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) 2012-2019, PostgreSQL Global Development Group
28 : *
29 : * IDENTIFICATION
30 : * contrib/postgres_fdw/deparse.c
31 : *
32 : *-------------------------------------------------------------------------
33 : */
34 : #include "postgres.h"
35 :
36 : #include "postgres_fdw.h"
37 :
38 : #include "access/htup_details.h"
39 : #include "access/sysattr.h"
40 : #include "access/table.h"
41 : #include "catalog/pg_aggregate.h"
42 : #include "catalog/pg_collation.h"
43 : #include "catalog/pg_namespace.h"
44 : #include "catalog/pg_operator.h"
45 : #include "catalog/pg_proc.h"
46 : #include "catalog/pg_type.h"
47 : #include "commands/defrem.h"
48 : #include "nodes/makefuncs.h"
49 : #include "nodes/nodeFuncs.h"
50 : #include "nodes/plannodes.h"
51 : #include "optimizer/optimizer.h"
52 : #include "optimizer/prep.h"
53 : #include "optimizer/tlist.h"
54 : #include "parser/parsetree.h"
55 : #include "utils/builtins.h"
56 : #include "utils/lsyscache.h"
57 : #include "utils/rel.h"
58 : #include "utils/syscache.h"
59 : #include "utils/typcache.h"
60 :
61 :
62 : /*
63 : * Global context for foreign_expr_walker's search of an expression tree.
64 : */
65 : typedef struct foreign_glob_cxt
66 : {
67 : PlannerInfo *root; /* global planner state */
68 : RelOptInfo *foreignrel; /* the foreign relation we are planning for */
69 : Relids relids; /* relids of base relations in the underlying
70 : * scan */
71 : } foreign_glob_cxt;
72 :
73 : /*
74 : * Local (per-tree-level) context for foreign_expr_walker's search.
75 : * This is concerned with identifying collations used in the expression.
76 : */
77 : typedef enum
78 : {
79 : FDW_COLLATE_NONE, /* expression is of a noncollatable type, or
80 : * it has default collation that is not
81 : * traceable to a foreign Var */
82 : FDW_COLLATE_SAFE, /* collation derives from a foreign Var */
83 : FDW_COLLATE_UNSAFE /* collation is non-default and derives from
84 : * something other than a foreign Var */
85 : } FDWCollateState;
86 :
87 : typedef struct foreign_loc_cxt
88 : {
89 : Oid collation; /* OID of current collation, if any */
90 : FDWCollateState state; /* state of current collation choice */
91 : } foreign_loc_cxt;
92 :
93 : /*
94 : * Context for deparseExpr
95 : */
96 : typedef struct deparse_expr_cxt
97 : {
98 : PlannerInfo *root; /* global planner state */
99 : RelOptInfo *foreignrel; /* the foreign relation we are planning for */
100 : RelOptInfo *scanrel; /* the underlying scan relation. Same as
101 : * foreignrel, when that represents a join or
102 : * a base relation. */
103 : StringInfo buf; /* output buffer to append to */
104 : List **params_list; /* exprs that will become remote Params */
105 : } deparse_expr_cxt;
106 :
107 : #define REL_ALIAS_PREFIX "r"
108 : /* Handy macro to add relation name qualification */
109 : #define ADD_REL_QUALIFIER(buf, varno) \
110 : appendStringInfo((buf), "%s%d.", REL_ALIAS_PREFIX, (varno))
111 : #define SUBQUERY_REL_ALIAS_PREFIX "s"
112 : #define SUBQUERY_COL_ALIAS_PREFIX "c"
113 :
114 : /*
115 : * Functions to determine whether an expression can be evaluated safely on
116 : * remote server.
117 : */
118 : static bool foreign_expr_walker(Node *node,
119 : foreign_glob_cxt *glob_cxt,
120 : foreign_loc_cxt *outer_cxt);
121 : static char *deparse_type_name(Oid type_oid, int32 typemod);
122 :
123 : /*
124 : * Functions to construct string representation of a node tree.
125 : */
126 : static void deparseTargetList(StringInfo buf,
127 : RangeTblEntry *rte,
128 : Index rtindex,
129 : Relation rel,
130 : bool is_returning,
131 : Bitmapset *attrs_used,
132 : bool qualify_col,
133 : List **retrieved_attrs);
134 : static void deparseExplicitTargetList(List *tlist,
135 : bool is_returning,
136 : List **retrieved_attrs,
137 : deparse_expr_cxt *context);
138 : static void deparseSubqueryTargetList(deparse_expr_cxt *context);
139 : static void deparseReturningList(StringInfo buf, RangeTblEntry *rte,
140 : Index rtindex, Relation rel,
141 : bool trig_after_row,
142 : List *withCheckOptionList,
143 : List *returningList,
144 : List **retrieved_attrs);
145 : static void deparseColumnRef(StringInfo buf, int varno, int varattno,
146 : RangeTblEntry *rte, bool qualify_col);
147 : static void deparseRelation(StringInfo buf, Relation rel);
148 : static void deparseExpr(Expr *expr, deparse_expr_cxt *context);
149 : static void deparseVar(Var *node, deparse_expr_cxt *context);
150 : static void deparseConst(Const *node, deparse_expr_cxt *context, int showtype);
151 : static void deparseParam(Param *node, deparse_expr_cxt *context);
152 : static void deparseSubscriptingRef(SubscriptingRef *node, deparse_expr_cxt *context);
153 : static void deparseFuncExpr(FuncExpr *node, deparse_expr_cxt *context);
154 : static void deparseOpExpr(OpExpr *node, deparse_expr_cxt *context);
155 : static void deparseOperatorName(StringInfo buf, Form_pg_operator opform);
156 : static void deparseDistinctExpr(DistinctExpr *node, deparse_expr_cxt *context);
157 : static void deparseScalarArrayOpExpr(ScalarArrayOpExpr *node,
158 : deparse_expr_cxt *context);
159 : static void deparseRelabelType(RelabelType *node, deparse_expr_cxt *context);
160 : static void deparseBoolExpr(BoolExpr *node, deparse_expr_cxt *context);
161 : static void deparseNullTest(NullTest *node, deparse_expr_cxt *context);
162 : static void deparseArrayExpr(ArrayExpr *node, deparse_expr_cxt *context);
163 : static void printRemoteParam(int paramindex, Oid paramtype, int32 paramtypmod,
164 : deparse_expr_cxt *context);
165 : static void printRemotePlaceholder(Oid paramtype, int32 paramtypmod,
166 : deparse_expr_cxt *context);
167 : static void deparseSelectSql(List *tlist, bool is_subquery, List **retrieved_attrs,
168 : deparse_expr_cxt *context);
169 : static void deparseLockingClause(deparse_expr_cxt *context);
170 : static void appendOrderByClause(List *pathkeys, bool has_final_sort,
171 : deparse_expr_cxt *context);
172 : static void appendLimitClause(deparse_expr_cxt *context);
173 : static void appendConditions(List *exprs, deparse_expr_cxt *context);
174 : static void deparseFromExprForRel(StringInfo buf, PlannerInfo *root,
175 : RelOptInfo *foreignrel, bool use_alias,
176 : Index ignore_rel, List **ignore_conds,
177 : List **params_list);
178 : static void deparseFromExpr(List *quals, deparse_expr_cxt *context);
179 : static void deparseRangeTblRef(StringInfo buf, PlannerInfo *root,
180 : RelOptInfo *foreignrel, bool make_subquery,
181 : Index ignore_rel, List **ignore_conds, List **params_list);
182 : static void deparseAggref(Aggref *node, deparse_expr_cxt *context);
183 : static void appendGroupByClause(List *tlist, deparse_expr_cxt *context);
184 : static void appendAggOrderBy(List *orderList, List *targetList,
185 : deparse_expr_cxt *context);
186 : static void appendFunctionName(Oid funcid, deparse_expr_cxt *context);
187 : static Node *deparseSortGroupClause(Index ref, List *tlist, bool force_colno,
188 : deparse_expr_cxt *context);
189 :
190 : /*
191 : * Helper functions
192 : */
193 : static bool is_subquery_var(Var *node, RelOptInfo *foreignrel,
194 : int *relno, int *colno);
195 : static void get_relation_column_alias_ids(Var *node, RelOptInfo *foreignrel,
196 : int *relno, int *colno);
197 :
198 :
199 : /*
200 : * Examine each qual clause in input_conds, and classify them into two groups,
201 : * which are returned as two lists:
202 : * - remote_conds contains expressions that can be evaluated remotely
203 : * - local_conds contains expressions that can't be evaluated remotely
204 : */
205 : void
206 3444 : classifyConditions(PlannerInfo *root,
207 : RelOptInfo *baserel,
208 : List *input_conds,
209 : List **remote_conds,
210 : List **local_conds)
211 : {
212 : ListCell *lc;
213 :
214 3444 : *remote_conds = NIL;
215 3444 : *local_conds = NIL;
216 :
217 4520 : foreach(lc, input_conds)
218 : {
219 1076 : RestrictInfo *ri = lfirst_node(RestrictInfo, lc);
220 :
221 1076 : if (is_foreign_expr(root, baserel, ri->clause))
222 1000 : *remote_conds = lappend(*remote_conds, ri);
223 : else
224 76 : *local_conds = lappend(*local_conds, ri);
225 : }
226 3444 : }
227 :
228 : /*
229 : * Returns true if given expr is safe to evaluate on the foreign server.
230 : */
231 : bool
232 4352 : is_foreign_expr(PlannerInfo *root,
233 : RelOptInfo *baserel,
234 : Expr *expr)
235 : {
236 : foreign_glob_cxt glob_cxt;
237 : foreign_loc_cxt loc_cxt;
238 4352 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) (baserel->fdw_private);
239 :
240 : /*
241 : * Check that the expression consists of nodes that are safe to execute
242 : * remotely.
243 : */
244 4352 : glob_cxt.root = root;
245 4352 : glob_cxt.foreignrel = baserel;
246 :
247 : /*
248 : * For an upper relation, use relids from its underneath scan relation,
249 : * because the upperrel's own relids currently aren't set to anything
250 : * meaningful by the core code. For other relation, use their own relids.
251 : */
252 4352 : if (IS_UPPER_REL(baserel))
253 742 : glob_cxt.relids = fpinfo->outerrel->relids;
254 : else
255 3610 : glob_cxt.relids = baserel->relids;
256 4352 : loc_cxt.collation = InvalidOid;
257 4352 : loc_cxt.state = FDW_COLLATE_NONE;
258 4352 : if (!foreign_expr_walker((Node *) expr, &glob_cxt, &loc_cxt))
259 204 : return false;
260 :
261 : /*
262 : * If the expression has a valid collation that does not arise from a
263 : * foreign var, the expression can not be sent over.
264 : */
265 4148 : if (loc_cxt.state == FDW_COLLATE_UNSAFE)
266 4 : return false;
267 :
268 : /*
269 : * An expression which includes any mutable functions can't be sent over
270 : * because its result is not stable. For example, sending now() remote
271 : * side could cause confusion from clock offsets. Future versions might
272 : * be able to make this choice with more granularity. (We check this last
273 : * because it requires a lot of expensive catalog lookups.)
274 : */
275 4144 : if (contain_mutable_functions((Node *) expr))
276 42 : return false;
277 :
278 : /* OK to evaluate on the remote server */
279 4102 : return true;
280 : }
281 :
282 : /*
283 : * Check if expression is safe to execute remotely, and return true if so.
284 : *
285 : * In addition, *outer_cxt is updated with collation information.
286 : *
287 : * We must check that the expression contains only node types we can deparse,
288 : * that all types/functions/operators are safe to send (they are "shippable"),
289 : * and that all collations used in the expression derive from Vars of the
290 : * foreign table. Because of the latter, the logic is pretty close to
291 : * assign_collations_walker() in parse_collate.c, though we can assume here
292 : * that the given expression is valid. Note function mutability is not
293 : * currently considered here.
294 : */
295 : static bool
296 12668 : foreign_expr_walker(Node *node,
297 : foreign_glob_cxt *glob_cxt,
298 : foreign_loc_cxt *outer_cxt)
299 : {
300 12668 : bool check_type = true;
301 : PgFdwRelationInfo *fpinfo;
302 : foreign_loc_cxt inner_cxt;
303 : Oid collation;
304 : FDWCollateState state;
305 :
306 : /* Need do nothing for empty subexpressions */
307 12668 : if (node == NULL)
308 470 : return true;
309 :
310 : /* May need server info from baserel's fdw_private struct */
311 12198 : fpinfo = (PgFdwRelationInfo *) (glob_cxt->foreignrel->fdw_private);
312 :
313 : /* Set up inner_cxt for possible recursion to child nodes */
314 12198 : inner_cxt.collation = InvalidOid;
315 12198 : inner_cxt.state = FDW_COLLATE_NONE;
316 :
317 12198 : switch (nodeTag(node))
318 : {
319 : case T_Var:
320 : {
321 4974 : Var *var = (Var *) node;
322 :
323 : /*
324 : * If the Var is from the foreign table, we consider its
325 : * collation (if any) safe to use. If it is from another
326 : * table, we treat its collation the same way as we would a
327 : * Param's collation, ie it's not safe for it to have a
328 : * non-default collation.
329 : */
330 9356 : if (bms_is_member(var->varno, glob_cxt->relids) &&
331 4382 : var->varlevelsup == 0)
332 : {
333 : /* Var belongs to foreign table */
334 :
335 : /*
336 : * System columns other than ctid should not be sent to
337 : * the remote, since we don't make any effort to ensure
338 : * that local and remote values match (tableoid, in
339 : * particular, almost certainly doesn't match).
340 : */
341 4398 : if (var->varattno < 0 &&
342 16 : var->varattno != SelfItemPointerAttributeNumber)
343 12 : return false;
344 :
345 : /* Else check the collation */
346 4370 : collation = var->varcollid;
347 4370 : state = OidIsValid(collation) ? FDW_COLLATE_SAFE : FDW_COLLATE_NONE;
348 : }
349 : else
350 : {
351 : /* Var belongs to some other table */
352 592 : collation = var->varcollid;
353 592 : if (collation == InvalidOid ||
354 : collation == DEFAULT_COLLATION_OID)
355 : {
356 : /*
357 : * It's noncollatable, or it's safe to combine with a
358 : * collatable foreign Var, so set state to NONE.
359 : */
360 592 : state = FDW_COLLATE_NONE;
361 : }
362 : else
363 : {
364 : /*
365 : * Do not fail right away, since the Var might appear
366 : * in a collation-insensitive context.
367 : */
368 0 : state = FDW_COLLATE_UNSAFE;
369 : }
370 : }
371 : }
372 4962 : break;
373 : case T_Const:
374 : {
375 1412 : Const *c = (Const *) node;
376 :
377 : /*
378 : * If the constant has nondefault collation, either it's of a
379 : * non-builtin type, or it reflects folding of a CollateExpr.
380 : * It's unsafe to send to the remote unless it's used in a
381 : * non-collation-sensitive context.
382 : */
383 1412 : collation = c->constcollid;
384 1412 : if (collation == InvalidOid ||
385 : collation == DEFAULT_COLLATION_OID)
386 1408 : state = FDW_COLLATE_NONE;
387 : else
388 4 : state = FDW_COLLATE_UNSAFE;
389 : }
390 1412 : break;
391 : case T_Param:
392 : {
393 34 : Param *p = (Param *) node;
394 :
395 : /*
396 : * Collation rule is same as for Consts and non-foreign Vars.
