 : if (!first)
1749 386 : appendStringInfoString(buf, ", ");
1750 576 : first = false;
1751 :
1752 576 : appendStringInfo(buf, "$%d", pindex);
1753 576 : pindex++;
1754 : }
1755 :
1756 190 : appendStringInfoChar(buf, ')');
1757 : }
1758 : else
1759 0 : appendStringInfoString(buf, " DEFAULT VALUES");
1760 190 : *values_end_len = buf->len;
1761 :
1762 190 : if (doNothing)
1763 6 : appendStringInfoString(buf, " ON CONFLICT DO NOTHING");
1764 :
1765 190 : deparseReturningList(buf, rte, rtindex, rel,
1766 190 : rel->trigdesc && rel->trigdesc->trig_insert_after_row,
1767 : withCheckOptionList, returningList, retrieved_attrs);
1768 190 : }
1769 :
1770 : /*
1771 : * rebuild remote INSERT statement
1772 : *
1773 : * Provided a number of rows in a batch, builds INSERT statement with the
1774 : * right number of parameters.
1775 : */
1776 : void
1777 12 : rebuildInsertSql(StringInfo buf, char *orig_query,
1778 : int values_end_len, int num_cols,
1779 : int num_rows)
1780 : {
1781 : int i, j;
1782 : int pindex;
1783 : bool first;
1784 :
1785 : /* Make sure the values_end_len is sensible */
1786 : Assert((values_end_len > 0) && (values_end_len <= strlen(orig_query)));
1787 :
1788 : /* Copy up to the end of the first record from the original query */
1789 12 : appendBinaryStringInfo(buf, orig_query, values_end_len);
1790 :
1791 : /*
1792 : * Add records to VALUES clause (we already have parameters for the
1793 : * first row, so start at the right offset).
1794 : */
1795 12 : pindex = num_cols + 1;
1796 74 : for (i = 0; i < num_rows; i++)
1797 : {
1798 62 : appendStringInfoString(buf, ", (");
1799 :
1800 62 : first = true;
1801 124 : for (j = 0; j < num_cols; j++)
1802 : {
1803 62 : if (!first)
1804 0 : appendStringInfoString(buf, ", ");
1805 62 : first = false;
1806 :
1807 62 : appendStringInfo(buf, "$%d", pindex);
1808 62 : pindex++;
1809 : }
1810 :
1811 62 : appendStringInfoChar(buf, ')');
1812 : }
1813 :
1814 : /* Copy stuff after VALUES clause from the original query */
1815 12 : appendStringInfoString(buf, orig_query + values_end_len);
1816 12 : }
1817 :
1818 : /*
1819 : * deparse remote UPDATE statement
1820 : *
1821 : * The statement text is appended to buf, and we also create an integer List
1822 : * of the columns being retrieved by WITH CHECK OPTION or RETURNING (if any),
1823 : * which is returned to *retrieved_attrs.
1824 : */
1825 : void
1826 86 : deparseUpdateSql(StringInfo buf, RangeTblEntry *rte,
1827 : Index rtindex, Relation rel,
1828 : List *targetAttrs,
1829 : List *withCheckOptionList, List *returningList,
1830 : List **retrieved_attrs)
1831 : {
1832 : AttrNumber pindex;
1833 : bool first;
1834 : ListCell *lc;
1835 :
1836 86 : appendStringInfoString(buf, "UPDATE ");
1837 86 : deparseRelation(buf, rel);
1838 86 : appendStringInfoString(buf, " SET ");
1839 :
1840 86 : pindex = 2; /* ctid is always the first param */
1841 86 : first = true;
1842 212 : foreach(lc, targetAttrs)
1843 : {
1844 126 : int attnum = lfirst_int(lc);
1845 :
1846 126 : if (!first)
1847 40 : appendStringInfoString(buf, ", ");
1848 126 : first = false;
1849 :
1850 126 : deparseColumnRef(buf, rtindex, attnum, rte, false);
1851 126 : appendStringInfo(buf, " = $%d", pindex);
1852 126 : pindex++;
1853 : }
1854 86 : appendStringInfoString(buf, " WHERE ctid = $1");
1855 :
1856 86 : deparseReturningList(buf, rte, rtindex, rel,
1857 86 : rel->trigdesc && rel->trigdesc->trig_update_after_row,
1858 : withCheckOptionList, returningList, retrieved_attrs);
1859 86 : }
1860 :
1861 : /*
1862 : * deparse remote UPDATE statement
1863 : *
1864 : * 'buf' is the output buffer to append the statement to
1865 : * 'rtindex' is the RT index of the associated target relation
1866 : * 'rel' is the relation descriptor for the target relation
1867 : * 'foreignrel' is the RelOptInfo for the target relation or the join relation
1868 : * containing all base relations in the query
1869 : * 'targetlist' is the tlist of the underlying foreign-scan plan node
1870 : * 'targetAttrs' is the target columns of the UPDATE
1871 : * 'remote_conds' is the qual clauses that must be evaluated remotely
1872 : * '*params_list' is an output list of exprs that will become remote Params
1873 : * 'returningList' is the RETURNING targetlist
1874 : * '*retrieved_attrs' is an output list of integers of columns being retrieved
1875 : * by RETURNING (if any)
1876 : */
1877 : void
1878 82 : deparseDirectUpdateSql(StringInfo buf, PlannerInfo *root,
1879 : Index rtindex, Relation rel,
1880 : RelOptInfo *foreignrel,
1881 : List *targetlist,
1882 : List *targetAttrs,
1883 : List *remote_conds,
1884 : List **params_list,
1885 : List *returningList,
1886 : List **retrieved_attrs)
1887 : {
1888 : deparse_expr_cxt context;
1889 : int nestlevel;
1890 : bool first;
1891 : ListCell *lc;
1892 82 : RangeTblEntry *rte = planner_rt_fetch(rtindex, root);
1893 :
1894 : /* Set up context struct for recursion */
1895 82 : context.root = root;
1896 82 : context.foreignrel = foreignrel;
1897 82 : context.scanrel = foreignrel;
1898 82 : context.buf = buf;
1899 82 : context.params_list = params_list;
1900 :
1901 82 : appendStringInfoString(buf, "UPDATE ");
1902 82 : deparseRelation(buf, rel);
1903 82 : if (foreignrel->reloptkind == RELOPT_JOINREL)
1904 12 : appendStringInfo(buf, " %s%d", REL_ALIAS_PREFIX, rtindex);
1905 82 : appendStringInfoString(buf, " SET ");
1906 :
1907 : /* Make sure any constants in the exprs are printed portably */
1908 82 : nestlevel = set_transmission_modes();
1909 :
1910 82 : first = true;
1911 180 : foreach(lc, targetAttrs)
1912 : {
1913 98 : int attnum = lfirst_int(lc);
1914 98 : TargetEntry *tle = get_tle_by_resno(targetlist, attnum);
1915 :
1916 98 : if (!tle)
1917 0 : elog(ERROR, "attribute number %d not found in UPDATE targetlist",
1918 : attnum);
1919 :
1920 98 : if (!first)
1921 16 : appendStringInfoString(buf, ", ");
1922 98 : first = false;
1923 :
1924 98 : deparseColumnRef(buf, rtindex, attnum, rte, false);
1925 98 : appendStringInfoString(buf, " = ");
1926 98 : deparseExpr((Expr *) tle->expr, &context);
1927 : }
1928 :
1929 82 : reset_transmission_modes(nestlevel);
1930 :
1931 82 : if (foreignrel->reloptkind == RELOPT_JOINREL)
1932 : {
1933 12 : List *ignore_conds = NIL;
1934 :
1935 12 : appendStringInfoString(buf, " FROM ");
1936 12 : deparseFromExprForRel(buf, root, foreignrel, true, rtindex,
1937 : &ignore_conds, params_list);
1938 12 : remote_conds = list_concat(remote_conds, ignore_conds);
1939 : }
1940 :
1941 82 : if (remote_conds)
1942 : {
1943 54 : appendStringInfoString(buf, " WHERE ");
1944 54 : appendConditions(remote_conds, &context);
1945 : }
1946 :
1947 82 : if (foreignrel->reloptkind == RELOPT_JOINREL)
1948 12 : deparseExplicitTargetList(returningList, true, retrieved_attrs,
1949 : &context);
1950 : else
1951 70 : deparseReturningList(buf, rte, rtindex, rel, false,
1952 : NIL, returningList, retrieved_attrs);
1953 82 : }
1954 :
1955 : /*
1956 : * deparse remote DELETE statement
1957 : *
1958 : * The statement text is appended to buf, and we also create an integer List
1959 : * of the columns being retrieved by RETURNING (if any), which is returned
1960 : * to *retrieved_attrs.