397 : */
398 34 : collation = p->paramcollid;
399 34 : if (collation == InvalidOid ||
400 : collation == DEFAULT_COLLATION_OID)
401 34 : state = FDW_COLLATE_NONE;
402 : else
403 0 : state = FDW_COLLATE_UNSAFE;
404 : }
405 34 : break;
406 : case T_SubscriptingRef:
407 : {
408 2 : SubscriptingRef *sr = (SubscriptingRef *) node;
409 :
410 : /* Assignment should not be in restrictions. */
411 2 : if (sr->refassgnexpr != NULL)
412 0 : return false;
413 :
414 : /*
415 : * Recurse to remaining subexpressions. Since the container
416 : * subscripts must yield (noncollatable) integers, they won't
417 : * affect the inner_cxt state.
418 : */
419 2 : if (!foreign_expr_walker((Node *) sr->refupperindexpr,
420 : glob_cxt, &inner_cxt))
421 0 : return false;
422 2 : if (!foreign_expr_walker((Node *) sr->reflowerindexpr,
423 : glob_cxt, &inner_cxt))
424 0 : return false;
425 2 : if (!foreign_expr_walker((Node *) sr->refexpr,
426 : glob_cxt, &inner_cxt))
427 0 : return false;
428 :
429 : /*
430 : * Container subscripting should yield same collation as
431 : * input, but for safety use same logic as for function nodes.
432 : */
433 2 : collation = sr->refcollid;
434 2 : if (collation == InvalidOid)
435 2 : state = FDW_COLLATE_NONE;
436 0 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
437 0 : collation == inner_cxt.collation)
438 0 : state = FDW_COLLATE_SAFE;
439 0 : else if (collation == DEFAULT_COLLATION_OID)
440 0 : state = FDW_COLLATE_NONE;
441 : else
442 0 : state = FDW_COLLATE_UNSAFE;
443 : }
444 2 : break;
445 : case T_FuncExpr:
446 : {
447 212 : FuncExpr *fe = (FuncExpr *) node;
448 :
449 : /*
450 : * If function used by the expression is not shippable, it
451 : * can't be sent to remote because it might have incompatible
452 : * semantics on remote side.
453 : */
454 212 : if (!is_shippable(fe->funcid, ProcedureRelationId, fpinfo))
455 10 : return false;
456 :
457 : /*
458 : * Recurse to input subexpressions.
459 : */
460 202 : if (!foreign_expr_walker((Node *) fe->args,
461 : glob_cxt, &inner_cxt))
462 12 : return false;
463 :
464 : /*
465 : * If function's input collation is not derived from a foreign
466 : * Var, it can't be sent to remote.
467 : */
468 190 : if (fe->inputcollid == InvalidOid)
469 : /* OK, inputs are all noncollatable */ ;
470 68 : else if (inner_cxt.state != FDW_COLLATE_SAFE ||
471 24 : fe->inputcollid != inner_cxt.collation)
472 20 : return false;
473 :
474 : /*
475 : * Detect whether node is introducing a collation not derived
476 : * from a foreign Var. (If so, we just mark it unsafe for now
477 : * rather than immediately returning false, since the parent
478 : * node might not care.)
479 : */
480 170 : collation = fe->funccollid;
481 170 : if (collation == InvalidOid)
482 146 : state = FDW_COLLATE_NONE;
483 48 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
484 24 : collation == inner_cxt.collation)
485 24 : state = FDW_COLLATE_SAFE;
486 0 : else if (collation == DEFAULT_COLLATION_OID)
487 0 : state = FDW_COLLATE_NONE;
488 : else
489 0 : state = FDW_COLLATE_UNSAFE;
490 : }
491 170 : break;
492 : case T_OpExpr:
493 : case T_DistinctExpr: /* struct-equivalent to OpExpr */
494 : {
495 2278 : OpExpr *oe = (OpExpr *) node;
496 :
497 : /*
498 : * Similarly, only shippable operators can be sent to remote.
499 : * (If the operator is shippable, we assume its underlying
500 : * function is too.)
501 : */
502 2278 : if (!is_shippable(oe->opno, OperatorRelationId, fpinfo))
503 26 : return false;
504 :
505 : /*
506 : * Recurse to input subexpressions.
507 : */
508 2252 : if (!foreign_expr_walker((Node *) oe->args,
509 : glob_cxt, &inner_cxt))
510 76 : return false;
511 :
512 : /*
513 : * If operator's input collation is not derived from a foreign
514 : * Var, it can't be sent to remote.
515 : */
516 2176 : if (oe->inputcollid == InvalidOid)
517 : /* OK, inputs are all noncollatable */ ;
518 198 : else if (inner_cxt.state != FDW_COLLATE_SAFE ||
519 94 : oe->inputcollid != inner_cxt.collation)
520 10 : return false;
521 :
522 : /* Result-collation handling is same as for functions */
523 2166 : collation = oe->opcollid;
524 2166 : if (collation == InvalidOid)
525 2150 : state = FDW_COLLATE_NONE;
526 32 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
527 16 : collation == inner_cxt.collation)
528 16 : state = FDW_COLLATE_SAFE;
529 0 : else if (collation == DEFAULT_COLLATION_OID)
530 0 : state = FDW_COLLATE_NONE;
531 : else
532 0 : state = FDW_COLLATE_UNSAFE;
533 : }
534 2166 : break;
535 : case T_ScalarArrayOpExpr:
536 : {
537 6 : ScalarArrayOpExpr *oe = (ScalarArrayOpExpr *) node;
538 :
539 : /*
540 : * Again, only shippable operators can be sent to remote.
541 : */
542 6 : if (!is_shippable(oe->opno, OperatorRelationId, fpinfo))
543 0 : return false;
544 :
545 : /*
546 : * Recurse to input subexpressions.
547 : */
548 6 : if (!foreign_expr_walker((Node *) oe->args,
549 : glob_cxt, &inner_cxt))
550 0 : return false;
551 :
552 : /*
553 : * If operator's input collation is not derived from a foreign
554 : * Var, it can't be sent to remote.
555 : */
556 6 : if (oe->inputcollid == InvalidOid)
557 : /* OK, inputs are all noncollatable */ ;
558 0 : else if (inner_cxt.state != FDW_COLLATE_SAFE ||
559 0 : oe->inputcollid != inner_cxt.collation)
560 0 : return false;
561 :
562 : /* Output is always boolean and so noncollatable. */
563 6 : collation = InvalidOid;
564 6 : state = FDW_COLLATE_NONE;
565 : }
566 6 : break;
567 : case T_RelabelType:
568 : {
569 82 : RelabelType *r = (RelabelType *) node;
570 :
571 : /*
572 : * Recurse to input subexpression.
573 : */
574 82 : if (!foreign_expr_walker((Node *) r->arg,
575 : glob_cxt, &inner_cxt))
576 0 : return false;
577 :
578 : /*
579 : * RelabelType must not introduce a collation not derived from
580 : * an input foreign Var (same logic as for a real function).
581 : */
582 82 : collation = r->resultcollid;
583 82 : if (collation == InvalidOid)
584 0 : state = FDW_COLLATE_NONE;
585 156 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
586 74 : collation == inner_cxt.collation)
587 64 : state = FDW_COLLATE_SAFE;
588 18 : else if (collation == DEFAULT_COLLATION_OID)
589 6 : state = FDW_COLLATE_NONE;
590 : else
591 12 : state = FDW_COLLATE_UNSAFE;
592 : }
593 82 : break;
594 : case T_BoolExpr:
595 : {
596 72 : BoolExpr *b = (BoolExpr *) node;
597 :
598 : /*
599 : * Recurse to input subexpressions.
600 : */
601 72 : if (!foreign_expr_walker((Node *) b->args,
602 : glob_cxt, &inner_cxt))
603 0 : return false;
604 :
605 : /* Output is always boolean and so noncollatable. */
606 72 : collation = InvalidOid;
607 72 : state = FDW_COLLATE_NONE;
608 : }
609 72 : break;
610 : case T_NullTest:
611 : {
612 54 : NullTest *nt = (NullTest *) node;
613 :
614 : /*
615 : * Recurse to input subexpressions.
616 : */
617 54 : if (!foreign_expr_walker((Node *) nt->arg,
618 : glob_cxt, &inner_cxt))
619 0 : return false;
620 :
621 : /* Output is always boolean and so noncollatable. */
622 54 : collation = InvalidOid;
623 54 : state = FDW_COLLATE_NONE;
624 : }
625 54 : break;
626 : case T_ArrayExpr:
627 : {
628 8 : ArrayExpr *a = (ArrayExpr *) node;
629 :
630 : /*
631 : * Recurse to input subexpressions.
632 : */
633 8 : if (!foreign_expr_walker((Node *) a->elements,
634 : glob_cxt, &inner_cxt))
635 0 : return false;
636 :
637 : /*
638 : * ArrayExpr must not introduce a collation not derived from
639 : * an input foreign Var (same logic as for a function).
640 : */
641 8 : collation = a->array_collid;
642 8 : if (collation == InvalidOid)
643 8 : state = FDW_COLLATE_NONE;
644 0 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
645 0 : collation == inner_cxt.collation)
646 0 : state = FDW_COLLATE_SAFE;
647 0 : else if (collation == DEFAULT_COLLATION_OID)
648 0 : state = FDW_COLLATE_NONE;
649 : else
650 0 : state = FDW_COLLATE_UNSAFE;
651 : }
652 8 : break;
653 : case T_List:
654 : {
655 2548 : List *l = (List *) node;
656 : ListCell *lc;
657 :
658 : /*
659 : * Recurse to component subexpressions.
660 : */
661 7250 : foreach(lc, l)
662 : {
663 4816 : if (!foreign_expr_walker((Node *) lfirst(lc),
664 : glob_cxt, &inner_cxt))
665 114 : return false;
666 : }
667 :
668 : /*
669 : * When processing a list, collation state just bubbles up
670 : * from the list elements.
671 : */
672 2434 : collation = inner_cxt.collation;
673 2434 : state = inner_cxt.state;
674 :
675 : /* Don't apply exprType() to the list. */
676 2434 : check_type = false;
677 : }
678 2434 : break;
679 : case T_Aggref:
680 : {
681 456 : Aggref *agg = (Aggref *) node;
682 : ListCell *lc;
683 :
684 : /* Not safe to pushdown when not in grouping context */
685 456 : if (!IS_UPPER_REL(glob_cxt->foreignrel))
686 0 : return false;
687 :
688 : /* Only non-split aggregates are pushable. */
689 456 : if (agg->aggsplit != AGGSPLIT_SIMPLE)
690 0 : return false;
691 :
692 : /* As usual, it must be shippable. */
693 456 : if (!is_shippable(agg->aggfnoid, ProcedureRelationId, fpinfo))
694 8 : return false;
695 :
696 : /*
697 : * Recurse to input args. aggdirectargs, aggorder and
698 : * aggdistinct are all present in args, so no need to check
699 : * their shippability explicitly.
700 : */
701 826 : foreach(lc, agg->args)
702 : {
703 402 : Node *n = (Node *) lfirst(lc);
704 :
705 : /* If TargetEntry, extract the expression from it */
706 402 : if (IsA(n, TargetEntry))
707 : {
708 402 : TargetEntry *tle = (TargetEntry *) n;
709 :
710 402 : n = (Node *) tle->expr;
711 : }
712 :
713 402 : if (!foreign_expr_walker(n, glob_cxt, &inner_cxt))
714 24 : return false;
715 : }
716 :
717 : /*
718 : * For aggorder elements, check whether the sort operator, if
719 : * specified, is shippable or not.
720 : */
721 424 : if (agg->aggorder)
722 : {
723 : ListCell *lc;
724 :
725 116 : foreach(lc, agg->aggorder)
726 : {
727 64 : SortGroupClause *srt = (SortGroupClause *) lfirst(lc);
728 : Oid sortcoltype;
729 : TypeCacheEntry *typentry;
730 : TargetEntry *tle;
731 :
732 64 : tle = get_sortgroupref_tle(srt->tleSortGroupRef,
733 : agg->args);
734 64 : sortcoltype = exprType((Node *) tle->expr);
735 64 : typentry = lookup_type_cache(sortcoltype,
736 : TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
737 : /* Check shippability of non-default sort operator. */
738 88 : if (srt->sortop != typentry->lt_opr &&
739 36 : srt->sortop != typentry->gt_opr &&
740 12 : !is_shippable(srt->sortop, OperatorRelationId,
741 : fpinfo))
742 8 : return false;
743 : }
744 : }
745 :
746 : /* Check aggregate filter */
747 416 : if (!foreign_expr_walker((Node *) agg->aggfilter,
748 : glob_cxt, &inner_cxt))
749 4 : return false;
750 :
751 : /*
752 : * If aggregate's input collation is not derived from a
753 : * foreign Var, it can't be sent to remote.
754 : */
755 412 : if (agg->inputcollid == InvalidOid)
756 : /* OK, inputs are all noncollatable */ ;
757 72 : else if (inner_cxt.state != FDW_COLLATE_SAFE ||
758 36 : agg->inputcollid != inner_cxt.collation)
759 0 : return false;
760 :
761 : /*
762 : * Detect whether node is introducing a collation not derived
763 : * from a foreign Var. (If so, we just mark it unsafe for now
764 : * rather than immediately returning false, since the parent
765 : * node might not care.)
766 : */
767 412 : collation = agg->aggcollid;
768 412 : if (collation == InvalidOid)
769 410 : state = FDW_COLLATE_NONE;
770 4 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
771 2 : collation == inner_cxt.collation)
772 2 : state = FDW_COLLATE_SAFE;
773 0 : else if (collation == DEFAULT_COLLATION_OID)
774 0 : state = FDW_COLLATE_NONE;
775 : else
776 0 : state = FDW_COLLATE_UNSAFE;
777 : }
778 412 : break;
779 : default:
780 :
781 : /*
782 : * If it's anything else, assume it's unsafe. This list can be
783 : * expanded later, but don't forget to add deparse support below.
784 : */
785 60 : return false;
786 : }
787 :
788 : /*
789 : * If result type of given expression is not shippable, it can't be sent
790 : * to remote because it might have incompatible semantics on remote side.
791 : */
792 11814 : if (check_type && !is_shippable(exprType(node), TypeRelationId, fpinfo))
793 50 : return false;
794 :
795 : /*
796 : * Now, merge my collation information into my parent's state.
797 : */
798 11764 : if (state > outer_cxt->state)
799 : {
800 : /* Override previous parent state */
801 574 : outer_cxt->collation = collation;
802 574 : outer_cxt->state = state;
803 : }
804 11190 : else if (state == outer_cxt->state)
805 : {
806 : /* Merge, or detect error if there's a collation conflict */
807 11114 : switch (state)
808 : {
809 : case FDW_COLLATE_NONE:
810 : /* Nothing + nothing is still nothing */
811 11108 : break;
812 : case FDW_COLLATE_SAFE:
813 4 : if (collation != outer_cxt->collation)
814 : {
815 : /*
816 : * Non-default collation always beats default.
817 : */
818 0 : if (outer_cxt->collation == DEFAULT_COLLATION_OID)
819 : {
820 : /* Override previous parent state */
821 0 : outer_cxt->collation = collation;
822 : }
823 0 : else if (collation != DEFAULT_COLLATION_OID)
824 : {
825 : /*
826 : * Conflict; show state as indeterminate. We don't
827 : * want to "return false" right away, since parent
828 : * node might not care about collation.
829 : */
830 0 : outer_cxt->state = FDW_COLLATE_UNSAFE;
831 : }
832 : }
833 4 : break;
834 : case FDW_COLLATE_UNSAFE:
835 : /* We're still conflicted ... */
836 2 : break;
837 : }
838 : }
839 :
840 : /* It looks OK */
841 11764 : return true;
842 : }
843 :
844 : /*
845 : * Returns true if given expr is something we'd have to send the value of
846 : * to the foreign server.
847 : *
848 : * This should return true when the expression is a shippable node that
849 : * deparseExpr would add to context->params_list. Note that we don't care
850 : * if the expression *contains* such a node, only whether one appears at top
851 : * level. We need this to detect cases where setrefs.c would recognize a
852 : * false match between an fdw_exprs item (which came from the params_list)
853 : * and an entry in fdw_scan_tlist (which we're considering putting the given
854 : * expression into).
855 : */
856 : bool
857 500 : is_foreign_param(PlannerInfo *root,
858 : RelOptInfo *baserel,
859 : Expr *expr)
860 : {
861 500 : if (expr == NULL)
862 0 : return false;
863 :
864 500 : switch (nodeTag(expr))
865 : {
866 : case T_Var:
867 : {
868 : /* It would have to be sent unless it's a foreign Var */
869 152 : Var *var = (Var *) expr;
870 152 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) (baserel->fdw_private);
871 : Relids relids;
872 :
873 152 : if (IS_UPPER_REL(baserel))
874 152 : relids = fpinfo->outerrel->relids;
875 : else
876 0 : relids = baserel->relids;
877 :
878 152 : if (bms_is_member(var->varno, relids) && var->varlevelsup == 0)
879 152 : return false; /* foreign Var, so not a param */
880 : else
881 0 : return true; /* it'd have to be a param */
882 : break;
883 : }
884 : case T_Param:
885 : /* Params always have to be sent to the foreign server */
886 8 : return true;
887 : default:
888 340 : break;
889 : }
890 340 : return false;
891 : }
892 :
893 : /*
894 : * Convert type OID + typmod info into a type name we can ship to the remote
895 : * server. Someplace else had better have verified that this type name is
896 : * expected to be known on the remote end.
897 : *
898 : * This is almost just format_type_with_typemod(), except that if left to its
899 : * own devices, that function will make schema-qualification decisions based
900 : * on the local search_path, which is wrong. We must schema-qualify all
901 : * type names that are not in pg_catalog. We assume here that built-in types
902 : * are all in pg_catalog and need not be qualified; otherwise, qualify.
903 : */
904 : static char *
905 826 : deparse_type_name(Oid type_oid, int32 typemod)
906 : {
907 826 : bits16 flags = FORMAT_TYPE_TYPEMOD_GIVEN;
908 :
909 826 : if (!is_builtin(type_oid))
910 0 : flags |= FORMAT_TYPE_FORCE_QUALIFY;
911 :
912 826 : return format_type_extended(type_oid, typemod, flags);
913 : }
914 :
915 : /*
916 : * Build the targetlist for given relation to be deparsed as SELECT clause.
917 : *
918 : * The output targetlist contains the columns that need to be fetched from the
919 : * foreign server for the given relation. If foreignrel is an upper relation,
920 : * then the output targetlist can also contain expressions to be evaluated on
921 : * foreign server.
922 : */
923 : List *
924 1032 : build_tlist_to_deparse(RelOptInfo *foreignrel)
925 : {
926 1032 : List *tlist = NIL;
927 1032 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
928 : ListCell *lc;
929 :
930 : /*
931 : * For an upper relation, we have already built the target list while
932 : * checking shippability, so just return that.
933 : */
934 1032 : if (IS_UPPER_REL(foreignrel))
935 278 : return fpinfo->grouped_tlist;
936 :
937 : /*
938 : * We require columns specified in foreignrel->reltarget->exprs and those
939 : * required for evaluating the local conditions.
940 : */
941 754 : tlist = add_to_flat_tlist(tlist,
942 754 : pull_var_clause((Node *) foreignrel->reltarget->exprs,
943 : PVC_RECURSE_PLACEHOLDERS));
944 790 : foreach(lc, fpinfo->local_conds)
945 : {
946 36 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
947 :
948 36 : tlist = add_to_flat_tlist(tlist,
949 36 : pull_var_clause((Node *) rinfo->clause,
950 : PVC_RECURSE_PLACEHOLDERS));
951 : }
952 :
953 754 : return tlist;
954 : }
955 :
956 : /*
957 : * Deparse SELECT statement for given relation into buf.
958 : *
959 : * tlist contains the list of desired columns to be fetched from foreign server.
960 : * For a base relation fpinfo->attrs_used is used to construct SELECT clause,
961 : * hence the tlist is ignored for a base relation.
962 : *
963 : * remote_conds is the list of conditions to be deparsed into the WHERE clause
964 : * (or, in the case of upper relations, into the HAVING clause).
965 : *
966 : * If params_list is not NULL, it receives a list of Params and other-relation
967 : * Vars used in the clauses; these values must be transmitted to the remote
968 : * server as parameter values.
969 : *
970 : * If params_list is NULL, we're generating the query for EXPLAIN purposes,
971 : * so Params and other-relation Vars should be replaced by dummy values.
972 : *
973 : * pathkeys is the list of pathkeys to order the result by.
974 : *
975 : * is_subquery is the flag to indicate whether to deparse the specified
976 : * relation as a subquery.
977 : *
978 : * List of columns selected is returned in retrieved_attrs.
979 : */
980 : void
981 3136 : deparseSelectStmtForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *rel,
982 : List *tlist, List *remote_conds, List *pathkeys,
983 : bool has_final_sort, bool has_limit, bool is_subquery,
984 : List **retrieved_attrs, List **params_list)
985 : {
986 : deparse_expr_cxt context;
987 3136 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private;
988 : List *quals;
989 :
990 : /*
991 : * We handle relations for foreign tables, joins between those and upper
992 : * relations.
993 : */
994 : Assert(IS_JOIN_REL(rel) || IS_SIMPLE_REL(rel) || IS_UPPER_REL(rel));
995 :
996 : /* Fill portions of context common to upper, join and base relation */
997 3136 : context.buf = buf;
998 3136 : context.root = root;
999 3136 : context.foreignrel = rel;
1000 3136 : context.scanrel = IS_UPPER_REL(rel) ? fpinfo->outerrel : rel;
1001 3136 : context.params_list = params_list;
1002 :
1003 : /* Construct SELECT clause */
1004 3136 : deparseSelectSql(tlist, is_subquery, retrieved_attrs, &context);
1005 :
1006 : /*
1007 : * For upper relations, the WHERE clause is built from the remote
1008 : * conditions of the underlying scan relation; otherwise, we can use the
1009 : * supplied list of remote conditions directly.
1010 : */
1011 3136 : if (IS_UPPER_REL(rel))
1012 278 : {
1013 : PgFdwRelationInfo *ofpinfo;
1014 :
1015 278 : ofpinfo = (PgFdwRelationInfo *) fpinfo->outerrel->fdw_private;
1016 278 : quals = ofpinfo->remote_conds;
1017 : }
1018 : else
1019 2858 : quals = remote_conds;
1020 :
1021 : /* Construct FROM and WHERE clauses */
1022 3136 : deparseFromExpr(quals, &context);
1023 :
1024 3136 : if (IS_UPPER_REL(rel))
1025 : {
1026 : /* Append GROUP BY clause */
1027 278 : appendGroupByClause(tlist, &context);
1028 :
1029 : /* Append HAVING clause */
1030 278 : if (remote_conds)
1031 : {
1032 36 : appendStringInfoString(buf, " HAVING ");
1033 36 : appendConditions(remote_conds, &context);
1034 : }
1035 : }
1036 :
1037 : /* Add ORDER BY clause if we found any useful pathkeys */
1038 3136 : if (pathkeys)
1039 922 : appendOrderByClause(pathkeys, has_final_sort, &context);
1040 :
1041 : /* Add LIMIT clause if necessary */
1042 3136 : if (has_limit)
1043 178 : appendLimitClause(&context);
1044 :
1045 : /* Add any necessary FOR UPDATE/SHARE. */
1046 3136 : deparseLockingClause(&context);
1047 3136 : }
1048 :
1049 : /*
1050 : * Construct a simple SELECT statement that retrieves desired columns
1051 : * of the specified foreign table, and append it to "buf". The output
1052 : * contains just "SELECT ... ".
1053 : *
1054 : * We also create an integer List of the columns being retrieved, which is
1055 : * returned to *retrieved_attrs, unless we deparse the specified relation
1056 : * as a subquery.
1057 : *
1058 : * tlist is the list of desired columns. is_subquery is the flag to
1059 : * indicate whether to deparse the specified relation as a subquery.
1060 : * Read prologue of deparseSelectStmtForRel() for details.
1061 : */
1062 : static void
1063 3136 : deparseSelectSql(List *tlist, bool is_subquery, List **retrieved_attrs,
1064 : deparse_expr_cxt *context)
1065 : {
1066 3136 : StringInfo buf = context->buf;
1067 3136 : RelOptInfo *foreignrel = context->foreignrel;
1068 3136 : PlannerInfo *root = context->root;
1069 3136 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
1070 :
1071 : /*
1072 : * Construct SELECT list
1073 : */
1074 3136 : appendStringInfoString(buf, "SELECT ");
1075 :
1076 3136 : if (is_subquery)
1077 : {
1078 : /*
1079 : * For a relation that is deparsed as a subquery, emit expressions
1080 : * specified in the relation's reltarget. Note that since this is for
1081 : * the subquery, no need to care about *retrieved_attrs.
1082 : */
1083 56 : deparseSubqueryTargetList(context);
1084 : }
1085 3080 : else if (IS_JOIN_REL(foreignrel) || IS_UPPER_REL(foreignrel))
1086 : {
1087 : /*
1088 : * For a join or upper relation the input tlist gives the list of
1089 : * columns required to be fetched from the foreign server.
1090 : */
1091 1032 : deparseExplicitTargetList(tlist, false, retrieved_attrs, context);
1092 : }
1093 : else
1094 : {
1095 : /*
1096 : * For a base relation fpinfo->attrs_used gives the list of columns
1097 : * required to be fetched from the foreign server.
1098 : */
1099 2048 : RangeTblEntry *rte = planner_rt_fetch(foreignrel->relid, root);
1100 :
1101 : /*
1102 : * Core code already has some lock on each rel being planned, so we
1103 : * can use NoLock here.
1104 : */
1105 2048 : Relation rel = table_open(rte->relid, NoLock);
1106 :
1107 2048 : deparseTargetList(buf, rte, foreignrel->relid, rel, false,
1108 : fpinfo->attrs_used, false, retrieved_attrs);
1109 2048 : table_close(rel, NoLock);
1110 : }
1111 3136 : }
1112 :
1113 : /*
1114 : * Construct a FROM clause and, if needed, a WHERE clause, and append those to
1115 : * "buf".
1116 : *
1117 : * quals is the list of clauses to be included in the WHERE clause.
1118 : * (These may or may not include RestrictInfo decoration.)
1119 : */
1120 : static void
1121 3136 : deparseFromExpr(List *quals, deparse_expr_cxt *context)
1122 : {
1123 3136 : StringInfo buf = context->buf;
1124 3136 : RelOptInfo *scanrel = context->scanrel;
1125 :
1126 : /* For upper relations, scanrel must be either a joinrel or a baserel */
1127 : Assert(!IS_UPPER_REL(context->foreignrel) ||
1128 : IS_JOIN_REL(scanrel) || IS_SIMPLE_REL(scanrel));
1129 :
1130 : /* Construct FROM clause */
1131 3136 : appendStringInfoString(buf, " FROM ");
1132 6272 : deparseFromExprForRel(buf, context->root, scanrel,
1133 3136 : (bms_membership(scanrel->relids) == BMS_MULTIPLE),
1134 : (Index) 0, NULL, context->params_list);
1135 :
1136 : /* Construct WHERE clause */
1137 3136 : if (quals != NIL)
1138 : {
1139 1234 : appendStringInfoString(buf, " WHERE ");
1140 1234 : appendConditions(quals, context);
1141 : }
1142 3136 : }
1143 :
1144 : /*
1145 : * Emit a target list that retrieves the columns specified in attrs_used.
1146 : * This is used for both SELECT and RETURNING targetlists; the is_returning
1147 : * parameter is true only for a RETURNING targetlist.
1148 : *
1149 : * The tlist text is appended to buf, and we also create an integer List
1150 : * of the columns being retrieved, which is returned to *retrieved_attrs.
1151 : *
1152 : * If qualify_col is true, add relation alias before the column name.
1153 : */
1154 : static void
1155 2622 : deparseTargetList(StringInfo buf,
1156 : RangeTblEntry *rte,
1157 : Index rtindex,
1158 : Relation rel,
1159 : bool is_returning,
1160 : Bitmapset *attrs_used,
1161 : bool qualify_col,
1162 : List **retrieved_attrs)
1163 : {
1164 2622 : TupleDesc tupdesc = RelationGetDescr(rel);
1165 : bool have_wholerow;
1166 : bool first;
1167 : int i;
1168 :
1169 2622 : *retrieved_attrs = NIL;
1170 :
1171 : /* If there's a whole-row reference, we'll need all the columns. */
1172 2622 : have_wholerow = bms_is_member(0 - FirstLowInvalidHeapAttributeNumber,
1173 : attrs_used);
1174 :
1175 2622 : first = true;
1176 19058 : for (i = 1; i <= tupdesc->natts; i++)
1177 : {
1178 16436 : Form_pg_attribute attr = TupleDescAttr(tupdesc, i - 1);
1179 :
1180 : /* Ignore dropped attributes. */
1181 16436 : if (attr->attisdropped)
1182 1494 : continue;
1183 :
1184 26036 : if (have_wholerow ||
1185 11094 : bms_is_member(i - FirstLowInvalidHeapAttributeNumber,
1186 : attrs_used))
1187 : {
1188 8642 : if (!first)
1189 6134 : appendStringInfoString(buf, ", ");
1190 2508 : else if (is_returning)
1191 170 : appendStringInfoString(buf, " RETURNING ");
1192 8642 : first = false;
1193 :
1194 8642 : deparseColumnRef(buf, rtindex, i, rte, qualify_col);
1195 :
1196 8642 : *retrieved_attrs = lappend_int(*retrieved_attrs, i);
1197 : }
1198 : }
1199 :
1200 : /*
1201 : * Add ctid if needed. We currently don't support retrieving any other
1202 : * system columns.
1203 : */
1204 2622 : if (bms_is_member(SelfItemPointerAttributeNumber - FirstLowInvalidHeapAttributeNumber,
1205 : attrs_used))
1206 : {
1207 452 : if (!first)
1208 364 : appendStringInfoString(buf, ", ");
1209 88 : else if (is_returning)
1210 0 : appendStringInfoString(buf, " RETURNING ");
1211 452 : first = false;
1212 :
1213 452 : if (qualify_col)
1214 0 : ADD_REL_QUALIFIER(buf, rtindex);
1215 452 : appendStringInfoString(buf, "ctid");
1216 :
1217 452 : *retrieved_attrs = lappend_int(*retrieved_attrs,
1218 : SelfItemPointerAttributeNumber);
1219 : }
1220 :
1221 : /* Don't generate bad syntax if no undropped columns */
1222 2622 : if (first && !is_returning)
1223 14 : appendStringInfoString(buf, "NULL");
1224 2622 : }
1225 :
1226 : /*
1227 : * Deparse the appropriate locking clause (FOR UPDATE or FOR SHARE) for a
1228 : * given relation (context->scanrel).