1961 : */
1962 : void
1963 20 : deparseDeleteSql(StringInfo buf, RangeTblEntry *rte,
1964 : Index rtindex, Relation rel,
1965 : List *returningList,
1966 : List **retrieved_attrs)
1967 : {
1968 20 : appendStringInfoString(buf, "DELETE FROM ");
1969 20 : deparseRelation(buf, rel);
1970 20 : appendStringInfoString(buf, " WHERE ctid = $1");
1971 :
1972 20 : deparseReturningList(buf, rte, rtindex, rel,
1973 20 : rel->trigdesc && rel->trigdesc->trig_delete_after_row,
1974 : NIL, returningList, retrieved_attrs);
1975 20 : }
1976 :
1977 : /*
1978 : * deparse remote DELETE statement
1979 : *
1980 : * 'buf' is the output buffer to append the statement to
1981 : * 'rtindex' is the RT index of the associated target relation
1982 : * 'rel' is the relation descriptor for the target relation
1983 : * 'foreignrel' is the RelOptInfo for the target relation or the join relation
1984 : * containing all base relations in the query
1985 : * 'remote_conds' is the qual clauses that must be evaluated remotely
1986 : * '*params_list' is an output list of exprs that will become remote Params
1987 : * 'returningList' is the RETURNING targetlist
1988 : * '*retrieved_attrs' is an output list of integers of columns being retrieved
1989 : * by RETURNING (if any)
1990 : */
1991 : void
1992 84 : deparseDirectDeleteSql(StringInfo buf, PlannerInfo *root,
1993 : Index rtindex, Relation rel,
1994 : RelOptInfo *foreignrel,
1995 : List *remote_conds,
1996 : List **params_list,
1997 : List *returningList,
1998 : List **retrieved_attrs)
1999 : {
2000 : deparse_expr_cxt context;
2001 :
2002 : /* Set up context struct for recursion */
2003 84 : context.root = root;
2004 84 : context.foreignrel = foreignrel;
2005 84 : context.scanrel = foreignrel;
2006 84 : context.buf = buf;
2007 84 : context.params_list = params_list;
2008 :
2009 84 : appendStringInfoString(buf, "DELETE FROM ");
2010 84 : deparseRelation(buf, rel);
2011 84 : if (foreignrel->reloptkind == RELOPT_JOINREL)
2012 12 : appendStringInfo(buf, " %s%d", REL_ALIAS_PREFIX, rtindex);
2013 :
2014 84 : if (foreignrel->reloptkind == RELOPT_JOINREL)
2015 : {
2016 12 : List *ignore_conds = NIL;
2017 :
2018 12 : appendStringInfoString(buf, " USING ");
2019 12 : deparseFromExprForRel(buf, root, foreignrel, true, rtindex,
2020 : &ignore_conds, params_list);
2021 12 : remote_conds = list_concat(remote_conds, ignore_conds);
2022 : }
2023 :
2024 84 : if (remote_conds)
2025 : {
2026 28 : appendStringInfoString(buf, " WHERE ");
2027 28 : appendConditions(remote_conds, &context);
2028 : }
2029 :
2030 84 : if (foreignrel->reloptkind == RELOPT_JOINREL)
2031 12 : deparseExplicitTargetList(returningList, true, retrieved_attrs,
2032 : &context);
2033 : else
2034 72 : deparseReturningList(buf, planner_rt_fetch(rtindex, root),
2035 : rtindex, rel, false,
2036 : NIL, returningList, retrieved_attrs);
2037 84 : }
2038 :
2039 : /*
2040 : * Add a RETURNING clause, if needed, to an INSERT/UPDATE/DELETE.
2041 : */
2042 : static void
2043 438 : deparseReturningList(StringInfo buf, RangeTblEntry *rte,
2044 : Index rtindex, Relation rel,
2045 : bool trig_after_row,
2046 : List *withCheckOptionList,
2047 : List *returningList,
2048 : List **retrieved_attrs)
2049 : {
2050 438 : Bitmapset *attrs_used = NULL;
2051 :
2052 438 : if (trig_after_row)
2053 : {
2054 : /* whole-row reference acquires all non-system columns */
2055 48 : attrs_used =
2056 48 : bms_make_singleton(0 - FirstLowInvalidHeapAttributeNumber);
2057 : }
2058 :
2059 438 : if (withCheckOptionList != NIL)
2060 : {
2061 : /*
2062 : * We need the attrs, non-system and system, mentioned in the local
2063 : * query's WITH CHECK OPTION list.
2064 : *
2065 : * Note: we do this to ensure that WCO constraints will be evaluated
2066 : * on the data actually inserted/updated on the remote side, which
2067 : * might differ from the data supplied by the core code, for example
2068 : * as a result of remote triggers.
2069 : */
2070 28 : pull_varattnos((Node *) withCheckOptionList, rtindex,
2071 : &attrs_used);
2072 : }
2073 :
2074 438 : if (returningList != NIL)
2075 : {
2076 : /*
2077 : * We need the attrs, non-system and system, mentioned in the local
2078 : * query's RETURNING list.
2079 : */
2080 116 : pull_varattnos((Node *) returningList, rtindex,
2081 : &attrs_used);
2082 : }
2083 :
2084 438 : if (attrs_used != NULL)
2085 190 : deparseTargetList(buf, rte, rtindex, rel, true, attrs_used, false,
2086 : retrieved_attrs);
2087 : else
2088 248 : *retrieved_attrs = NIL;
2089 438 : }
2090 :
2091 : /*
2092 : * Construct SELECT statement to acquire size in blocks of given relation.
2093 : *
2094 : * Note: we use local definition of block size, not remote definition.
2095 : * This is perhaps debatable.
2096 : *
2097 : * Note: pg_relation_size() exists in 8.1 and later.
2098 : */
2099 : void
2100 48 : deparseAnalyzeSizeSql(StringInfo buf, Relation rel)
2101 : {
2102 : StringInfoData relname;
2103 :
2104 : /* We'll need the remote relation name as a literal. */
2105 48 : initStringInfo(&relname);
2106 48 : deparseRelation(&relname, rel);
2107 :
2108 48 : appendStringInfoString(buf, "SELECT pg_catalog.pg_relation_size(");
2109 48 : deparseStringLiteral(buf, relname.data);
2110 48 : appendStringInfo(buf, "::pg_catalog.regclass) / %d", BLCKSZ);
2111 48 : }
2112 :
2113 : /*
2114 : * Construct SELECT statement to acquire sample rows of given relation.
2115 : *
2116 : * SELECT command is appended to buf, and list of columns retrieved
2117 : * is returned to *retrieved_attrs.
2118 : */
2119 : void
2120 48 : deparseAnalyzeSql(StringInfo buf, Relation rel, List **retrieved_attrs)
2121 : {
2122 48 : Oid relid = RelationGetRelid(rel);
2123 48 : TupleDesc tupdesc = RelationGetDescr(rel);
2124 : int i;
2125 : char *colname;
2126 : List *options;
2127 : ListCell *lc;
2128 48 : bool first = true;
2129 :
2130 48 : *retrieved_attrs = NIL;
2131 :
2132 48 : appendStringInfoString(buf, "SELECT ");
2133 212 : for (i = 0; i < tupdesc->natts; i++)
2134 : {
2135 : /* Ignore dropped columns. */
2136 164 : if (TupleDescAttr(tupdesc, i)->attisdropped)
2137 4 : continue;
2138 :
2139 160 : if (!first)
2140 112 : appendStringInfoString(buf, ", ");
2141 160 : first = false;
2142 :
2143 : /* Use attribute name or column_name option. */
2144 160 : colname = NameStr(TupleDescAttr(tupdesc, i)->attname);
2145 160 : options = GetForeignColumnOptions(relid, i + 1);
2146 :
2147 160 : foreach(lc, options)
2148 : {
2149 4 : DefElem *def = (DefElem *) lfirst(lc);
2150 :
2151 4 : if (strcmp(def->defname, "column_name") == 0)
2152 : {
2153 4 : colname = defGetString(def);
2154 4 : break;
2155 : }
2156 : }
2157 :
2158 160 : appendStringInfoString(buf, quote_identifier(colname));
2159 :
2160 160 : *retrieved_attrs = lappend_int(*retrieved_attrs, i + 1);
2161 : }
2162 :
2163 : /* Don't generate bad syntax for zero-column relation. */
2164 48 : if (first)
2165 0 : appendStringInfoString(buf, "NULL");
2166 :
2167 : /*
2168 : * Construct FROM clause
2169 : */
2170 48 : appendStringInfoString(buf, " FROM ");
2171 48 : deparseRelation(buf, rel);
2172 48 : }
2173 :
2174 : /*
2175 : * Construct name to use for given column, and emit it into buf.