1229 : */
1230 : static void
1231 3136 : deparseLockingClause(deparse_expr_cxt *context)
1232 : {
1233 3136 : StringInfo buf = context->buf;
1234 3136 : PlannerInfo *root = context->root;
1235 3136 : RelOptInfo *rel = context->scanrel;
1236 3136 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private;
1237 3136 : int relid = -1;
1238 :
1239 10390 : while ((relid = bms_next_member(rel->relids, relid)) >= 0)
1240 : {
1241 : /*
1242 : * Ignore relation if it appears in a lower subquery. Locking clause
1243 : * for such a relation is included in the subquery if necessary.
1244 : */
1245 4118 : if (bms_is_member(relid, fpinfo->lower_subquery_rels))
1246 64 : continue;
1247 :
1248 : /*
1249 : * Add FOR UPDATE/SHARE if appropriate. We apply locking during the
1250 : * initial row fetch, rather than later on as is done for local
1251 : * tables. The extra roundtrips involved in trying to duplicate the
1252 : * local semantics exactly don't seem worthwhile (see also comments
1253 : * for RowMarkType).
1254 : *
1255 : * Note: because we actually run the query as a cursor, this assumes
1256 : * that DECLARE CURSOR ... FOR UPDATE is supported, which it isn't
1257 : * before 8.3.
1258 : */
1259 4508 : if (relid == root->parse->resultRelation &&
1260 648 : (root->parse->commandType == CMD_UPDATE ||
1261 194 : root->parse->commandType == CMD_DELETE))
1262 : {
1263 : /* Relation is UPDATE/DELETE target, so use FOR UPDATE */
1264 454 : appendStringInfoString(buf, " FOR UPDATE");
1265 :
1266 : /* Add the relation alias if we are here for a join relation */
1267 908 : if (IS_JOIN_REL(rel))
1268 84 : appendStringInfo(buf, " OF %s%d", REL_ALIAS_PREFIX, relid);
1269 : }
1270 : else
1271 : {
1272 3600 : PlanRowMark *rc = get_plan_rowmark(root->rowMarks, relid);
1273 :
1274 3600 : if (rc)
1275 : {
1276 : /*
1277 : * Relation is specified as a FOR UPDATE/SHARE target, so
1278 : * handle that. (But we could also see LCS_NONE, meaning this
1279 : * isn't a target relation after all.)
1280 : *
1281 : * For now, just ignore any [NO] KEY specification, since (a)
1282 : * it's not clear what that means for a remote table that we
1283 : * don't have complete information about, and (b) it wouldn't
1284 : * work anyway on older remote servers. Likewise, we don't
1285 : * worry about NOWAIT.
1286 : */
1287 588 : switch (rc->strength)
1288 : {
1289 : case LCS_NONE:
1290 : /* No locking needed */
1291 292 : break;
1292 : case LCS_FORKEYSHARE:
1293 : case LCS_FORSHARE:
1294 68 : appendStringInfoString(buf, " FOR SHARE");
1295 68 : break;
1296 : case LCS_FORNOKEYUPDATE:
1297 : case LCS_FORUPDATE:
1298 228 : appendStringInfoString(buf, " FOR UPDATE");
1299 228 : break;
1300 : }
1301 :
1302 : /* Add the relation alias if we are here for a join relation */
1303 944 : if (bms_membership(rel->relids) == BMS_MULTIPLE &&
1304 356 : rc->strength != LCS_NONE)
1305 208 : appendStringInfo(buf, " OF %s%d", REL_ALIAS_PREFIX, relid);
1306 : }
1307 : }
1308 : }
1309 3136 : }
1310 :
1311 : /*
1312 : * Deparse conditions from the provided list and append them to buf.
1313 : *
1314 : * The conditions in the list are assumed to be ANDed. This function is used to
1315 : * deparse WHERE clauses, JOIN .. ON clauses and HAVING clauses.
1316 : *
1317 : * Depending on the caller, the list elements might be either RestrictInfos
1318 : * or bare clauses.
1319 : */
1320 : static void
1321 2302 : appendConditions(List *exprs, deparse_expr_cxt *context)
1322 : {
1323 : int nestlevel;
1324 : ListCell *lc;
1325 2302 : bool is_first = true;
1326 2302 : StringInfo buf = context->buf;
1327 :
1328 : /* Make sure any constants in the exprs are printed portably */
1329 2302 : nestlevel = set_transmission_modes();
1330 :
1331 5260 : foreach(lc, exprs)
1332 : {
1333 2958 : Expr *expr = (Expr *) lfirst(lc);
1334 :
1335 : /* Extract clause from RestrictInfo, if required */
1336 2958 : if (IsA(expr, RestrictInfo))
1337 2442 : expr = ((RestrictInfo *) expr)->clause;
1338 :
1339 : /* Connect expressions with "AND" and parenthesize each condition. */
1340 2958 : if (!is_first)
1341 656 : appendStringInfoString(buf, " AND ");
1342 :
1343 2958 : appendStringInfoChar(buf, '(');
1344 2958 : deparseExpr(expr, context);
1345 2958 : appendStringInfoChar(buf, ')');
1346 :
1347 2958 : is_first = false;
1348 : }
1349 :
1350 2302 : reset_transmission_modes(nestlevel);
1351 2302 : }
1352 :
1353 : /* Output join name for given join type */
1354 : const char *
1355 1408 : get_jointype_name(JoinType jointype)
1356 : {
1357 1408 : switch (jointype)
1358 : {
1359 : case JOIN_INNER:
1360 828 : return "INNER";
1361 :
1362 : case JOIN_LEFT:
1363 364 : return "LEFT";
1364 :
1365 : case JOIN_RIGHT:
1366 0 : return "RIGHT";
1367 :
1368 : case JOIN_FULL:
1369 216 : return "FULL";
1370 :
1371 : default:
1372 : /* Shouldn't come here, but protect from buggy code. */
1373 0 : elog(ERROR, "unsupported join type %d", jointype);
1374 : }
1375 :
1376 : /* Keep compiler happy */
1377 : return NULL;
1378 : }
1379 :
1380 : /*
1381 : * Deparse given targetlist and append it to context->buf.
1382 : *
1383 : * tlist is list of TargetEntry's which in turn contain Var nodes.
1384 : *
1385 : * retrieved_attrs is the list of continuously increasing integers starting
1386 : * from 1. It has same number of entries as tlist.
1387 : *
1388 : * This is used for both SELECT and RETURNING targetlists; the is_returning
1389 : * parameter is true only for a RETURNING targetlist.
1390 : */
1391 : static void
1392 1056 : deparseExplicitTargetList(List *tlist,
1393 : bool is_returning,
1394 : List **retrieved_attrs,
1395 : deparse_expr_cxt *context)
1396 : {
1397 : ListCell *lc;
1398 1056 : StringInfo buf = context->buf;
1399 1056 : int i = 0;
1400 :
1401 1056 : *retrieved_attrs = NIL;
1402 :
1403 5176 : foreach(lc, tlist)
1404 : {
1405 4120 : TargetEntry *tle = lfirst_node(TargetEntry, lc);
1406 :
1407 4120 : if (i > 0)
1408 3080 : appendStringInfoString(buf, ", ");
1409 1040 : else if (is_returning)
1410 12 : appendStringInfoString(buf, " RETURNING ");
1411 :
1412 4120 : deparseExpr((Expr *) tle->expr, context);
1413 :
1414 4120 : *retrieved_attrs = lappend_int(*retrieved_attrs, i + 1);
1415 4120 : i++;
1416 : }
1417 :
1418 1056 : if (i == 0 && !is_returning)
1419 4 : appendStringInfoString(buf, "NULL");
1420 1056 : }
1421 :
1422 : /*
1423 : * Emit expressions specified in the given relation's reltarget.
1424 : *
1425 : * This is used for deparsing the given relation as a subquery.
1426 : */
1427 : static void
1428 56 : deparseSubqueryTargetList(deparse_expr_cxt *context)
1429 : {
1430 56 : StringInfo buf = context->buf;
1431 56 : RelOptInfo *foreignrel = context->foreignrel;
1432 : bool first;
1433 : ListCell *lc;
1434 :
1435 : /* Should only be called in these cases. */
1436 : Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
1437 :
1438 56 : first = true;
1439 120 : foreach(lc, foreignrel->reltarget->exprs)
1440 : {
1441 64 : Node *node = (Node *) lfirst(lc);
1442 :
1443 64 : if (!first)
1444 16 : appendStringInfoString(buf, ", ");
1445 64 : first = false;
1446 :
1447 64 : deparseExpr((Expr *) node, context);
1448 : }
1449 :
1450 : /* Don't generate bad syntax if no expressions */
1451 56 : if (first)
1452 8 : appendStringInfoString(buf, "NULL");
1453 56 : }
1454 :
1455 : /*
1456 : * Construct FROM clause for given relation
1457 : *
1458 : * The function constructs ... JOIN ... ON ... for join relation. For a base
1459 : * relation it just returns schema-qualified tablename, with the appropriate
1460 : * alias if so requested.
1461 : *
1462 : * 'ignore_rel' is either zero or the RT index of a target relation. In the
1463 : * latter case the function constructs FROM clause of UPDATE or USING clause
1464 : * of DELETE; it deparses the join relation as if the relation never contained
1465 : * the target relation, and creates a List of conditions to be deparsed into
1466 : * the top-level WHERE clause, which is returned to *ignore_conds.
1467 : */
1468 : static void
1469 5092 : deparseFromExprForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *foreignrel,
1470 : bool use_alias, Index ignore_rel, List **ignore_conds,
1471 : List **params_list)
1472 : {
1473 5092 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
1474 :
1475 5092 : if (IS_JOIN_REL(foreignrel))
1476 982 : {
1477 : StringInfoData join_sql_o;
1478 : StringInfoData join_sql_i;
1479 1006 : RelOptInfo *outerrel = fpinfo->outerrel;
1480 1006 : RelOptInfo *innerrel = fpinfo->innerrel;
1481 1006 : bool outerrel_is_target = false;
1482 1006 : bool innerrel_is_target = false;
1483 :
1484 1006 : if (ignore_rel > 0 && bms_is_member(ignore_rel, foreignrel->relids))
1485 : {
1486 : /*
1487 : * If this is an inner join, add joinclauses to *ignore_conds and
1488 : * set it to empty so that those can be deparsed into the WHERE
1489 : * clause. Note that since the target relation can never be
1490 : * within the nullable side of an outer join, those could safely
1491 : * be pulled up into the WHERE clause (see foreign_join_ok()).
1492 : * Note also that since the target relation is only inner-joined
1493 : * to any other relation in the query, all conditions in the join
1494 : * tree mentioning the target relation could be deparsed into the
1495 : * WHERE clause by doing this recursively.
1496 : */
1497 32 : if (fpinfo->jointype == JOIN_INNER)
1498 : {
1499 28 : *ignore_conds = list_concat(*ignore_conds,
1500 28 : fpinfo->joinclauses);
1501 28 : fpinfo->joinclauses = NIL;
1502 : }
1503 :
1504 : /*
1505 : * Check if either of the input relations is the target relation.
1506 : */
1507 32 : if (outerrel->relid == ignore_rel)
1508 24 : outerrel_is_target = true;
1509 8 : else if (innerrel->relid == ignore_rel)
1510 0 : innerrel_is_target = true;
1511 : }
1512 :
1513 : /* Deparse outer relation if not the target relation. */
1514 1006 : if (!outerrel_is_target)
1515 : {
1516 982 : initStringInfo(&join_sql_o);
1517 982 : deparseRangeTblRef(&join_sql_o, root, outerrel,
1518 982 : fpinfo->make_outerrel_subquery,
1519 : ignore_rel, ignore_conds, params_list);
1520 :
1521 : /*
1522 : * If inner relation is the target relation, skip deparsing it.
1523 : * Note that since the join of the target relation with any other
1524 : * relation in the query is an inner join and can never be within
1525 : * the nullable side of an outer join, the join could be
1526 : * interchanged with higher-level joins (cf. identity 1 on outer
1527 : * join reordering shown in src/backend/optimizer/README), which
1528 : * means it's safe to skip the target-relation deparsing here.
1529 : */
1530 982 : if (innerrel_is_target)
1531 : {
1532 : Assert(fpinfo->jointype == JOIN_INNER);
1533 : Assert(fpinfo->joinclauses == NIL);
1534 0 : appendBinaryStringInfo(buf, join_sql_o.data, join_sql_o.len);
1535 0 : return;
1536 : }
1537 : }
1538 :
1539 : /* Deparse inner relation if not the target relation. */
1540 1006 : if (!innerrel_is_target)
1541 : {
1542 1006 : initStringInfo(&join_sql_i);
1543 1006 : deparseRangeTblRef(&join_sql_i, root, innerrel,
1544 1006 : fpinfo->make_innerrel_subquery,
1545 : ignore_rel, ignore_conds, params_list);
1546 :
1547 : /*
1548 : * If outer relation is the target relation, skip deparsing it.
1549 : * See the above note about safety.
1550 : */
1551 1006 : if (outerrel_is_target)
1552 : {
1553 : Assert(fpinfo->jointype == JOIN_INNER);
1554 : Assert(fpinfo->joinclauses == NIL);
1555 24 : appendBinaryStringInfo(buf, join_sql_i.data, join_sql_i.len);
1556 24 : return;
1557 : }
1558 : }
1559 :
1560 : /* Neither of the relations is the target relation. */
1561 : Assert(!outerrel_is_target && !innerrel_is_target);
1562 :
1563 : /*
1564 : * For a join relation FROM clause entry is deparsed as
1565 : *
1566 : * ((outer relation) <join type> (inner relation) ON (joinclauses))
1567 : */
1568 982 : appendStringInfo(buf, "(%s %s JOIN %s ON ", join_sql_o.data,
1569 : get_jointype_name(fpinfo->jointype), join_sql_i.data);
1570 :
1571 : /* Append join clause; (TRUE) if no join clause */
1572 982 : if (fpinfo->joinclauses)
1573 : {
1574 : deparse_expr_cxt context;
1575 :
1576 950 : context.buf = buf;
1577 950 : context.foreignrel = foreignrel;
1578 950 : context.scanrel = foreignrel;
1579 950 : context.root = root;
1580 950 : context.params_list = params_list;
1581 :
1582 950 : appendStringInfoChar(buf, '(');
1583 950 : appendConditions(fpinfo->joinclauses, &context);
1584 950 : appendStringInfoChar(buf, ')');
1585 : }
1586 : else
1587 32 : appendStringInfoString(buf, "(TRUE)");
1588 :
1589 : /* End the FROM clause entry. */
1590 982 : appendStringInfoChar(buf, ')');
1591 : }
1592 : else
1593 : {
1594 4086 : RangeTblEntry *rte = planner_rt_fetch(foreignrel->relid, root);
1595 :
1596 : /*
1597 : * Core code already has some lock on each rel being planned, so we
1598 : * can use NoLock here.