2176 : * If it has a column_name FDW option, use that instead of attribute name.
2177 : *
2178 : * If qualify_col is true, qualify column name with the alias of relation.
2179 : */
2180 : static void
2181 18960 : deparseColumnRef(StringInfo buf, int varno, int varattno, RangeTblEntry *rte,
2182 : bool qualify_col)
2183 : {
2184 : /* We support fetching the remote side's CTID and OID. */
2185 18960 : if (varattno == SelfItemPointerAttributeNumber)
2186 : {
2187 96 : if (qualify_col)
2188 92 : ADD_REL_QUALIFIER(buf, varno);
2189 96 : appendStringInfoString(buf, "ctid");
2190 : }
2191 18864 : else if (varattno < 0)
2192 : {
2193 : /*
2194 : * All other system attributes are fetched as 0, except for table OID,
2195 : * which is fetched as the local table OID. However, we must be
2196 : * careful; the table could be beneath an outer join, in which case it
2197 : * must go to NULL whenever the rest of the row does.
2198 : */
2199 0 : Oid fetchval = 0;
2200 :
2201 0 : if (varattno == TableOidAttributeNumber)
2202 0 : fetchval = rte->relid;
2203 :
2204 0 : if (qualify_col)
2205 : {
2206 0 : appendStringInfoString(buf, "CASE WHEN (");
2207 0 : ADD_REL_QUALIFIER(buf, varno);
2208 0 : appendStringInfo(buf, "*)::text IS NOT NULL THEN %u END", fetchval);
2209 : }
2210 : else
2211 0 : appendStringInfo(buf, "%u", fetchval);
2212 : }
2213 18864 : else if (varattno == 0)
2214 : {
2215 : /* Whole row reference */
2216 : Relation rel;
2217 : Bitmapset *attrs_used;
2218 :
2219 : /* Required only to be passed down to deparseTargetList(). */
2220 : List *retrieved_attrs;
2221 :
2222 : /*
2223 : * The lock on the relation will be held by upper callers, so it's
2224 : * fine to open it with no lock here.
2225 : */
2226 392 : rel = table_open(rte->relid, NoLock);
2227 :
2228 : /*
2229 : * The local name of the foreign table can not be recognized by the
2230 : * foreign server and the table it references on foreign server might
2231 : * have different column ordering or different columns than those
2232 : * declared locally. Hence we have to deparse whole-row reference as
2233 : * ROW(columns referenced locally). Construct this by deparsing a
2234 : * "whole row" attribute.
2235 : */
2236 392 : attrs_used = bms_add_member(NULL,
2237 : 0 - FirstLowInvalidHeapAttributeNumber);
2238 :
2239 : /*
2240 : * In case the whole-row reference is under an outer join then it has
2241 : * to go NULL whenever the rest of the row goes NULL. Deparsing a join
2242 : * query would always involve multiple relations, thus qualify_col
2243 : * would be true.
2244 : */
2245 392 : if (qualify_col)
2246 : {
2247 384 : appendStringInfoString(buf, "CASE WHEN (");
2248 384 : ADD_REL_QUALIFIER(buf, varno);
2249 384 : appendStringInfoString(buf, "*)::text IS NOT NULL THEN ");
2250 : }
2251 :
2252 392 : appendStringInfoString(buf, "ROW(");
2253 392 : deparseTargetList(buf, rte, varno, rel, false, attrs_used, qualify_col,
2254 : &retrieved_attrs);
2255 392 : appendStringInfoChar(buf, ')');
2256 :
2257 : /* Complete the CASE WHEN statement started above. */
2258 392 : if (qualify_col)
2259 384 : appendStringInfoString(buf, " END");
2260 :
2261 392 : table_close(rel, NoLock);
2262 392 : bms_free(attrs_used);
2263 : }
2264 : else
2265 : {
2266 18472 : char *colname = NULL;
2267 : List *options;
2268 : ListCell *lc;
2269 :
2270 : /* varno must not be any of OUTER_VAR, INNER_VAR and INDEX_VAR. */
2271 : Assert(!IS_SPECIAL_VARNO(varno));
2272 :
2273 : /*
2274 : * If it's a column of a foreign table, and it has the column_name FDW
2275 : * option, use that value.
2276 : */
2277 18472 : options = GetForeignColumnOptions(rte->relid, varattno);
2278 18472 : foreach(lc, options)
2279 : {
2280 4736 : DefElem *def = (DefElem *) lfirst(lc);
2281 :
2282 4736 : if (strcmp(def->defname, "column_name") == 0)
2283 : {
2284 4736 : colname = defGetString(def);
2285 4736 : break;
2286 : }
2287 : }
2288 :
2289 : /*
2290 : * If it's a column of a regular table or it doesn't have column_name
2291 : * FDW option, use attribute name.
2292 : */
2293 18472 : if (colname == NULL)
2294 13736 : colname = get_attname(rte->relid, varattno, false);
2295 :
2296 18472 : if (qualify_col)
2297 8272 : ADD_REL_QUALIFIER(buf, varno);
2298 :
2299 18472 : appendStringInfoString(buf, quote_identifier(colname));
2300 : }
2301 18960 : }
2302 :
2303 : /*
2304 : * Append remote name of specified foreign table to buf.
2305 : * Use value of table_name FDW option (if any) instead of relation's name.
2306 : * Similarly, schema_name FDW option overrides schema name.
2307 : */
2308 : static void
2309 4708 : deparseRelation(StringInfo buf, Relation rel)
2310 : {
2311 : ForeignTable *table;
2312 4708 : const char *nspname = NULL;
2313 4708 : const char *relname = NULL;
2314 : ListCell *lc;
2315 :
2316 : /* obtain additional catalog information. */
2317 4708 : table = GetForeignTable(RelationGetRelid(rel));
2318 :
2319 : /*
2320 : * Use value of FDW options if any, instead of the name of object itself.
2321 : */
2322 15214 : foreach(lc, table->options)
2323 : {
2324 10506 : DefElem *def = (DefElem *) lfirst(lc);
2325 :
2326 10506 : if (strcmp(def->defname, "schema_name") == 0)
2327 3230 : nspname = defGetString(def);
2328 7276 : else if (strcmp(def->defname, "table_name") == 0)
2329 4708 : relname = defGetString(def);
2330 : }
2331 :
2332 : /*
2333 : * Note: we could skip printing the schema name if it's pg_catalog, but
2334 : * that doesn't seem worth the trouble.
2335 : */
2336 4708 : if (nspname == NULL)
2337 1478 : nspname = get_namespace_name(RelationGetNamespace(rel));
2338 4708 : if (relname == NULL)
2339 0 : relname = RelationGetRelationName(rel);
2340 :
2341 4708 : appendStringInfo(buf, "%s.%s",
2342 : quote_identifier(nspname), quote_identifier(relname));
2343 4708 : }
2344 :
2345 : /*
2346 : * Append a SQL string literal representing "val" to buf.
2347 : */
2348 : void
2349 448 : deparseStringLiteral(StringInfo buf, const char *val)
2350 : {
2351 : const char *valptr;
2352 :
2353 : /*
2354 : * Rather than making assumptions about the remote server's value of
2355 : * standard_conforming_strings, always use E'foo' syntax if there are any
2356 : * backslashes. This will fail on remote servers before 8.1, but those
2357 : * are long out of support.
2358 : */
2359 448 : if (strchr(val, '\\') != NULL)
2360 2 : appendStringInfoChar(buf, ESCAPE_STRING_SYNTAX);
2361 448 : appendStringInfoChar(buf, '\'');
2362 3398 : for (valptr = val; *valptr; valptr++)
2363 : {
2364 2950 : char ch = *valptr;
2365 :
2366 2950 : if (SQL_STR_DOUBLE(ch, true))
2367 4 : appendStringInfoChar(buf, ch);
2368 2950 : appendStringInfoChar(buf, ch);
2369 : }
2370 448 : appendStringInfoChar(buf, '\'');
2371 448 : }
2372 :
2373 : /*
2374 : * Deparse given expression into context->buf.
2375 : *
2376 : * This function must support all the same node types that foreign_expr_walker
2377 : * accepts.
2378 : *
2379 : * Note: unlike ruleutils.c, we just use a simple hard-wired parenthesization
2380 : * scheme: anything more complex than a Var, Const, function call or cast
2381 : * should be self-parenthesized.
2382 : */
2383 : static void
2384 16754 : deparseExpr(Expr *node, deparse_expr_cxt *context)
2385 : {
2386 16754 : if (node == NULL)
2387 0 : return;
2388 :
2389 16754 : switch (nodeTag(node))
2390 : {
2391 9730 : case T_Var:
2392 9730 : deparseVar((Var *) node, context);
2393 9730 : break;
2394 2638 : case T_Const:
2395 2638 : deparseConst((Const *) node, context, 0);
2396 2638 : break;
2397 52 : case T_Param:
2398 52 : deparseParam((Param *) node, context);
2399 52 : break;
2400 2 : case T_SubscriptingRef:
2401 2 : deparseSubscriptingRef((SubscriptingRef *) node, context);
2402 2 : break;
2403 94 : case T_FuncExpr:
2404 94 : deparseFuncExpr((FuncExpr *) node, context);
2405 94 : break;
2406 3546 : case T_OpExpr:
2407 3546 : deparseOpExpr((OpExpr *) node, context);
2408 3546 : break;
2409 2 : case T_DistinctExpr:
2410 2 : deparseDistinctExpr((DistinctExpr *) node, context);
2411 2 : break;
2412 8 : case T_ScalarArrayOpExpr:
2413 8 : deparseScalarArrayOpExpr((ScalarArrayOpExpr *) node, context);
2414 8 : break;
2415 64 : case T_RelabelType:
2416 64 : deparseRelabelType((RelabelType *) node, context);
2417 64 : break;
2418 76 : case T_BoolExpr:
2419 76 : deparseBoolExpr((BoolExpr *) node, context);
2420 76 : break;
2421 56 : case T_NullTest:
2422 56 : deparseNullTest((NullTest *) node, context);
2423 56 : break;
2424 8 : case T_ArrayExpr:
2425 8 : deparseArrayExpr((ArrayExpr *) node, context);
2426 8 : break;
2427 478 : case T_Aggref:
2428 478 : deparseAggref((Aggref *) node, context);
2429 478 : break;
2430 0 : default:
2431 0 : elog(ERROR, "unsupported expression type for deparse: %d",
2432 : (int) nodeTag(node));
2433 : break;
2434 : }
2435 : }
2436 :
2437 : /*
2438 : * Deparse given Var node into context->buf.
2439 : *
2440 : * If the Var belongs to the foreign relation, just print its remote name.
2441 : * Otherwise, it's effectively a Param (and will in fact be a Param at
2442 : * run time). Handle it the same way we handle plain Params --- see
2443 : * deparseParam for comments.
2444 : */
2445 : static void
2446 9730 : deparseVar(Var *node, deparse_expr_cxt *context)
2447 : {
2448 9730 : Relids relids = context->scanrel->relids;
2449 : int relno;
2450 : int colno;
2451 :
2452 : /* Qualify columns when multiple relations are involved. */
2453 9730 : bool qualify_col = (bms_membership(relids) == BMS_MULTIPLE);
2454 :
2455 : /*
2456 : * If the Var belongs to the foreign relation that is deparsed as a
2457 : * subquery, use the relation and column alias to the Var provided by the
2458 : * subquery, instead of the remote name.
2459 : */
2460 9730 : if (is_subquery_var(node, context->scanrel, &relno, &colno))
2461 : {
2462 168 : appendStringInfo(context->buf, "%s%d.%s%d",
2463 : SUBQUERY_REL_ALIAS_PREFIX, relno,
2464 : SUBQUERY_COL_ALIAS_PREFIX, colno);
2465 168 : return;
2466 : }
2467 :
2468 9562 : if (bms_is_member(node->varno, relids) && node->varlevelsup == 0)
2469 9282 : deparseColumnRef(context->buf, node->varno, node->varattno,
2470 9282 : planner_rt_fetch(node->varno, context->root),
2471 : qualify_col);
2472 : else
2473 : {
2474 : /* Treat like a Param */
2475 280 : if (context->params_list)
2476 : {
2477 8 : int pindex = 0;
2478 : ListCell *lc;
2479 :
2480 : /* find its index in params_list */
2481 8 : foreach(lc, *context->params_list)
2482 : {
2483 0 : pindex++;
2484 0 : if (equal(node, (Node *) lfirst(lc)))
2485 0 : break;
2486 : }
2487 8 : if (lc == NULL)
2488 : {
2489 : /* not in list, so add it */
2490 8 : pindex++;
2491 8 : *context->params_list = lappend(*context->params_list, node);
2492 : }
2493 :
2494 8 : printRemoteParam(pindex, node->vartype, node->vartypmod, context);
2495 : }
2496 : else
2497 : {
2498 272 : printRemotePlaceholder(node->vartype, node->vartypmod, context);
2499 : }
2500 : }
2501 : }
2502 :
2503 : /*
2504 : * Deparse given constant value into context->buf.
2505 : *
2506 : * This function has to be kept in sync with ruleutils.c's get_const_expr.
2507 : * As for that function, showtype can be -1 to never show "::typename" decoration,
2508 : * or +1 to always show it, or 0 to show it only if the constant wouldn't be assumed
2509 : * to be the right type by default.
2510 : */
2511 : static void
2512 2638 : deparseConst(Const *node, deparse_expr_cxt *context, int showtype)
2513 : {
2514 2638 : StringInfo buf = context->buf;
2515 : Oid typoutput;
2516 : bool typIsVarlena;
2517 : char *extval;
2518 2638 : bool isfloat = false;
2519 : bool needlabel;
2520 :
2521 2638 : if (node->constisnull)
2522 : {
2523 14 : appendStringInfoString(buf, "NULL");
2524 14 : if (showtype >= 0)
2525 14 : appendStringInfo(buf, "::%s",
2526 : deparse_type_name(node->consttype,
2527 : node->consttypmod));
2528 14 : return;
2529 : }
2530 :
2531 2624 : getTypeOutputInfo(node->consttype,
2532 : &typoutput, &typIsVarlena);
2533 2624 : extval = OidOutputFunctionCall(typoutput, node->constvalue);
2534 :
2535 2624 : switch (node->consttype)
2536 : {
2537 2496 : case INT2OID:
2538 : case INT4OID:
2539 : case INT8OID:
2540 : case OIDOID:
2541 : case FLOAT4OID:
2542 : case FLOAT8OID:
2543 : case NUMERICOID:
2544 : {
2545 : /*
2546 : * No need to quote unless it's a special value such as 'NaN'.
2547 : * See comments in get_const_expr().
2548 : */
2549 2496 : if (strspn(extval, "0123456789+-eE.") == strlen(extval))
2550 : {
2551 2496 : if (extval[0] == '+' || extval[0] == '-')
2552 2 : appendStringInfo(buf, "(%s)", extval);
2553 : else
2554 2494 : appendStringInfoString(buf, extval);
2555 2496 : if (strcspn(extval, "eE.") != strlen(extval))
2556 4 : isfloat = true; /* it looks like a float */
2557 : }
2558 : else
2559 0 : appendStringInfo(buf, "'%s'", extval);
2560 : }
2561 2496 : break;
2562 0 : case BITOID:
2563 : case VARBITOID:
2564 0 : appendStringInfo(buf, "B'%s'", extval);
2565 0 : break;
2566 0 : case BOOLOID:
2567 0 : if (strcmp(extval, "t") == 0)
2568 0 : appendStringInfoString(buf, "true");
2569 : else
2570 0 : appendStringInfoString(buf, "false");
2571 0 : break;
2572 128 : default:
2573 128 : deparseStringLiteral(buf, extval);
2574 128 : break;
2575 : }
2576 :
2577 2624 : pfree(extval);
2578 :
2579 2624 : if (showtype < 0)
2580 0 : return;
2581 :
2582 : /*
2583 : * For showtype == 0, append ::typename unless the constant will be
2584 : * implicitly typed as the right type when it is read in.
2585 : *
2586 : * XXX this code has to be kept in sync with the behavior of the parser,
2587 : * especially make_const.
2588 : */
2589 2624 : switch (node->consttype)
2590 : {
2591 2104 : case BOOLOID:
2592 : case INT4OID:
2593 : case UNKNOWNOID:
2594 2104 : needlabel = false;
2595 2104 : break;
2596 42 : case NUMERICOID:
2597 42 : needlabel = !isfloat || (node->consttypmod >= 0);
2598 42 : break;
2599 478 : default:
2600 478 : needlabel = true;
2601 478 : break;
2602 : }
2603 2624 : if (needlabel || showtype > 0)
2604 516 : appendStringInfo(buf, "::%s",
2605 : deparse_type_name(node->consttype,
2606 : node->consttypmod));
2607 : }
2608 :
2609 : /*
2610 : * Deparse given Param node.