1599 : */
1600 4086 : Relation rel = table_open(rte->relid, NoLock);
1601 :
1602 4086 : deparseRelation(buf, rel);
1603 :
1604 : /*
1605 : * Add a unique alias to avoid any conflict in relation names due to
1606 : * pulled up subqueries in the query being built for a pushed down
1607 : * join.
1608 : */
1609 4086 : if (use_alias)
1610 1744 : appendStringInfo(buf, " %s%d", REL_ALIAS_PREFIX, foreignrel->relid);
1611 :
1612 4086 : table_close(rel, NoLock);
1613 : }
1614 : }
1615 :
1616 : /*
1617 : * Append FROM clause entry for the given relation into buf.
1618 : */
1619 : static void
1620 1988 : deparseRangeTblRef(StringInfo buf, PlannerInfo *root, RelOptInfo *foreignrel,
1621 : bool make_subquery, Index ignore_rel, List **ignore_conds,
1622 : List **params_list)
1623 : {
1624 1988 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
1625 :
1626 : /* Should only be called in these cases. */
1627 : Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
1628 :
1629 : Assert(fpinfo->local_conds == NIL);
1630 :
1631 : /* If make_subquery is true, deparse the relation as a subquery. */
1632 1988 : if (make_subquery)
1633 : {
1634 : List *retrieved_attrs;
1635 : int ncols;
1636 :
1637 : /*
1638 : * The given relation shouldn't contain the target relation, because
1639 : * this should only happen for input relations for a full join, and
1640 : * such relations can never contain an UPDATE/DELETE target.
1641 : */
1642 : Assert(ignore_rel == 0 ||
1643 : !bms_is_member(ignore_rel, foreignrel->relids));
1644 :
1645 : /* Deparse the subquery representing the relation. */
1646 56 : appendStringInfoChar(buf, '(');
1647 56 : deparseSelectStmtForRel(buf, root, foreignrel, NIL,
1648 : fpinfo->remote_conds, NIL,
1649 : false, false, true,
1650 : &retrieved_attrs, params_list);
1651 56 : appendStringInfoChar(buf, ')');
1652 :
1653 : /* Append the relation alias. */
1654 56 : appendStringInfo(buf, " %s%d", SUBQUERY_REL_ALIAS_PREFIX,
1655 : fpinfo->relation_index);
1656 :
1657 : /*
1658 : * Append the column aliases if needed. Note that the subquery emits
1659 : * expressions specified in the relation's reltarget (see
1660 : * deparseSubqueryTargetList).
1661 : */
1662 56 : ncols = list_length(foreignrel->reltarget->exprs);
1663 56 : if (ncols > 0)
1664 : {
1665 : int i;
1666 :
1667 48 : appendStringInfoChar(buf, '(');
1668 112 : for (i = 1; i <= ncols; i++)
1669 : {
1670 64 : if (i > 1)
1671 16 : appendStringInfoString(buf, ", ");
1672 :
1673 64 : appendStringInfo(buf, "%s%d", SUBQUERY_COL_ALIAS_PREFIX, i);
1674 : }
1675 48 : appendStringInfoChar(buf, ')');
1676 : }
1677 : }
1678 : else
1679 1932 : deparseFromExprForRel(buf, root, foreignrel, true, ignore_rel,
1680 : ignore_conds, params_list);
1681 1988 : }
1682 :
1683 : /*
1684 : * deparse remote INSERT statement
1685 : *
1686 : * The statement text is appended to buf, and we also create an integer List
1687 : * of the columns being retrieved by WITH CHECK OPTION or RETURNING (if any),
1688 : * which is returned to *retrieved_attrs.
1689 : */
1690 : void
1691 170 : deparseInsertSql(StringInfo buf, RangeTblEntry *rte,
1692 : Index rtindex, Relation rel,
1693 : List *targetAttrs, bool doNothing,
1694 : List *withCheckOptionList, List *returningList,
1695 : List **retrieved_attrs)
1696 : {
1697 : AttrNumber pindex;
1698 : bool first;
1699 : ListCell *lc;
1700 :
1701 170 : appendStringInfoString(buf, "INSERT INTO ");
1702 170 : deparseRelation(buf, rel);
1703 :
1704 170 : if (targetAttrs)
1705 : {
1706 170 : appendStringInfoChar(buf, '(');
1707 :
1708 170 : first = true;
1709 724 : foreach(lc, targetAttrs)
1710 : {
1711 554 : int attnum = lfirst_int(lc);
1712 :
1713 554 : if (!first)
1714 384 : appendStringInfoString(buf, ", ");
1715 554 : first = false;
1716 :
1717 554 : deparseColumnRef(buf, rtindex, attnum, rte, false);
1718 : }
1719 :
1720 170 : appendStringInfoString(buf, ") VALUES (");
1721 :
1722 170 : pindex = 1;
1723 170 : first = true;
1724 724 : foreach(lc, targetAttrs)
1725 : {
1726 554 : if (!first)
1727 384 : appendStringInfoString(buf, ", ");
1728 554 : first = false;
1729 :
1730 554 : appendStringInfo(buf, "$%d", pindex);
1731 554 : pindex++;
1732 : }
1733 :
1734 170 : appendStringInfoChar(buf, ')');
1735 : }
1736 : else
1737 0 : appendStringInfoString(buf, " DEFAULT VALUES");
1738 :
1739 170 : if (doNothing)
1740 6 : appendStringInfoString(buf, " ON CONFLICT DO NOTHING");
1741 :
1742 170 : deparseReturningList(buf, rte, rtindex, rel,
1743 170 : rel->trigdesc && rel->trigdesc->trig_insert_after_row,
1744 : withCheckOptionList, returningList, retrieved_attrs);
1745 170 : }
1746 :
1747 : /*
1748 : * deparse remote UPDATE statement
1749 : *
1750 : * The statement text is appended to buf, and we also create an integer List
1751 : * of the columns being retrieved by WITH CHECK OPTION or RETURNING (if any),
1752 : * which is returned to *retrieved_attrs.
1753 : */
1754 : void
1755 76 : deparseUpdateSql(StringInfo buf, RangeTblEntry *rte,
1756 : Index rtindex, Relation rel,
1757 : List *targetAttrs,
1758 : List *withCheckOptionList, List *returningList,
1759 : List **retrieved_attrs)
1760 : {
1761 : AttrNumber pindex;
1762 : bool first;
1763 : ListCell *lc;
1764 :
1765 76 : appendStringInfoString(buf, "UPDATE ");
1766 76 : deparseRelation(buf, rel);
1767 76 : appendStringInfoString(buf, " SET ");
1768 :
1769 76 : pindex = 2; /* ctid is always the first param */
1770 76 : first = true;
1771 188 : foreach(lc, targetAttrs)
1772 : {
1773 112 : int attnum = lfirst_int(lc);
1774 :
1775 112 : if (!first)
1776 36 : appendStringInfoString(buf, ", ");
1777 112 : first = false;
1778 :
1779 112 : deparseColumnRef(buf, rtindex, attnum, rte, false);
1780 112 : appendStringInfo(buf, " = $%d", pindex);
1781 112 : pindex++;
1782 : }
1783 76 : appendStringInfoString(buf, " WHERE ctid = $1");
1784 :
1785 76 : deparseReturningList(buf, rte, rtindex, rel,
1786 76 : rel->trigdesc && rel->trigdesc->trig_update_after_row,
1787 : withCheckOptionList, returningList, retrieved_attrs);
1788 76 : }
1789 :
1790 : /*
1791 : * deparse remote UPDATE statement
1792 : *
1793 : * 'buf' is the output buffer to append the statement to
1794 : * 'rtindex' is the RT index of the associated target relation
1795 : * 'rel' is the relation descriptor for the target relation
1796 : * 'foreignrel' is the RelOptInfo for the target relation or the join relation
1797 : * containing all base relations in the query
1798 : * 'targetlist' is the tlist of the underlying foreign-scan plan node
1799 : * 'targetAttrs' is the target columns of the UPDATE
1800 : * 'remote_conds' is the qual clauses that must be evaluated remotely
1801 : * '*params_list' is an output list of exprs that will become remote Params
1802 : * 'returningList' is the RETURNING targetlist
1803 : * '*retrieved_attrs' is an output list of integers of columns being retrieved
1804 : * by RETURNING (if any)
1805 : */
1806 : void
1807 82 : deparseDirectUpdateSql(StringInfo buf, PlannerInfo *root,
1808 : Index rtindex, Relation rel,
1809 : RelOptInfo *foreignrel,
1810 : List *targetlist,
1811 : List *targetAttrs,
1812 : List *remote_conds,
1813 : List **params_list,
1814 : List *returningList,
1815 : List **retrieved_attrs)
1816 : {
1817 : deparse_expr_cxt context;
1818 : int nestlevel;
1819 : bool first;
1820 : ListCell *lc;
1821 82 : RangeTblEntry *rte = planner_rt_fetch(rtindex, root);
1822 :
1823 : /* Set up context struct for recursion */
1824 82 : context.root = root;
1825 82 : context.foreignrel = foreignrel;
1826 82 : context.scanrel = foreignrel;
1827 82 : context.buf = buf;
1828 82 : context.params_list = params_list;
1829 :
1830 82 : appendStringInfoString(buf, "UPDATE ");
1831 82 : deparseRelation(buf, rel);
1832 82 : if (foreignrel->reloptkind == RELOPT_JOINREL)
1833 12 : appendStringInfo(buf, " %s%d", REL_ALIAS_PREFIX, rtindex);
1834 82 : appendStringInfoString(buf, " SET ");
1835 :
1836 : /* Make sure any constants in the exprs are printed portably */
1837 82 : nestlevel = set_transmission_modes();
1838 :
1839 82 : first = true;
1840 180 : foreach(lc, targetAttrs)
1841 : {
1842 98 : int attnum = lfirst_int(lc);
1843 98 : TargetEntry *tle = get_tle_by_resno(targetlist, attnum);
1844 :
1845 98 : if (!tle)
1846 0 : elog(ERROR, "attribute number %d not found in UPDATE targetlist",
1847 : attnum);
1848 :
1849 98 : if (!first)
1850 16 : appendStringInfoString(buf, ", ");
1851 98 : first = false;
1852 :
1853 98 : deparseColumnRef(buf, rtindex, attnum, rte, false);
1854 98 : appendStringInfoString(buf, " = ");
1855 98 : deparseExpr((Expr *) tle->expr, &context);
1856 : }
1857 :
1858 82 : reset_transmission_modes(nestlevel);
1859 :
1860 82 : if (foreignrel->reloptkind == RELOPT_JOINREL)
1861 : {
1862 12 : List *ignore_conds = NIL;
1863 :
1864 12 : appendStringInfoString(buf, " FROM ");
1865 12 : deparseFromExprForRel(buf, root, foreignrel, true, rtindex,
1866 : &ignore_conds, params_list);
1867 12 : remote_conds = list_concat(remote_conds, ignore_conds);
1868 : }
1869 :
1870 82 : if (remote_conds)
1871 : {
1872 54 : appendStringInfoString(buf, " WHERE ");
1873 54 : appendConditions(remote_conds, &context);
1874 : }
1875 :
1876 82 : if (foreignrel->reloptkind == RELOPT_JOINREL)
1877 12 : deparseExplicitTargetList(returningList, true, retrieved_attrs,
1878 : &context);
1879 : else
1880 70 : deparseReturningList(buf, rte, rtindex, rel, false,
1881 : NIL, returningList, retrieved_attrs);
1882 82 : }
1883 :
1884 : /*
1885 : * deparse remote DELETE statement
1886 : *
1887 : * The statement text is appended to buf, and we also create an integer List
1888 : * of the columns being retrieved by RETURNING (if any), which is returned
1889 : * to *retrieved_attrs.
1890 : */
1891 : void
1892 18 : deparseDeleteSql(StringInfo buf, RangeTblEntry *rte,
1893 : Index rtindex, Relation rel,
1894 : List *returningList,
1895 : List **retrieved_attrs)
1896 : {
1897 18 : appendStringInfoString(buf, "DELETE FROM ");
1898 18 : deparseRelation(buf, rel);
1899 18 : appendStringInfoString(buf, " WHERE ctid = $1");
1900 :
1901 18 : deparseReturningList(buf, rte, rtindex, rel,
1902 18 : rel->trigdesc && rel->trigdesc->trig_delete_after_row,
1903 : NIL, returningList, retrieved_attrs);
1904 18 : }
1905 :
1906 : /*
1907 : * deparse remote DELETE statement
1908 : *
1909 : * 'buf' is the output buffer to append the statement to
1910 : * 'rtindex' is the RT index of the associated target relation
1911 : * 'rel' is the relation descriptor for the target relation
1912 : * 'foreignrel' is the RelOptInfo for the target relation or the join relation
1913 : * containing all base relations in the query
1914 : * 'remote_conds' is the qual clauses that must be evaluated remotely
1915 : * '*params_list' is an output list of exprs that will become remote Params
1916 : * 'returningList' is the RETURNING targetlist
1917 : * '*retrieved_attrs' is an output list of integers of columns being retrieved
1918 : * by RETURNING (if any)
1919 : */
1920 : void
1921 84 : deparseDirectDeleteSql(StringInfo buf, PlannerInfo *root,
1922 : Index rtindex, Relation rel,
1923 : RelOptInfo *foreignrel,
1924 : List *remote_conds,
1925 : List **params_list,
1926 : List *returningList,
1927 : List **retrieved_attrs)
1928 : {
1929 : deparse_expr_cxt context;
1930 :
1931 : /* Set up context struct for recursion */
1932 84 : context.root = root;
1933 84 : context.foreignrel = foreignrel;
1934 84 : context.scanrel = foreignrel;
1935 84 : context.buf = buf;
1936 84 : context.params_list = params_list;
1937 :
1938 84 : appendStringInfoString(buf, "DELETE FROM ");
1939 84 : deparseRelation(buf, rel);
1940 84 : if (foreignrel->reloptkind == RELOPT_JOINREL)
1941 12 : appendStringInfo(buf, " %s%d", REL_ALIAS_PREFIX, rtindex);
1942 :
1943 84 : if (foreignrel->reloptkind == RELOPT_JOINREL)
1944 : {
1945 12 : List *ignore_conds = NIL;
1946 :
1947 12 : appendStringInfoString(buf, " USING ");
1948 12 : deparseFromExprForRel(buf, root, foreignrel, true, rtindex,
1949 : &ignore_conds, params_list);
1950 12 : remote_conds = list_concat(remote_conds, ignore_conds);
1951 : }
1952 :
1953 84 : if (remote_conds)
1954 : {
1955 28 : appendStringInfoString(buf, " WHERE ");
1956 28 : appendConditions(remote_conds, &context);
1957 : }
1958 :
1959 84 : if (foreignrel->reloptkind == RELOPT_JOINREL)
1960 12 : deparseExplicitTargetList(returningList, true, retrieved_attrs,
1961 : &context);
1962 : else
1963 72 : deparseReturningList(buf, planner_rt_fetch(rtindex, root),
1964 : rtindex, rel, false,
1965 : NIL, returningList, retrieved_attrs);
1966 84 : }
1967 :
1968 : /*
1969 : * Add a RETURNING clause, if needed, to an INSERT/UPDATE/DELETE.
1970 : */
1971 : static void
1972 406 : deparseReturningList(StringInfo buf, RangeTblEntry *rte,
1973 : Index rtindex, Relation rel,
1974 : bool trig_after_row,
1975 : List *withCheckOptionList,
1976 : List *returningList,
1977 : List **retrieved_attrs)
1978 : {
1979 406 : Bitmapset *attrs_used = NULL;
1980 :
1981 406 : if (trig_after_row)
1982 : {
1983 : /* whole-row reference acquires all non-system columns */
1984 40 : attrs_used =
1985 40 : bms_make_singleton(0 - FirstLowInvalidHeapAttributeNumber);
1986 : }
1987 :
1988 406 : if (withCheckOptionList != NIL)
1989 : {
1990 : /*
1991 : * We need the attrs, non-system and system, mentioned in the local
1992 : * query's WITH CHECK OPTION list.
1993 : *
1994 : * Note: we do this to ensure that WCO constraints will be evaluated
1995 : * on the data actually inserted/updated on the remote side, which
1996 : * might differ from the data supplied by the core code, for example
1997 : * as a result of remote triggers.
1998 : */
1999 28 : pull_varattnos((Node *) withCheckOptionList, rtindex,
2000 : &attrs_used);
2001 : }
2002 :
2003 406 : if (returningList != NIL)
2004 : {
2005 : /*
2006 : * We need the attrs, non-system and system, mentioned in the local
2007 : * query's RETURNING list.
2008 : */
2009 116 : pull_varattnos((Node *) returningList, rtindex,
2010 : &attrs_used);
2011 : }
2012 :
2013 406 : if (attrs_used != NULL)
2014 182 : deparseTargetList(buf, rte, rtindex, rel, true, attrs_used, false,
2015 : retrieved_attrs);
2016 : else
2017 224 : *retrieved_attrs = NIL;
2018 406 : }
2019 :
2020 : /*
2021 : * Construct SELECT statement to acquire size in blocks of given relation.
2022 : *
2023 : * Note: we use local definition of block size, not remote definition.
2024 : * This is perhaps debatable.
2025 : *
2026 : * Note: pg_relation_size() exists in 8.1 and later.
2027 : */
2028 : void
2029 48 : deparseAnalyzeSizeSql(StringInfo buf, Relation rel)
2030 : {
2031 : StringInfoData relname;
2032 :
2033 : /* We'll need the remote relation name as a literal. */
2034 48 : initStringInfo(&relname);
2035 48 : deparseRelation(&relname, rel);
2036 :
2037 48 : appendStringInfoString(buf, "SELECT pg_catalog.pg_relation_size(");
2038 48 : deparseStringLiteral(buf, relname.data);
2039 48 : appendStringInfo(buf, "::pg_catalog.regclass) / %d", BLCKSZ);
2040 48 : }
2041 :
2042 : /*
2043 : * Construct SELECT statement to acquire sample rows of given relation.
2044 : *
2045 : * SELECT command is appended to buf, and list of columns retrieved
2046 : * is returned to *retrieved_attrs.
2047 : */
2048 : void
2049 48 : deparseAnalyzeSql(StringInfo buf, Relation rel, List **retrieved_attrs)
2050 : {
2051 48 : Oid relid = RelationGetRelid(rel);
2052 48 : TupleDesc tupdesc = RelationGetDescr(rel);
2053 : int i;
2054 : char *colname;
2055 : List *options;
2056 : ListCell *lc;
2057 48 : bool first = true;
2058 :
2059 48 : *retrieved_attrs = NIL;
2060 :
2061 48 : appendStringInfoString(buf, "SELECT ");
2062 212 : for (i = 0; i < tupdesc->natts; i++)
2063 : {
2064 : /* Ignore dropped columns. */
2065 164 : if (TupleDescAttr(tupdesc, i)->attisdropped)
2066 4 : continue;
2067 :
2068 160 : if (!first)
2069 112 : appendStringInfoString(buf, ", ");
2070 160 : first = false;
2071 :
2072 : /* Use attribute name or column_name option. */
2073 160 : colname = NameStr(TupleDescAttr(tupdesc, i)->attname);
2074 160 : options = GetForeignColumnOptions(relid, i + 1);
2075 :
2076 160 : foreach(lc, options)
2077 : {
2078 4 : DefElem *def = (DefElem *) lfirst(lc);
2079 :
2080 4 : if (strcmp(def->defname, "column_name") == 0)
2081 : {
2082 4 : colname = defGetString(def);
2083 4 : break;
2084 : }
2085 : }
2086 :
2087 160 : appendStringInfoString(buf, quote_identifier(colname));
2088 :
2089 160 : *retrieved_attrs = lappend_int(*retrieved_attrs, i + 1);
2090 : }
2091 :
2092 : /* Don't generate bad syntax for zero-column relation. */
2093 48 : if (first)
2094 0 : appendStringInfoString(buf, "NULL");
2095 :
2096 : /*
2097 : * Construct FROM clause
2098 : */
2099 48 : appendStringInfoString(buf, " FROM ");
2100 48 : deparseRelation(buf, rel);
2101 48 : }
2102 :
2103 : /*
2104 : * Construct name to use for given column, and emit it into buf.
2105 : * If it has a column_name FDW option, use that instead of attribute name.
2106 : *
2107 : * If qualify_col is true, qualify column name with the alias of relation.
2108 : */
2109 : static void
2110 18664 : deparseColumnRef(StringInfo buf, int varno, int varattno, RangeTblEntry *rte,
2111 : bool qualify_col)
2112 : {
2113 : /* We support fetching the remote side's CTID and OID. */
2114 18664 : if (varattno == SelfItemPointerAttributeNumber)
2115 : {
2116 96 : if (qualify_col)
2117 92 : ADD_REL_QUALIFIER(buf, varno);
2118 96 : appendStringInfoString(buf, "ctid");
2119 : }
2120 18568 : else if (varattno < 0)
2121 : {
2122 : /*
2123 : * All other system attributes are fetched as 0, except for table OID,
2124 : * which is fetched as the local table OID. However, we must be
2125 : * careful; the table could be beneath an outer join, in which case it
2126 : * must go to NULL whenever the rest of the row does.
2127 : */
2128 0 : Oid fetchval = 0;
2129 :
2130 0 : if (varattno == TableOidAttributeNumber)
2131 0 : fetchval = rte->relid;
2132 :
2133 0 : if (qualify_col)
2134 : {
2135 0 : appendStringInfoString(buf, "CASE WHEN (");
2136 0 : ADD_REL_QUALIFIER(buf, varno);
2137 0 : appendStringInfo(buf, "*)::text IS NOT NULL THEN %u END", fetchval);
2138 : }
2139 : else
2140 0 : appendStringInfo(buf, "%u", fetchval);
2141 : }
2142 18568 : else if (varattno == 0)
2143 : {
2144 : /* Whole row reference */
2145 : Relation rel;
2146 : Bitmapset *attrs_used;
2147 :
2148 : /* Required only to be passed down to deparseTargetList(). */
2149 : List *retrieved_attrs;
2150 :
2151 : /*
2152 : * The lock on the relation will be held by upper callers, so it's
2153 : * fine to open it with no lock here.
2154 : */
2155 392 : rel = table_open(rte->relid, NoLock);
2156 :
2157 : /*
2158 : * The local name of the foreign table can not be recognized by the
2159 : * foreign server and the table it references on foreign server might
2160 : * have different column ordering or different columns than those
2161 : * declared locally. Hence we have to deparse whole-row reference as
2162 : * ROW(columns referenced locally). Construct this by deparsing a
2163 : * "whole row" attribute.
2164 : */
2165 392 : attrs_used = bms_add_member(NULL,
2166 : 0 - FirstLowInvalidHeapAttributeNumber);
2167 :
2168 : /*
2169 : * In case the whole-row reference is under an outer join then it has
2170 : * to go NULL whenever the rest of the row goes NULL. Deparsing a join
2171 : * query would always involve multiple relations, thus qualify_col
2172 : * would be true.
2173 : */
2174 392 : if (qualify_col)
2175 : {
2176 384 : appendStringInfoString(buf, "CASE WHEN (");
2177 384 : ADD_REL_QUALIFIER(buf, varno);
2178 384 : appendStringInfoString(buf, "*)::text IS NOT NULL THEN ");
2179 : }
2180 :
2181 392 : appendStringInfoString(buf, "ROW(");
2182 392 : deparseTargetList(buf, rte, varno, rel, false, attrs_used, qualify_col,
2183 : &retrieved_attrs);
2184 392 : appendStringInfoChar(buf, ')');
2185 :
2186 : /* Complete the CASE WHEN statement started above. */
2187 392 : if (qualify_col)
2188 384 : appendStringInfoString(buf, " END");
2189 :
2190 392 : table_close(rel, NoLock);
2191 392 : bms_free(attrs_used);
2192 : }
2193 : else
2194 : {
2195 18176 : char *colname = NULL;
2196 : List *options;
2197 : ListCell *lc;
2198 :
2199 : /* varno must not be any of OUTER_VAR, INNER_VAR and INDEX_VAR. */
2200 : Assert(!IS_SPECIAL_VARNO(varno));
2201 :
2202 : /*
2203 : * If it's a column of a foreign table, and it has the column_name FDW
2204 : * option, use that value.
2205 : */
2206 18176 : options = GetForeignColumnOptions(rte->relid, varattno);
2207 18176 : foreach(lc, options)
2208 : {
2209 4700 : DefElem *def = (DefElem *) lfirst(lc);
2210 :
2211 4700 : if (strcmp(def->defname, "column_name") == 0)
2212 : {
2213 4700 : colname = defGetString(def);
2214 4700 : break;
2215 : }
2216 : }
2217 :
2218 : /*
2219 : * If it's a column of a regular table or it doesn't have column_name
2220 : * FDW option, use attribute name.
2221 : */
2222 18176 : if (colname == NULL)
2223 13476 : colname = get_attname(rte->relid, varattno, false);
2224 :
2225 18176 : if (qualify_col)
2226 8272 : ADD_REL_QUALIFIER(buf, varno);
2227 :
2228 18176 : appendStringInfoString(buf, quote_identifier(colname));
2229 : }
2230 18664 : }
2231 :
2232 : /*
2233 : * Append remote name of specified foreign table to buf.
2234 : * Use value of table_name FDW option (if any) instead of relation's name.
2235 : * Similarly, schema_name FDW option overrides schema name.
2236 : */
2237 : static void
2238 4612 : deparseRelation(StringInfo buf, Relation rel)
2239 : {
2240 : ForeignTable *table;
2241 4612 : const char *nspname = NULL;
2242 4612 : const char *relname = NULL;
2243 : ListCell *lc;
2244 :
2245 : /* obtain additional catalog information. */
2246 4612 : table = GetForeignTable(RelationGetRelid(rel));
2247 :
2248 : /*
2249 : * Use value of FDW options if any, instead of the name of object itself.
2250 : */
2251 14910 : foreach(lc, table->options)
2252 : {
2253 10298 : DefElem *def = (DefElem *) lfirst(lc);
2254 :
2255 10298 : if (strcmp(def->defname, "schema_name") == 0)
2256 3174 : nspname = defGetString(def);
2257 7124 : else if (strcmp(def->defname, "table_name") == 0)
2258 4612 : relname = defGetString(def);
2259 : }
2260 :
2261 : /*
2262 : * Note: we could skip printing the schema name if it's pg_catalog, but
2263 : * that doesn't seem worth the trouble.
2264 : */
2265 4612 : if (nspname == NULL)
2266 1438 : nspname = get_namespace_name(RelationGetNamespace(rel));
2267 4612 : if (relname == NULL)
2268 0 : relname = RelationGetRelationName(rel);
2269 :
2270 4612 : appendStringInfo(buf, "%s.%s",
2271 : quote_identifier(nspname), quote_identifier(relname));
2272 4612 : }
2273 :
2274 : /*
2275 : * Append a SQL string literal representing "val" to buf.
2276 : */
2277 : void
2278 448 : deparseStringLiteral(StringInfo buf, const char *val)
2279 : {
2280 : const char *valptr;
2281 :
2282 : /*
2283 : * Rather than making assumptions about the remote server's value of
2284 : * standard_conforming_strings, always use E'foo' syntax if there are any
2285 : * backslashes. This will fail on remote servers before 8.1, but those
2286 : * are long out of support.
2287 : */
2288 448 : if (strchr(val, '\\') != NULL)
2289 2 : appendStringInfoChar(buf, ESCAPE_STRING_SYNTAX);
2290 448 : appendStringInfoChar(buf, '\'');
2291 3398 : for (valptr = val; *valptr; valptr++)
2292 : {
2293 2950 : char ch = *valptr;
2294 :
2295 2950 : if (SQL_STR_DOUBLE(ch, true))
2296 4 : appendStringInfoChar(buf, ch);
2297 2950 : appendStringInfoChar(buf, ch);
2298 : }
2299 448 : appendStringInfoChar(buf, '\'');
2300 448 : }
2301 :
2302 : /*
2303 : * Deparse given expression into context->buf.
2304 : *
2305 : * This function must support all the same node types that foreign_expr_walker
2306 : * accepts.
2307 : *
2308 : * Note: unlike ruleutils.c, we just use a simple hard-wired parenthesization
2309 : * scheme: anything more complex than a Var, Const, function call or cast
2310 : * should be self-parenthesized.
2311 : */
2312 : static void
2313 16654 : deparseExpr(Expr *node, deparse_expr_cxt *context)
2314 : {
2315 16654 : if (node == NULL)
2316 0 : return;
2317 :
2318 16654 : switch (nodeTag(node))
2319 : {
2320 : case T_Var:
2321 9706 : deparseVar((Var *) node, context);
2322 9706 : break;
2323 : case T_Const:
2324 2600 : deparseConst((Const *) node, context, 0);
2325 2600 : break;
2326 : case T_Param:
2327 40 : deparseParam((Param *) node, context);
2328 40 : break;
2329 : case T_SubscriptingRef:
2330 2 : deparseSubscriptingRef((SubscriptingRef *) node, context);
2331 2 : break;
2332 : case T_FuncExpr:
2333 96 : deparseFuncExpr((FuncExpr *) node, context);
2334 96 : break;
2335 : case T_OpExpr:
2336 3524 : deparseOpExpr((OpExpr *) node, context);
2337 3524 : break;
2338 : case T_DistinctExpr:
2339 2 : deparseDistinctExpr((DistinctExpr *) node, context);
2340 2 : break;
2341 : case T_ScalarArrayOpExpr:
2342 8 : deparseScalarArrayOpExpr((ScalarArrayOpExpr *) node, context);
2343 8 : break;
2344 : case T_RelabelType:
2345 64 : deparseRelabelType((RelabelType *) node, context);
2346 64 : break;
2347 : case T_BoolExpr:
2348 76 : deparseBoolExpr((BoolExpr *) node, context);
2349 76 : break;
2350 : case T_NullTest:
2351 56 : deparseNullTest((NullTest *) node, context);
2352 56 : break;
2353 : case T_ArrayExpr:
2354 8 : deparseArrayExpr((ArrayExpr *) node, context);
2355 8 : break;
2356 : case T_Aggref:
2357 472 : deparseAggref((Aggref *) node, context);
2358 472 : break;
2359 : default:
2360 0 : elog(ERROR, "unsupported expression type for deparse: %d",
2361 : (int) nodeTag(node));
2362 : break;
2363 : }
2364 : }
2365 :
2366 : /*
2367 : * Deparse given Var node into context->buf.
2368 : *
2369 : * If the Var belongs to the foreign relation, just print its remote name.