2611 : *
2612 : * If we're generating the query "for real", add the Param to
2613 : * context->params_list if it's not already present, and then use its index
2614 : * in that list as the remote parameter number. During EXPLAIN, there's
2615 : * no need to identify a parameter number.
2616 : */
2617 : static void
2618 52 : deparseParam(Param *node, deparse_expr_cxt *context)
2619 : {
2620 52 : if (context->params_list)
2621 : {
2622 32 : int pindex = 0;
2623 : ListCell *lc;
2624 :
2625 : /* find its index in params_list */
2626 36 : foreach(lc, *context->params_list)
2627 : {
2628 4 : pindex++;
2629 4 : if (equal(node, (Node *) lfirst(lc)))
2630 0 : break;
2631 : }
2632 32 : if (lc == NULL)
2633 : {
2634 : /* not in list, so add it */
2635 32 : pindex++;
2636 32 : *context->params_list = lappend(*context->params_list, node);
2637 : }
2638 :
2639 32 : printRemoteParam(pindex, node->paramtype, node->paramtypmod, context);
2640 : }
2641 : else
2642 : {
2643 20 : printRemotePlaceholder(node->paramtype, node->paramtypmod, context);
2644 : }
2645 52 : }
2646 :
2647 : /*
2648 : * Deparse a container subscript expression.
2649 : */
2650 : static void
2651 2 : deparseSubscriptingRef(SubscriptingRef *node, deparse_expr_cxt *context)
2652 : {
2653 2 : StringInfo buf = context->buf;
2654 : ListCell *lowlist_item;
2655 : ListCell *uplist_item;
2656 :
2657 : /* Always parenthesize the expression. */
2658 2 : appendStringInfoChar(buf, '(');
2659 :
2660 : /*
2661 : * Deparse referenced array expression first. If that expression includes
2662 : * a cast, we have to parenthesize to prevent the array subscript from
2663 : * being taken as typename decoration. We can avoid that in the typical
2664 : * case of subscripting a Var, but otherwise do it.
2665 : */
2666 2 : if (IsA(node->refexpr, Var))
2667 0 : deparseExpr(node->refexpr, context);
2668 : else
2669 : {
2670 2 : appendStringInfoChar(buf, '(');
2671 2 : deparseExpr(node->refexpr, context);
2672 2 : appendStringInfoChar(buf, ')');
2673 : }
2674 :
2675 : /* Deparse subscript expressions. */
2676 2 : lowlist_item = list_head(node->reflowerindexpr); /* could be NULL */
2677 4 : foreach(uplist_item, node->refupperindexpr)
2678 : {
2679 2 : appendStringInfoChar(buf, '[');
2680 2 : if (lowlist_item)
2681 : {
2682 0 : deparseExpr(lfirst(lowlist_item), context);
2683 0 : appendStringInfoChar(buf, ':');
2684 0 : lowlist_item = lnext(node->reflowerindexpr, lowlist_item);
2685 : }
2686 2 : deparseExpr(lfirst(uplist_item), context);
2687 2 : appendStringInfoChar(buf, ']');
2688 : }
2689 :
2690 2 : appendStringInfoChar(buf, ')');
2691 2 : }
2692 :
2693 : /*
2694 : * Deparse a function call.
2695 : */
2696 : static void
2697 94 : deparseFuncExpr(FuncExpr *node, deparse_expr_cxt *context)
2698 : {
2699 94 : StringInfo buf = context->buf;
2700 : bool use_variadic;
2701 : bool first;
2702 : ListCell *arg;
2703 :
2704 : /*
2705 : * If the function call came from an implicit coercion, then just show the
2706 : * first argument.
2707 : */
2708 94 : if (node->funcformat == COERCE_IMPLICIT_CAST)
2709 : {
2710 42 : deparseExpr((Expr *) linitial(node->args), context);
2711 42 : return;
2712 : }
2713 :
2714 : /*
2715 : * If the function call came from a cast, then show the first argument
2716 : * plus an explicit cast operation.
2717 : */
2718 52 : if (node->funcformat == COERCE_EXPLICIT_CAST)
2719 : {
2720 0 : Oid rettype = node->funcresulttype;
2721 : int32 coercedTypmod;
2722 :
2723 : /* Get the typmod if this is a length-coercion function */
2724 0 : (void) exprIsLengthCoercion((Node *) node, &coercedTypmod);
2725 :
2726 0 : deparseExpr((Expr *) linitial(node->args), context);
2727 0 : appendStringInfo(buf, "::%s",
2728 : deparse_type_name(rettype, coercedTypmod));
2729 0 : return;
2730 : }
2731 :
2732 : /* Check if need to print VARIADIC (cf. ruleutils.c) */
2733 52 : use_variadic = node->funcvariadic;
2734 :
2735 : /*
2736 : * Normal function: display as proname(args).
2737 : */
2738 52 : appendFunctionName(node->funcid, context);
2739 52 : appendStringInfoChar(buf, '(');
2740 :
2741 : /* ... and all the arguments */
2742 52 : first = true;
2743 106 : foreach(arg, node->args)
2744 : {
2745 54 : if (!first)
2746 2 : appendStringInfoString(buf, ", ");
2747 54 : if (use_variadic && lnext(node->args, arg) == NULL)
2748 0 : appendStringInfoString(buf, "VARIADIC ");
2749 54 : deparseExpr((Expr *) lfirst(arg), context);
2750 54 : first = false;
2751 : }
2752 52 : appendStringInfoChar(buf, ')');
2753 : }
2754 :
2755 : /*
2756 : * Deparse given operator expression. To avoid problems around
2757 : * priority of operations, we always parenthesize the arguments.
2758 : */
2759 : static void
2760 3546 : deparseOpExpr(OpExpr *node, deparse_expr_cxt *context)
2761 : {
2762 3546 : StringInfo buf = context->buf;
2763 : HeapTuple tuple;
2764 : Form_pg_operator form;
2765 : char oprkind;
2766 :
2767 : /* Retrieve information about the operator from system catalog. */
2768 3546 : tuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(node->opno));
2769 3546 : if (!HeapTupleIsValid(tuple))
2770 0 : elog(ERROR, "cache lookup failed for operator %u", node->opno);
2771 3546 : form = (Form_pg_operator) GETSTRUCT(tuple);
2772 3546 : oprkind = form->oprkind;
2773 :
2774 : /* Sanity check. */
2775 : Assert((oprkind == 'l' && list_length(node->args) == 1) ||
2776 : (oprkind == 'b' && list_length(node->args) == 2));
2777 :
2778 : /* Always parenthesize the expression. */
2779 3546 : appendStringInfoChar(buf, '(');
2780 :
2781 : /* Deparse left operand, if any. */
2782 3546 : if (oprkind == 'b')
2783 : {
2784 3540 : deparseExpr(linitial(node->args), context);
2785 3540 : appendStringInfoChar(buf, ' ');
2786 : }
2787 :
2788 : /* Deparse operator name. */
2789 3546 : deparseOperatorName(buf, form);
2790 :
2791 : /* Deparse right operand. */
2792 3546 : appendStringInfoChar(buf, ' ');
2793 3546 : deparseExpr(llast(node->args), context);
2794 :
2795 3546 : appendStringInfoChar(buf, ')');
2796 :
2797 3546 : ReleaseSysCache(tuple);
2798 3546 : }
2799 :
2800 : /*
2801 : * Print the name of an operator.
2802 : */
2803 : static void
2804 3562 : deparseOperatorName(StringInfo buf, Form_pg_operator opform)
2805 : {
2806 : char *opname;
2807 :
2808 : /* opname is not a SQL identifier, so we should not quote it. */
2809 3562 : opname = NameStr(opform->oprname);
2810 :
2811 : /* Print schema name only if it's not pg_catalog */
2812 3562 : if (opform->oprnamespace != PG_CATALOG_NAMESPACE)
2813 : {
2814 : const char *opnspname;
2815 :
2816 18 : opnspname = get_namespace_name(opform->oprnamespace);
2817 : /* Print fully qualified operator name. */
2818 18 : appendStringInfo(buf, "OPERATOR(%s.%s)",
2819 : quote_identifier(opnspname), opname);
2820 : }
2821 : else
2822 : {
2823 : /* Just print operator name. */
2824 3544 : appendStringInfoString(buf, opname);
2825 : }
2826 3562 : }
2827 :
2828 : /*
2829 : * Deparse IS DISTINCT FROM.