2370 : * Otherwise, it's effectively a Param (and will in fact be a Param at
2371 : * run time). Handle it the same way we handle plain Params --- see
2372 : * deparseParam for comments.
2373 : */
2374 : static void
2375 9706 : deparseVar(Var *node, deparse_expr_cxt *context)
2376 : {
2377 9706 : Relids relids = context->scanrel->relids;
2378 : int relno;
2379 : int colno;
2380 :
2381 : /* Qualify columns when multiple relations are involved. */
2382 9706 : bool qualify_col = (bms_membership(relids) == BMS_MULTIPLE);
2383 :
2384 : /*
2385 : * If the Var belongs to the foreign relation that is deparsed as a
2386 : * subquery, use the relation and column alias to the Var provided by the
2387 : * subquery, instead of the remote name.
2388 : */
2389 9706 : if (is_subquery_var(node, context->scanrel, &relno, &colno))
2390 : {
2391 168 : appendStringInfo(context->buf, "%s%d.%s%d",
2392 : SUBQUERY_REL_ALIAS_PREFIX, relno,
2393 : SUBQUERY_COL_ALIAS_PREFIX, colno);
2394 168 : return;
2395 : }
2396 :
2397 9538 : if (bms_is_member(node->varno, relids) && node->varlevelsup == 0)
2398 27774 : deparseColumnRef(context->buf, node->varno, node->varattno,
2399 18516 : planner_rt_fetch(node->varno, context->root),
2400 : qualify_col);
2401 : else
2402 : {
2403 : /* Treat like a Param */
2404 280 : if (context->params_list)
2405 : {
2406 8 : int pindex = 0;
2407 : ListCell *lc;
2408 :
2409 : /* find its index in params_list */
2410 8 : foreach(lc, *context->params_list)
2411 : {
2412 0 : pindex++;
2413 0 : if (equal(node, (Node *) lfirst(lc)))
2414 0 : break;
2415 : }
2416 8 : if (lc == NULL)
2417 : {
2418 : /* not in list, so add it */
2419 8 : pindex++;
2420 8 : *context->params_list = lappend(*context->params_list, node);
2421 : }
2422 :
2423 8 : printRemoteParam(pindex, node->vartype, node->vartypmod, context);
2424 : }
2425 : else
2426 : {
2427 272 : printRemotePlaceholder(node->vartype, node->vartypmod, context);
2428 : }
2429 : }
2430 : }
2431 :
2432 : /*
2433 : * Deparse given constant value into context->buf.
2434 : *
2435 : * This function has to be kept in sync with ruleutils.c's get_const_expr.
2436 : * As for that function, showtype can be -1 to never show "::typename" decoration,
2437 : * or +1 to always show it, or 0 to show it only if the constant wouldn't be assumed
2438 : * to be the right type by default.
2439 : */
2440 : static void
2441 2600 : deparseConst(Const *node, deparse_expr_cxt *context, int showtype)
2442 : {
2443 2600 : StringInfo buf = context->buf;
2444 : Oid typoutput;
2445 : bool typIsVarlena;
2446 : char *extval;
2447 2600 : bool isfloat = false;
2448 : bool needlabel;
2449 :
2450 2600 : if (node->constisnull)
2451 : {
2452 14 : appendStringInfoString(buf, "NULL");
2453 14 : if (showtype >= 0)
2454 14 : appendStringInfo(buf, "::%s",
2455 : deparse_type_name(node->consttype,
2456 : node->consttypmod));
2457 28 : return;
2458 : }
2459 :
2460 2586 : getTypeOutputInfo(node->consttype,
2461 : &typoutput, &typIsVarlena);
2462 2586 : extval = OidOutputFunctionCall(typoutput, node->constvalue);
2463 :
2464 2586 : switch (node->consttype)
2465 : {
2466 : case INT2OID:
2467 : case INT4OID:
2468 : case INT8OID:
2469 : case OIDOID:
2470 : case FLOAT4OID:
2471 : case FLOAT8OID:
2472 : case NUMERICOID:
2473 : {
2474 : /*
2475 : * No need to quote unless it's a special value such as 'NaN'.
2476 : * See comments in get_const_expr().
2477 : */
2478 2458 : if (strspn(extval, "0123456789+-eE.") == strlen(extval))
2479 : {
2480 2458 : if (extval[0] == '+' || extval[0] == '-')
2481 2 : appendStringInfo(buf, "(%s)", extval);
2482 : else
2483 2456 : appendStringInfoString(buf, extval);
2484 2458 : if (strcspn(extval, "eE.") != strlen(extval))
2485 4 : isfloat = true; /* it looks like a float */
2486 : }
2487 : else
2488 0 : appendStringInfo(buf, "'%s'", extval);
2489 : }
2490 2458 : break;
2491 : case BITOID:
2492 : case VARBITOID:
2493 0 : appendStringInfo(buf, "B'%s'", extval);
2494 0 : break;
2495 : case BOOLOID:
2496 0 : if (strcmp(extval, "t") == 0)
2497 0 : appendStringInfoString(buf, "true");
2498 : else
2499 0 : appendStringInfoString(buf, "false");
2500 0 : break;
2501 : default:
2502 128 : deparseStringLiteral(buf, extval);
2503 128 : break;
2504 : }
2505 :
2506 2586 : pfree(extval);
2507 :
2508 2586 : if (showtype < 0)
2509 0 : return;
2510 :
2511 : /*
2512 : * For showtype == 0, append ::typename unless the constant will be
2513 : * implicitly typed as the right type when it is read in.
2514 : *
2515 : * XXX this code has to be kept in sync with the behavior of the parser,
2516 : * especially make_const.
2517 : */
2518 2586 : switch (node->consttype)
2519 : {
2520 : case BOOLOID:
2521 : case INT4OID:
2522 : case UNKNOWNOID:
2523 2090 : needlabel = false;
2524 2090 : break;
2525 : case NUMERICOID:
2526 44 : needlabel = !isfloat || (node->consttypmod >= 0);
2527 44 : break;
2528 : default:
2529 452 : needlabel = true;
2530 452 : break;
2531 : }
2532 2586 : if (needlabel || showtype > 0)
2533 492 : appendStringInfo(buf, "::%s",
2534 : deparse_type_name(node->consttype,
2535 : node->consttypmod));
2536 : }
2537 :
2538 : /*
2539 : * Deparse given Param node.
2540 : *
2541 : * If we're generating the query "for real", add the Param to
2542 : * context->params_list if it's not already present, and then use its index
2543 : * in that list as the remote parameter number. During EXPLAIN, there's
2544 : * no need to identify a parameter number.
2545 : */
2546 : static void
2547 40 : deparseParam(Param *node, deparse_expr_cxt *context)
2548 : {
2549 40 : if (context->params_list)
2550 : {
2551 26 : int pindex = 0;
2552 : ListCell *lc;
2553 :
2554 : /* find its index in params_list */
2555 30 : foreach(lc, *context->params_list)
2556 : {
2557 4 : pindex++;
2558 4 : if (equal(node, (Node *) lfirst(lc)))
2559 0 : break;
2560 : }
2561 26 : if (lc == NULL)
2562 : {
2563 : /* not in list, so add it */
2564 26 : pindex++;
2565 26 : *context->params_list = lappend(*context->params_list, node);
2566 : }
2567 :
2568 26 : printRemoteParam(pindex, node->paramtype, node->paramtypmod, context);
2569 : }
2570 : else
2571 : {
2572 14 : printRemotePlaceholder(node->paramtype, node->paramtypmod, context);
2573 : }
2574 40 : }
2575 :
2576 : /*
2577 : * Deparse a container subscript expression.
2578 : */
2579 : static void
2580 2 : deparseSubscriptingRef(SubscriptingRef *node, deparse_expr_cxt *context)
2581 : {
2582 2 : StringInfo buf = context->buf;
2583 : ListCell *lowlist_item;
2584 : ListCell *uplist_item;
2585 :
2586 : /* Always parenthesize the expression. */
2587 2 : appendStringInfoChar(buf, '(');
2588 :
2589 : /*
2590 : * Deparse referenced array expression first. If that expression includes
2591 : * a cast, we have to parenthesize to prevent the array subscript from
2592 : * being taken as typename decoration. We can avoid that in the typical
2593 : * case of subscripting a Var, but otherwise do it.
2594 : */
2595 2 : if (IsA(node->refexpr, Var))
2596 0 : deparseExpr(node->refexpr, context);
2597 : else
2598 : {
2599 2 : appendStringInfoChar(buf, '(');
2600 2 : deparseExpr(node->refexpr, context);
2601 2 : appendStringInfoChar(buf, ')');
2602 : }
2603 :
2604 : /* Deparse subscript expressions. */
2605 2 : lowlist_item = list_head(node->reflowerindexpr); /* could be NULL */
2606 4 : foreach(uplist_item, node->refupperindexpr)
2607 : {
2608 2 : appendStringInfoChar(buf, '[');
2609 2 : if (lowlist_item)
2610 : {
2611 0 : deparseExpr(lfirst(lowlist_item), context);
2612 0 : appendStringInfoChar(buf, ':');
2613 0 : lowlist_item = lnext(node->reflowerindexpr, lowlist_item);
2614 : }
2615 2 : deparseExpr(lfirst(uplist_item), context);
2616 2 : appendStringInfoChar(buf, ']');
2617 : }
2618 :
2619 2 : appendStringInfoChar(buf, ')');
2620 2 : }
2621 :
2622 : /*
2623 : * Deparse a function call.
2624 : */
2625 : static void
2626 96 : deparseFuncExpr(FuncExpr *node, deparse_expr_cxt *context)
2627 : {
2628 96 : StringInfo buf = context->buf;
2629 : bool use_variadic;
2630 : bool first;
2631 : ListCell *arg;
2632 :
2633 : /*
2634 : * If the function call came from an implicit coercion, then just show the
2635 : * first argument.
2636 : */
2637 96 : if (node->funcformat == COERCE_IMPLICIT_CAST)
2638 : {
2639 44 : deparseExpr((Expr *) linitial(node->args), context);
2640 44 : return;
2641 : }
2642 :
2643 : /*
2644 : * If the function call came from a cast, then show the first argument
2645 : * plus an explicit cast operation.
2646 : */
2647 52 : if (node->funcformat == COERCE_EXPLICIT_CAST)
2648 : {
2649 0 : Oid rettype = node->funcresulttype;
2650 : int32 coercedTypmod;
2651 :
2652 : /* Get the typmod if this is a length-coercion function */
2653 0 : (void) exprIsLengthCoercion((Node *) node, &coercedTypmod);
2654 :
2655 0 : deparseExpr((Expr *) linitial(node->args), context);
2656 0 : appendStringInfo(buf, "::%s",
2657 : deparse_type_name(rettype, coercedTypmod));
2658 0 : return;
2659 : }
2660 :
2661 : /* Check if need to print VARIADIC (cf. ruleutils.c) */
2662 52 : use_variadic = node->funcvariadic;
2663 :
2664 : /*
2665 : * Normal function: display as proname(args).
2666 : */
2667 52 : appendFunctionName(node->funcid, context);
2668 52 : appendStringInfoChar(buf, '(');
2669 :
2670 : /* ... and all the arguments */
2671 52 : first = true;
2672 106 : foreach(arg, node->args)
2673 : {
2674 54 : if (!first)
2675 2 : appendStringInfoString(buf, ", ");
2676 54 : if (use_variadic && lnext(node->args, arg) == NULL)
2677 0 : appendStringInfoString(buf, "VARIADIC ");
2678 54 : deparseExpr((Expr *) lfirst(arg), context);
2679 54 : first = false;
2680 : }
2681 52 : appendStringInfoChar(buf, ')');
2682 : }
2683 :
2684 : /*
2685 : * Deparse given operator expression. To avoid problems around
2686 : * priority of operations, we always parenthesize the arguments.
2687 : */
2688 : static void
2689 3524 : deparseOpExpr(OpExpr *node, deparse_expr_cxt *context)
2690 : {
2691 3524 : StringInfo buf = context->buf;
2692 : HeapTuple tuple;
2693 : Form_pg_operator form;
2694 : char oprkind;
2695 : ListCell *arg;
2696 :
2697 : /* Retrieve information about the operator from system catalog. */
2698 3524 : tuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(node->opno));
2699 3524 : if (!HeapTupleIsValid(tuple))
2700 0 : elog(ERROR, "cache lookup failed for operator %u", node->opno);
2701 3524 : form = (Form_pg_operator) GETSTRUCT(tuple);
2702 3524 : oprkind = form->oprkind;
2703 :
2704 : /* Sanity check. */
2705 : Assert((oprkind == 'r' && list_length(node->args) == 1) ||
2706 : (oprkind == 'l' && list_length(node->args) == 1) ||
2707 : (oprkind == 'b' && list_length(node->args) == 2));
2708 :
2709 : /* Always parenthesize the expression. */
2710 3524 : appendStringInfoChar(buf, '(');
2711 :
2712 : /* Deparse left operand. */
2713 3524 : if (oprkind == 'r' || oprkind == 'b')
2714 : {
2715 3518 : arg = list_head(node->args);
2716 3518 : deparseExpr(lfirst(arg), context);
2717 3518 : appendStringInfoChar(buf, ' ');
2718 : }
2719 :
2720 : /* Deparse operator name. */
2721 3524 : deparseOperatorName(buf, form);
2722 :
2723 : /* Deparse right operand. */
2724 3524 : if (oprkind == 'l' || oprkind == 'b')
2725 : {
2726 3522 : arg = list_tail(node->args);
2727 3522 : appendStringInfoChar(buf, ' ');
2728 3522 : deparseExpr(lfirst(arg), context);
2729 : }
2730 :
2731 3524 : appendStringInfoChar(buf, ')');
2732 :
2733 3524 : ReleaseSysCache(tuple);
2734 3524 : }
2735 :
2736 : /*
2737 : * Print the name of an operator.
2738 : */
2739 : static void
2740 3540 : deparseOperatorName(StringInfo buf, Form_pg_operator opform)
2741 : {
2742 : char *opname;
2743 :
2744 : /* opname is not a SQL identifier, so we should not quote it. */
2745 3540 : opname = NameStr(opform->oprname);
2746 :
2747 : /* Print schema name only if it's not pg_catalog */
2748 3540 : if (opform->oprnamespace != PG_CATALOG_NAMESPACE)
2749 : {
2750 : const char *opnspname;
2751 :
2752 18 : opnspname = get_namespace_name(opform->oprnamespace);
2753 : /* Print fully qualified operator name. */
2754 18 : appendStringInfo(buf, "OPERATOR(%s.%s)",
2755 : quote_identifier(opnspname), opname);
2756 : }
2757 : else
2758 : {
2759 : /* Just print operator name. */
2760 3522 : appendStringInfoString(buf, opname);
2761 : }
2762 3540 : }
2763 :
2764 : /*
2765 : * Deparse IS DISTINCT FROM.
2766 : */
2767 : static void
2768 2 : deparseDistinctExpr(DistinctExpr *node, deparse_expr_cxt *context)
2769 : {
2770 2 : StringInfo buf = context->buf;
2771 :
2772 : Assert(list_length(node->args) == 2);
2773 :
2774 2 : appendStringInfoChar(buf, '(');
2775 2 : deparseExpr(linitial(node->args), context);
2776 2 : appendStringInfoString(buf, " IS DISTINCT FROM ");
2777 2 : deparseExpr(lsecond(node->args), context);
2778 2 : appendStringInfoChar(buf, ')');
2779 2 : }
2780 :
2781 : /*
2782 : * Deparse given ScalarArrayOpExpr expression. To avoid problems
2783 : * around priority of operations, we always parenthesize the arguments.