2830 : */
2831 : static void
2832 2 : deparseDistinctExpr(DistinctExpr *node, deparse_expr_cxt *context)
2833 : {
2834 2 : StringInfo buf = context->buf;
2835 :
2836 : Assert(list_length(node->args) == 2);
2837 :
2838 2 : appendStringInfoChar(buf, '(');
2839 2 : deparseExpr(linitial(node->args), context);
2840 2 : appendStringInfoString(buf, " IS DISTINCT FROM ");
2841 2 : deparseExpr(lsecond(node->args), context);
2842 2 : appendStringInfoChar(buf, ')');
2843 2 : }
2844 :
2845 : /*
2846 : * Deparse given ScalarArrayOpExpr expression. To avoid problems
2847 : * around priority of operations, we always parenthesize the arguments.
2848 : */
2849 : static void
2850 8 : deparseScalarArrayOpExpr(ScalarArrayOpExpr *node, deparse_expr_cxt *context)
2851 : {
2852 8 : StringInfo buf = context->buf;
2853 : HeapTuple tuple;
2854 : Form_pg_operator form;
2855 : Expr *arg1;
2856 : Expr *arg2;
2857 :
2858 : /* Retrieve information about the operator from system catalog. */
2859 8 : tuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(node->opno));
2860 8 : if (!HeapTupleIsValid(tuple))
2861 0 : elog(ERROR, "cache lookup failed for operator %u", node->opno);
2862 8 : form = (Form_pg_operator) GETSTRUCT(tuple);
2863 :
2864 : /* Sanity check. */
2865 : Assert(list_length(node->args) == 2);
2866 :
2867 : /* Always parenthesize the expression. */
2868 8 : appendStringInfoChar(buf, '(');
2869 :
2870 : /* Deparse left operand. */
2871 8 : arg1 = linitial(node->args);
2872 8 : deparseExpr(arg1, context);
2873 8 : appendStringInfoChar(buf, ' ');
2874 :
2875 : /* Deparse operator name plus decoration. */
2876 8 : deparseOperatorName(buf, form);
2877 8 : appendStringInfo(buf, " %s (", node->useOr ? "ANY" : "ALL");
2878 :
2879 : /* Deparse right operand. */
2880 8 : arg2 = lsecond(node->args);
2881 8 : deparseExpr(arg2, context);
2882 :
2883 8 : appendStringInfoChar(buf, ')');
2884 :
2885 : /* Always parenthesize the expression. */
2886 8 : appendStringInfoChar(buf, ')');
2887 :
2888 8 : ReleaseSysCache(tuple);
2889 8 : }
2890 :
2891 : /*
2892 : * Deparse a RelabelType (binary-compatible cast) node.
2893 : */
2894 : static void
2895 64 : deparseRelabelType(RelabelType *node, deparse_expr_cxt *context)
2896 : {
2897 64 : deparseExpr(node->arg, context);
2898 64 : if (node->relabelformat != COERCE_IMPLICIT_CAST)
2899 0 : appendStringInfo(context->buf, "::%s",
2900 : deparse_type_name(node->resulttype,
2901 : node->resulttypmod));
2902 64 : }
2903 :
2904 : /*
2905 : * Deparse a BoolExpr node.
2906 : */
2907 : static void
2908 76 : deparseBoolExpr(BoolExpr *node, deparse_expr_cxt *context)
2909 : {
2910 76 : StringInfo buf = context->buf;
2911 76 : const char *op = NULL; /* keep compiler quiet */
2912 : bool first;
2913 : ListCell *lc;
2914 :
2915 76 : switch (node->boolop)
2916 : {
2917 36 : case AND_EXPR:
2918 36 : op = "AND";
2919 36 : break;
2920 40 : case OR_EXPR:
2921 40 : op = "OR";
2922 40 : break;
2923 0 : case NOT_EXPR:
2924 0 : appendStringInfoString(buf, "(NOT ");
2925 0 : deparseExpr(linitial(node->args), context);
2926 0 : appendStringInfoChar(buf, ')');
2927 0 : return;
2928 : }
2929 :
2930 76 : appendStringInfoChar(buf, '(');
2931 76 : first = true;
2932 228 : foreach(lc, node->args)
2933 : {
2934 152 : if (!first)
2935 76 : appendStringInfo(buf, " %s ", op);
2936 152 : deparseExpr((Expr *) lfirst(lc), context);
2937 152 : first = false;
2938 : }
2939 76 : appendStringInfoChar(buf, ')');
2940 : }
2941 :
2942 : /*
2943 : * Deparse IS [NOT] NULL expression.
2944 : */
2945 : static void
2946 56 : deparseNullTest(NullTest *node, deparse_expr_cxt *context)
2947 : {
2948 56 : StringInfo buf = context->buf;
2949 :
2950 56 : appendStringInfoChar(buf, '(');
2951 56 : deparseExpr(node->arg, context);
2952 :
2953 : /*
2954 : * For scalar inputs, we prefer to print as IS [NOT] NULL, which is
2955 : * shorter and traditional. If it's a rowtype input but we're applying a
2956 : * scalar test, must print IS [NOT] DISTINCT FROM NULL to be semantically
2957 : * correct.
2958 : */
2959 56 : if (node->argisrow || !type_is_rowtype(exprType((Node *) node->arg)))
2960 : {
2961 112 : if (node->nulltesttype == IS_NULL)
2962 38 : appendStringInfoString(buf, " IS NULL)");
2963 : else
2964 18 : appendStringInfoString(buf, " IS NOT NULL)");
2965 : }
2966 : else
2967 : {
2968 0 : if (node->nulltesttype == IS_NULL)
2969 0 : appendStringInfoString(buf, " IS NOT DISTINCT FROM NULL)");
2970 : else
2971 0 : appendStringInfoString(buf, " IS DISTINCT FROM NULL)");
2972 : }
2973 56 : }
2974 :
2975 : /*
2976 : * Deparse ARRAY[...] construct.
2977 : */
2978 : static void
2979 8 : deparseArrayExpr(ArrayExpr *node, deparse_expr_cxt *context)
2980 : {
2981 8 : StringInfo buf = context->buf;
2982 8 : bool first = true;
2983 : ListCell *lc;
2984 :
2985 8 : appendStringInfoString(buf, "ARRAY[");
2986 24 : foreach(lc, node->elements)
2987 : {
2988 16 : if (!first)
2989 8 : appendStringInfoString(buf, ", ");
2990 16 : deparseExpr(lfirst(lc), context);
2991 16 : first = false;
2992 : }
2993 8 : appendStringInfoChar(buf, ']');
2994 :
2995 : /* If the array is empty, we need an explicit cast to the array type. */
2996 8 : if (node->elements == NIL)
2997 0 : appendStringInfo(buf, "::%s",
2998 : deparse_type_name(node->array_typeid, -1));
2999 8 : }
3000 :
3001 : /*
3002 : * Deparse an Aggref node.
3003 : */
3004 : static void
3005 478 : deparseAggref(Aggref *node, deparse_expr_cxt *context)
3006 : {
3007 478 : StringInfo buf = context->buf;
3008 : bool use_variadic;
3009 :
3010 : /* Only basic, non-split aggregation accepted. */
3011 : Assert(node->aggsplit == AGGSPLIT_SIMPLE);
3012 :
3013 : /* Check if need to print VARIADIC (cf. ruleutils.c) */
3014 478 : use_variadic = node->aggvariadic;
3015 :
3016 : /* Find aggregate name from aggfnoid which is a pg_proc entry */
3017 478 : appendFunctionName(node->aggfnoid, context);
3018 478 : appendStringInfoChar(buf, '(');
3019 :
3020 : /* Add DISTINCT */
3021 478 : appendStringInfoString(buf, (node->aggdistinct != NIL) ? "DISTINCT " : "");
3022 :
3023 478 : if (AGGKIND_IS_ORDERED_SET(node->aggkind))
3024 : {
3025 : /* Add WITHIN GROUP (ORDER BY ..) */
3026 : ListCell *arg;
3027 16 : bool first = true;
3028 :
3029 : Assert(!node->aggvariadic);
3030 : Assert(node->aggorder != NIL);
3031 :
3032 36 : foreach(arg, node->aggdirectargs)
3033 : {
3034 20 : if (!first)
3035 4 : appendStringInfoString(buf, ", ");
3036 20 : first = false;
3037 :
3038 20 : deparseExpr((Expr *) lfirst(arg), context);
3039 : }
3040 :
3041 16 : appendStringInfoString(buf, ") WITHIN GROUP (ORDER BY ");
3042 16 : appendAggOrderBy(node->aggorder, node->args, context);
3043 : }
3044 : else
3045 : {
3046 : /* aggstar can be set only in zero-argument aggregates */
3047 462 : if (node->aggstar)
3048 104 : appendStringInfoChar(buf, '*');
3049 : else
3050 : {
3051 : ListCell *arg;
3052 358 : bool first = true;
3053 :
3054 : /* Add all the arguments */
3055 724 : foreach(arg, node->args)
3056 : {
3057 366 : TargetEntry *tle = (TargetEntry *) lfirst(arg);
3058 366 : Node *n = (Node *) tle->expr;
3059 :
3060 366 : if (tle->resjunk)
3061 8 : continue;
3062 :
3063 358 : if (!first)
3064 0 : appendStringInfoString(buf, ", ");
3065 358 : first = false;
3066 :
3067 : /* Add VARIADIC */
3068 358 : if (use_variadic && lnext(node->args, arg) == NULL)
3069 4 : appendStringInfoString(buf, "VARIADIC ");
3070 :
3071 358 : deparseExpr((Expr *) n, context);
3072 : }
3073 : }
3074 :
3075 : /* Add ORDER BY */
3076 462 : if (node->aggorder != NIL)
3077 : {
3078 44 : appendStringInfoString(buf, " ORDER BY ");
3079 44 : appendAggOrderBy(node->aggorder, node->args, context);
3080 : }
3081 : }
3082 :
3083 : /* Add FILTER (WHERE ..) */
3084 478 : if (node->aggfilter != NULL)
3085 : {
3086 24 : appendStringInfoString(buf, ") FILTER (WHERE ");
3087 24 : deparseExpr((Expr *) node->aggfilter, context);
3088 : }
3089 :
3090 478 : appendStringInfoChar(buf, ')');
3091 478 : }
3092 :
3093 : /*
3094 : * Append ORDER BY within aggregate function.
3095 : */
3096 : static void
3097 60 : appendAggOrderBy(List *orderList, List *targetList, deparse_expr_cxt *context)
3098 : {
3099 60 : StringInfo buf = context->buf;
3100 : ListCell *lc;
3101 60 : bool first = true;
3102 :
3103 124 : foreach(lc, orderList)
3104 : {
3105 64 : SortGroupClause *srt = (SortGroupClause *) lfirst(lc);
3106 : Node *sortexpr;
3107 : Oid sortcoltype;
3108 : TypeCacheEntry *typentry;
3109 :
3110 64 : if (!first)
3111 4 : appendStringInfoString(buf, ", ");
3112 64 : first = false;
3113 :
3114 64 : sortexpr = deparseSortGroupClause(srt->tleSortGroupRef, targetList,
3115 : false, context);
3116 64 : sortcoltype = exprType(sortexpr);
3117 : /* See whether operator is default < or > for datatype */
3118 64 : typentry = lookup_type_cache(sortcoltype,
3119 : TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
3120 64 : if (srt->sortop == typentry->lt_opr)
3121 40 : appendStringInfoString(buf, " ASC");
3122 24 : else if (srt->sortop == typentry->gt_opr)
3123 16 : appendStringInfoString(buf, " DESC");
3124 : else
3125 : {
3126 : HeapTuple opertup;
3127 : Form_pg_operator operform;
3128 :
3129 8 : appendStringInfoString(buf, " USING ");
3130 :
3131 : /* Append operator name. */
3132 8 : opertup = SearchSysCache1(OPEROID, ObjectIdGetDatum(srt->sortop));
3133 8 : if (!HeapTupleIsValid(opertup))
3134 0 : elog(ERROR, "cache lookup failed for operator %u", srt->sortop);
3135 8 : operform = (Form_pg_operator) GETSTRUCT(opertup);
3136 8 : deparseOperatorName(buf, operform);
3137 8 : ReleaseSysCache(opertup);
3138 : }
3139 :
3140 64 : if (srt->nulls_first)
3141 8 : appendStringInfoString(buf, " NULLS FIRST");
3142 : else
3143 56 : appendStringInfoString(buf, " NULLS LAST");
3144 : }
3145 60 : }
3146 :
3147 : /*
3148 : * Print the representation of a parameter to be sent to the remote side.
3149 : *
3150 : * Note: we always label the Param's type explicitly rather than relying on
3151 : * transmitting a numeric type OID in PQexecParams(). This allows us to
3152 : * avoid assuming that types have the same OIDs on the remote side as they
3153 : * do locally --- they need only have the same names.
3154 : */
3155 : static void
3156 40 : printRemoteParam(int paramindex, Oid paramtype, int32 paramtypmod,
3157 : deparse_expr_cxt *context)
3158 : {
3159 40 : StringInfo buf = context->buf;
3160 40 : char *ptypename = deparse_type_name(paramtype, paramtypmod);
3161 :
3162 40 : appendStringInfo(buf, "$%d::%s", paramindex, ptypename);
3163 40 : }
3164 :
3165 : /*
3166 : * Print the representation of a placeholder for a parameter that will be
3167 : * sent to the remote side at execution time.
3168 : *
3169 : * This is used when we're just trying to EXPLAIN the remote query.
3170 : * We don't have the actual value of the runtime parameter yet, and we don't
3171 : * want the remote planner to generate a plan that depends on such a value
3172 : * anyway. Thus, we can't do something simple like "$1::paramtype".
3173 : * Instead, we emit "((SELECT null::paramtype)::paramtype)".
3174 : * In all extant versions of Postgres, the planner will see that as an unknown
3175 : * constant value, which is what we want. This might need adjustment if we
3176 : * ever make the planner flatten scalar subqueries. Note: the reason for the
3177 : * apparently useless outer cast is to ensure that the representation as a
3178 : * whole will be parsed as an a_expr and not a select_with_parens; the latter
3179 : * would do the wrong thing in the context "x = ANY(...)".
3180 : */
3181 : static void
3182 292 : printRemotePlaceholder(Oid paramtype, int32 paramtypmod,
3183 : deparse_expr_cxt *context)
3184 : {
3185 292 : StringInfo buf = context->buf;
3186 292 : char *ptypename = deparse_type_name(paramtype, paramtypmod);
3187 :
3188 292 : appendStringInfo(buf, "((SELECT null::%s)::%s)", ptypename, ptypename);
3189 292 : }
3190 :
3191 : /*
3192 : * Deparse GROUP BY clause.
3193 : */
3194 : static void
3195 284 : appendGroupByClause(List *tlist, deparse_expr_cxt *context)
3196 : {
3197 284 : StringInfo buf = context->buf;
3198 284 : Query *query = context->root->parse;
3199 : ListCell *lc;
3200 284 : bool first = true;
3201 :
3202 : /* Nothing to be done, if there's no GROUP BY clause in the query. */
3203 284 : if (!query->groupClause)
3204 82 : return;
3205 :
3206 202 : appendStringInfoString(buf, " GROUP BY ");
3207 :
3208 : /*
3209 : * Queries with grouping sets are not pushed down, so we don't expect
3210 : * grouping sets here.
3211 : */
3212 : Assert(!query->groupingSets);
3213 :
3214 428 : foreach(lc, query->groupClause)
3215 : {
3216 226 : SortGroupClause *grp = (SortGroupClause *) lfirst(lc);
3217 :
3218 226 : if (!first)
3219 24 : appendStringInfoString(buf, ", ");
3220 226 : first = false;
3221 :
3222 226 : deparseSortGroupClause(grp->tleSortGroupRef, tlist, true, context);
3223 : }
3224 : }
3225 :
3226 : /*
3227 : * Deparse ORDER BY clause according to the given pathkeys for given base
3228 : * relation. From given pathkeys expressions belonging entirely to the given
3229 : * base relation are obtained and deparsed.
3230 : */
3231 : static void
3232 922 : appendOrderByClause(List *pathkeys, bool has_final_sort,
3233 : deparse_expr_cxt *context)
3234 : {
3235 : ListCell *lcell;
3236 : int nestlevel;
3237 922 : char *delim = " ";
3238 922 : RelOptInfo *baserel = context->scanrel;
3239 922 : StringInfo buf = context->buf;
3240 :
3241 : /* Make sure any constants in the exprs are printed portably */
3242 922 : nestlevel = set_transmission_modes();
3243 :
3244 922 : appendStringInfoString(buf, " ORDER BY");
3245 2100 : foreach(lcell, pathkeys)
3246 : {
3247 1178 : PathKey *pathkey = lfirst(lcell);
3248 : Expr *em_expr;
3249 :
3250 1178 : if (has_final_sort)
3251 : {
3252 : /*
3253 : * By construction, context->foreignrel is the input relation to
3254 : * the final sort.
3255 : */
3256 338 : em_expr = find_em_expr_for_input_target(context->root,
3257 : pathkey->pk_eclass,
3258 338 : context->foreignrel->reltarget);
3259 : }
3260 : else
3261 840 : em_expr = find_em_expr_for_rel(pathkey->pk_eclass, baserel);
3262 :
3263 : Assert(em_expr != NULL);
3264 :
3265 1178 : appendStringInfoString(buf, delim);
3266 1178 : deparseExpr(em_expr, context);
3267 1178 : if (pathkey->pk_strategy == BTLessStrategyNumber)
3268 1168 : appendStringInfoString(buf, " ASC");
3269 : else
3270 10 : appendStringInfoString(buf, " DESC");
3271 :
3272 1178 : if (pathkey->pk_nulls_first)
3273 10 : appendStringInfoString(buf, " NULLS FIRST");
3274 : else
3275 1168 : appendStringInfoString(buf, " NULLS LAST");
3276 :
3277 1178 : delim = ", ";
3278 : }
3279 922 : reset_transmission_modes(nestlevel);
3280 922 : }
3281 :
3282 : /*
3283 : * Deparse LIMIT/OFFSET clause.
3284 : */
3285 : static void
3286 204 : appendLimitClause(deparse_expr_cxt *context)
3287 : {
3288 204 : PlannerInfo *root = context->root;
3289 204 : StringInfo buf = context->buf;
3290 : int nestlevel;
3291 :
3292 : /* Make sure any constants in the exprs are printed portably */
3293 204 : nestlevel = set_transmission_modes();
3294 :
3295 204 : if (root->parse->limitCount)
3296 : {
3297 204 : appendStringInfoString(buf, " LIMIT ");
3298 204 : deparseExpr((Expr *) root->parse->limitCount, context);
3299 : }
3300 204 : if (root->parse->limitOffset)
3301 : {
3302 142 : appendStringInfoString(buf, " OFFSET ");
3303 142 : deparseExpr((Expr *) root->parse->limitOffset, context);
3304 : }
3305 :
3306 204 : reset_transmission_modes(nestlevel);
3307 204 : }
3308 :
3309 : /*
3310 : * appendFunctionName
3311 : * Deparses function name from given function oid.
3312 : */
3313 : static void
3314 530 : appendFunctionName(Oid funcid, deparse_expr_cxt *context)
3315 : {
3316 530 : StringInfo buf = context->buf;
3317 : HeapTuple proctup;
3318 : Form_pg_proc procform;
3319 : const char *proname;
3320 :
3321 530 : proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
3322 530 : if (!HeapTupleIsValid(proctup))
3323 0 : elog(ERROR, "cache lookup failed for function %u", funcid);
3324 530 : procform = (Form_pg_proc) GETSTRUCT(proctup);
3325 :
3326 : /* Print schema name only if it's not pg_catalog */
3327 530 : if (procform->pronamespace != PG_CATALOG_NAMESPACE)
3328 : {
3329 : const char *schemaname;
3330 :
3331 12 : schemaname = get_namespace_name(procform->pronamespace);
3332 12 : appendStringInfo(buf, "%s.", quote_identifier(schemaname));
3333 : }
3334 :
3335 : /* Always print the function name */
3336 530 : proname = NameStr(procform->proname);
3337 530 : appendStringInfoString(buf, quote_identifier(proname));
3338 :
3339 530 : ReleaseSysCache(proctup);
3340 530 : }
3341 :
3342 : /*
3343 : * Appends a sort or group clause.
3344 : *
3345 : * Like get_rule_sortgroupclause(), returns the expression tree, so caller
3346 : * need not find it again.
3347 : */
3348 : static Node *
3349 290 : deparseSortGroupClause(Index ref, List *tlist, bool force_colno,
3350 : deparse_expr_cxt *context)
3351 : {
3352 290 : StringInfo buf = context->buf;
3353 : TargetEntry *tle;
3354 : Expr *expr;
3355 :
3356 290 : tle = get_sortgroupref_tle(ref, tlist);
3357 290 : expr = tle->expr;
3358 :
3359 290 : if (force_colno)
3360 : {
3361 : /* Use column-number form when requested by caller. */
3362 : Assert(!tle->resjunk);
3363 226 : appendStringInfo(buf, "%d", tle->resno);
3364 : }
3365 64 : else if (expr && IsA(expr, Const))
3366 : {
3367 : /*
3368 : * Force a typecast here so that we don't emit something like "GROUP
3369 : * BY 2", which will be misconstrued as a column position rather than
3370 : * a constant.
3371 : */
3372 0 : deparseConst((Const *) expr, context, 1);
3373 : }
3374 64 : else if (!expr || IsA(expr, Var))
3375 36 : deparseExpr(expr, context);
3376 : else
3377 : {
3378 : /* Always parenthesize the expression. */
3379 28 : appendStringInfoChar(buf, '(');
3380 28 : deparseExpr(expr, context);
3381 28 : appendStringInfoChar(buf, ')');
3382 : }
3383 :
3384 290 : return (Node *) expr;
3385 : }
3386 :
3387 :
3388 : /*
3389 : * Returns true if given Var is deparsed as a subquery output column, in
3390 : * which case, *relno and *colno are set to the IDs for the relation and
3391 : * column alias to the Var provided by the subquery.
3392 : */
3393 : static bool
3394 9730 : is_subquery_var(Var *node, RelOptInfo *foreignrel, int *relno, int *colno)
3395 : {
3396 9730 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
3397 9730 : RelOptInfo *outerrel = fpinfo->outerrel;
3398 9730 : RelOptInfo *innerrel = fpinfo->innerrel;
3399 :
3400 : /* Should only be called in these cases. */
3401 : Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
3402 :
3403 : /*
3404 : * If the given relation isn't a join relation, it doesn't have any lower
3405 : * subqueries, so the Var isn't a subquery output column.
3406 : */
3407 9730 : if (!IS_JOIN_REL(foreignrel))
3408 3138 : return false;
3409 :
3410 : /*
3411 : * If the Var doesn't belong to any lower subqueries, it isn't a subquery
3412 : * output column.
3413 : */
3414 6592 : if (!bms_is_member(node->varno, fpinfo->lower_subquery_rels))
3415 6424 : return false;
3416 :
3417 168 : if (bms_is_member(node->varno, outerrel->relids))
3418 : {
3419 : /*
3420 : * If outer relation is deparsed as a subquery, the Var is an output
3421 : * column of the subquery; get the IDs for the relation/column alias.
3422 : */
3423 84 : if (fpinfo->make_outerrel_subquery)
3424 : {
3425 84 : get_relation_column_alias_ids(node, outerrel, relno, colno);
3426 84 : return true;
3427 : }
3428 :
3429 : /* Otherwise, recurse into the outer relation. */
3430 0 : return is_subquery_var(node, outerrel, relno, colno);
3431 : }
3432 : else
3433 : {
3434 : Assert(bms_is_member(node->varno, innerrel->relids));
3435 :
3436 : /*
3437 : * If inner relation is deparsed as a subquery, the Var is an output
3438 : * column of the subquery; get the IDs for the relation/column alias.
3439 : */
3440 84 : if (fpinfo->make_innerrel_subquery)
3441 : {
3442 84 : get_relation_column_alias_ids(node, innerrel, relno, colno);
3443 84 : return true;
3444 : }
3445 :
3446 : /* Otherwise, recurse into the inner relation. */
3447 0 : return is_subquery_var(node, innerrel, relno, colno);
3448 : }
3449 : }
3450 :
3451 : /*
3452 : * Get the IDs for the relation and column alias to given Var belonging to
3453 : * given relation, which are returned into *relno and *colno.
3454 : */
3455 : static void
3456 168 : get_relation_column_alias_ids(Var *node, RelOptInfo *foreignrel,
3457 : int *relno, int *colno)
3458 : {
3459 168 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
3460 : int i;
3461 : ListCell *lc;
3462 :
3463 : /* Get the relation alias ID */
3464 168 : *relno = fpinfo->relation_index;
3465 :
3466 : /* Get the column alias ID */
3467 168 : i = 1;
3468 192 : foreach(lc, foreignrel->reltarget->exprs)
3469 : {
3470 192 : if (equal(lfirst(lc), (Node *) node))
3471 : {
3472 168 : *colno = i;
3473 168 : return;
3474 : }
3475 24 : i++;
3476 : }
3477 :
3478 : /* Shouldn't get here */
3479 0 : elog(ERROR, "unexpected expression in subquery output");
3480 : }
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