2784 : */
2785 : static void
2786 8 : deparseScalarArrayOpExpr(ScalarArrayOpExpr *node, deparse_expr_cxt *context)
2787 : {
2788 8 : StringInfo buf = context->buf;
2789 : HeapTuple tuple;
2790 : Form_pg_operator form;
2791 : Expr *arg1;
2792 : Expr *arg2;
2793 :
2794 : /* Retrieve information about the operator from system catalog. */
2795 8 : tuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(node->opno));
2796 8 : if (!HeapTupleIsValid(tuple))
2797 0 : elog(ERROR, "cache lookup failed for operator %u", node->opno);
2798 8 : form = (Form_pg_operator) GETSTRUCT(tuple);
2799 :
2800 : /* Sanity check. */
2801 : Assert(list_length(node->args) == 2);
2802 :
2803 : /* Always parenthesize the expression. */
2804 8 : appendStringInfoChar(buf, '(');
2805 :
2806 : /* Deparse left operand. */
2807 8 : arg1 = linitial(node->args);
2808 8 : deparseExpr(arg1, context);
2809 8 : appendStringInfoChar(buf, ' ');
2810 :
2811 : /* Deparse operator name plus decoration. */
2812 8 : deparseOperatorName(buf, form);
2813 8 : appendStringInfo(buf, " %s (", node->useOr ? "ANY" : "ALL");
2814 :
2815 : /* Deparse right operand. */
2816 8 : arg2 = lsecond(node->args);
2817 8 : deparseExpr(arg2, context);
2818 :
2819 8 : appendStringInfoChar(buf, ')');
2820 :
2821 : /* Always parenthesize the expression. */
2822 8 : appendStringInfoChar(buf, ')');
2823 :
2824 8 : ReleaseSysCache(tuple);
2825 8 : }
2826 :
2827 : /*
2828 : * Deparse a RelabelType (binary-compatible cast) node.
2829 : */
2830 : static void
2831 64 : deparseRelabelType(RelabelType *node, deparse_expr_cxt *context)
2832 : {
2833 64 : deparseExpr(node->arg, context);
2834 64 : if (node->relabelformat != COERCE_IMPLICIT_CAST)
2835 0 : appendStringInfo(context->buf, "::%s",
2836 : deparse_type_name(node->resulttype,
2837 : node->resulttypmod));
2838 64 : }
2839 :
2840 : /*
2841 : * Deparse a BoolExpr node.
2842 : */
2843 : static void
2844 76 : deparseBoolExpr(BoolExpr *node, deparse_expr_cxt *context)
2845 : {
2846 76 : StringInfo buf = context->buf;
2847 76 : const char *op = NULL; /* keep compiler quiet */
2848 : bool first;
2849 : ListCell *lc;
2850 :
2851 76 : switch (node->boolop)
2852 : {
2853 : case AND_EXPR:
2854 36 : op = "AND";
2855 36 : break;
2856 : case OR_EXPR:
2857 40 : op = "OR";
2858 40 : break;
2859 : case NOT_EXPR:
2860 0 : appendStringInfoString(buf, "(NOT ");
2861 0 : deparseExpr(linitial(node->args), context);
2862 0 : appendStringInfoChar(buf, ')');
2863 0 : return;
2864 : }
2865 :
2866 76 : appendStringInfoChar(buf, '(');
2867 76 : first = true;
2868 228 : foreach(lc, node->args)
2869 : {
2870 152 : if (!first)
2871 76 : appendStringInfo(buf, " %s ", op);
2872 152 : deparseExpr((Expr *) lfirst(lc), context);
2873 152 : first = false;
2874 : }
2875 76 : appendStringInfoChar(buf, ')');
2876 : }
2877 :
2878 : /*
2879 : * Deparse IS [NOT] NULL expression.
2880 : */
2881 : static void
2882 56 : deparseNullTest(NullTest *node, deparse_expr_cxt *context)
2883 : {
2884 56 : StringInfo buf = context->buf;
2885 :
2886 56 : appendStringInfoChar(buf, '(');
2887 56 : deparseExpr(node->arg, context);
2888 :
2889 : /*
2890 : * For scalar inputs, we prefer to print as IS [NOT] NULL, which is
2891 : * shorter and traditional. If it's a rowtype input but we're applying a
2892 : * scalar test, must print IS [NOT] DISTINCT FROM NULL to be semantically
2893 : * correct.
2894 : */
2895 56 : if (node->argisrow || !type_is_rowtype(exprType((Node *) node->arg)))
2896 : {
2897 112 : if (node->nulltesttype == IS_NULL)
2898 38 : appendStringInfoString(buf, " IS NULL)");
2899 : else
2900 18 : appendStringInfoString(buf, " IS NOT NULL)");
2901 : }
2902 : else
2903 : {
2904 0 : if (node->nulltesttype == IS_NULL)
2905 0 : appendStringInfoString(buf, " IS NOT DISTINCT FROM NULL)");
2906 : else
2907 0 : appendStringInfoString(buf, " IS DISTINCT FROM NULL)");
2908 : }
2909 56 : }
2910 :
2911 : /*
2912 : * Deparse ARRAY[...] construct.
2913 : */
2914 : static void
2915 8 : deparseArrayExpr(ArrayExpr *node, deparse_expr_cxt *context)
2916 : {
2917 8 : StringInfo buf = context->buf;
2918 8 : bool first = true;
2919 : ListCell *lc;
2920 :
2921 8 : appendStringInfoString(buf, "ARRAY[");
2922 24 : foreach(lc, node->elements)
2923 : {
2924 16 : if (!first)
2925 8 : appendStringInfoString(buf, ", ");
2926 16 : deparseExpr(lfirst(lc), context);
2927 16 : first = false;
2928 : }
2929 8 : appendStringInfoChar(buf, ']');
2930 :
2931 : /* If the array is empty, we need an explicit cast to the array type. */
2932 8 : if (node->elements == NIL)
2933 0 : appendStringInfo(buf, "::%s",
2934 : deparse_type_name(node->array_typeid, -1));
2935 8 : }
2936 :
2937 : /*
2938 : * Deparse an Aggref node.
2939 : */
2940 : static void
2941 472 : deparseAggref(Aggref *node, deparse_expr_cxt *context)
2942 : {
2943 472 : StringInfo buf = context->buf;
2944 : bool use_variadic;
2945 :
2946 : /* Only basic, non-split aggregation accepted. */
2947 : Assert(node->aggsplit == AGGSPLIT_SIMPLE);
2948 :
2949 : /* Check if need to print VARIADIC (cf. ruleutils.c) */
2950 472 : use_variadic = node->aggvariadic;
2951 :
2952 : /* Find aggregate name from aggfnoid which is a pg_proc entry */
2953 472 : appendFunctionName(node->aggfnoid, context);
2954 472 : appendStringInfoChar(buf, '(');
2955 :
2956 : /* Add DISTINCT */
2957 472 : appendStringInfoString(buf, (node->aggdistinct != NIL) ? "DISTINCT " : "");
2958 :
2959 472 : if (AGGKIND_IS_ORDERED_SET(node->aggkind))
2960 : {
2961 : /* Add WITHIN GROUP (ORDER BY ..) */
2962 : ListCell *arg;
2963 16 : bool first = true;
2964 :
2965 : Assert(!node->aggvariadic);
2966 : Assert(node->aggorder != NIL);
2967 :
2968 36 : foreach(arg, node->aggdirectargs)
2969 : {
2970 20 : if (!first)
2971 4 : appendStringInfoString(buf, ", ");
2972 20 : first = false;
2973 :
2974 20 : deparseExpr((Expr *) lfirst(arg), context);
2975 : }
2976 :
2977 16 : appendStringInfoString(buf, ") WITHIN GROUP (ORDER BY ");
2978 16 : appendAggOrderBy(node->aggorder, node->args, context);
2979 : }
2980 : else
2981 : {
2982 : /* aggstar can be set only in zero-argument aggregates */
2983 456 : if (node->aggstar)
2984 98 : appendStringInfoChar(buf, '*');
2985 : else
2986 : {
2987 : ListCell *arg;
2988 358 : bool first = true;
2989 :
2990 : /* Add all the arguments */
2991 724 : foreach(arg, node->args)
2992 : {
2993 366 : TargetEntry *tle = (TargetEntry *) lfirst(arg);
2994 366 : Node *n = (Node *) tle->expr;
2995 :
2996 366 : if (tle->resjunk)
2997 8 : continue;
2998 :
2999 358 : if (!first)
3000 0 : appendStringInfoString(buf, ", ");
3001 358 : first = false;
3002 :
3003 : /* Add VARIADIC */
3004 358 : if (use_variadic && lnext(node->args, arg) == NULL)
3005 4 : appendStringInfoString(buf, "VARIADIC ");
3006 :
3007 358 : deparseExpr((Expr *) n, context);
3008 : }
3009 : }
3010 :
3011 : /* Add ORDER BY */
3012 456 : if (node->aggorder != NIL)
3013 : {
3014 44 : appendStringInfoString(buf, " ORDER BY ");
3015 44 : appendAggOrderBy(node->aggorder, node->args, context);
3016 : }
3017 : }
3018 :
3019 : /* Add FILTER (WHERE ..) */
3020 472 : if (node->aggfilter != NULL)
3021 : {
3022 24 : appendStringInfoString(buf, ") FILTER (WHERE ");
3023 24 : deparseExpr((Expr *) node->aggfilter, context);
3024 : }
3025 :
3026 472 : appendStringInfoChar(buf, ')');
3027 472 : }
3028 :
3029 : /*
3030 : * Append ORDER BY within aggregate function.
3031 : */
3032 : static void
3033 60 : appendAggOrderBy(List *orderList, List *targetList, deparse_expr_cxt *context)
3034 : {
3035 60 : StringInfo buf = context->buf;
3036 : ListCell *lc;
3037 60 : bool first = true;
3038 :
3039 124 : foreach(lc, orderList)
3040 : {
3041 64 : SortGroupClause *srt = (SortGroupClause *) lfirst(lc);
3042 : Node *sortexpr;
3043 : Oid sortcoltype;
3044 : TypeCacheEntry *typentry;
3045 :
3046 64 : if (!first)
3047 4 : appendStringInfoString(buf, ", ");
3048 64 : first = false;
3049 :
3050 64 : sortexpr = deparseSortGroupClause(srt->tleSortGroupRef, targetList,
3051 : false, context);
3052 64 : sortcoltype = exprType(sortexpr);
3053 : /* See whether operator is default < or > for datatype */
3054 64 : typentry = lookup_type_cache(sortcoltype,
3055 : TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
3056 64 : if (srt->sortop == typentry->lt_opr)
3057 40 : appendStringInfoString(buf, " ASC");
3058 24 : else if (srt->sortop == typentry->gt_opr)
3059 16 : appendStringInfoString(buf, " DESC");
3060 : else
3061 : {
3062 : HeapTuple opertup;
3063 : Form_pg_operator operform;
3064 :
3065 8 : appendStringInfoString(buf, " USING ");
3066 :
3067 : /* Append operator name. */
3068 8 : opertup = SearchSysCache1(OPEROID, ObjectIdGetDatum(srt->sortop));
3069 8 : if (!HeapTupleIsValid(opertup))
3070 0 : elog(ERROR, "cache lookup failed for operator %u", srt->sortop);
3071 8 : operform = (Form_pg_operator) GETSTRUCT(opertup);
3072 8 : deparseOperatorName(buf, operform);
3073 8 : ReleaseSysCache(opertup);
3074 : }
3075 :
3076 64 : if (srt->nulls_first)
3077 8 : appendStringInfoString(buf, " NULLS FIRST");
3078 : else
3079 56 : appendStringInfoString(buf, " NULLS LAST");
3080 : }
3081 60 : }
3082 :
3083 : /*
3084 : * Print the representation of a parameter to be sent to the remote side.
3085 : *
3086 : * Note: we always label the Param's type explicitly rather than relying on
3087 : * transmitting a numeric type OID in PQexecParams(). This allows us to
3088 : * avoid assuming that types have the same OIDs on the remote side as they
3089 : * do locally --- they need only have the same names.
3090 : */
3091 : static void
3092 34 : printRemoteParam(int paramindex, Oid paramtype, int32 paramtypmod,
3093 : deparse_expr_cxt *context)
3094 : {
3095 34 : StringInfo buf = context->buf;
3096 34 : char *ptypename = deparse_type_name(paramtype, paramtypmod);
3097 :
3098 34 : appendStringInfo(buf, "$%d::%s", paramindex, ptypename);
3099 34 : }
3100 :
3101 : /*
3102 : * Print the representation of a placeholder for a parameter that will be
3103 : * sent to the remote side at execution time.
3104 : *
3105 : * This is used when we're just trying to EXPLAIN the remote query.
3106 : * We don't have the actual value of the runtime parameter yet, and we don't
3107 : * want the remote planner to generate a plan that depends on such a value
3108 : * anyway. Thus, we can't do something simple like "$1::paramtype".
3109 : * Instead, we emit "((SELECT null::paramtype)::paramtype)".
3110 : * In all extant versions of Postgres, the planner will see that as an unknown
3111 : * constant value, which is what we want. This might need adjustment if we
3112 : * ever make the planner flatten scalar subqueries. Note: the reason for the
3113 : * apparently useless outer cast is to ensure that the representation as a
3114 : * whole will be parsed as an a_expr and not a select_with_parens; the latter
3115 : * would do the wrong thing in the context "x = ANY(...)".
3116 : */
3117 : static void
3118 286 : printRemotePlaceholder(Oid paramtype, int32 paramtypmod,
3119 : deparse_expr_cxt *context)
3120 : {
3121 286 : StringInfo buf = context->buf;
3122 286 : char *ptypename = deparse_type_name(paramtype, paramtypmod);
3123 :
3124 286 : appendStringInfo(buf, "((SELECT null::%s)::%s)", ptypename, ptypename);
3125 286 : }
3126 :
3127 : /*
3128 : * Deparse GROUP BY clause.
3129 : */
3130 : static void
3131 278 : appendGroupByClause(List *tlist, deparse_expr_cxt *context)
3132 : {
3133 278 : StringInfo buf = context->buf;
3134 278 : Query *query = context->root->parse;
3135 : ListCell *lc;
3136 278 : bool first = true;
3137 :
3138 : /* Nothing to be done, if there's no GROUP BY clause in the query. */
3139 278 : if (!query->groupClause)
3140 76 : return;
3141 :
3142 202 : appendStringInfoString(buf, " GROUP BY ");
3143 :
3144 : /*
3145 : * Queries with grouping sets are not pushed down, so we don't expect
3146 : * grouping sets here.
3147 : */
3148 : Assert(!query->groupingSets);
3149 :
3150 428 : foreach(lc, query->groupClause)
3151 : {
3152 226 : SortGroupClause *grp = (SortGroupClause *) lfirst(lc);
3153 :
3154 226 : if (!first)
3155 24 : appendStringInfoString(buf, ", ");
3156 226 : first = false;
3157 :
3158 226 : deparseSortGroupClause(grp->tleSortGroupRef, tlist, true, context);
3159 : }
3160 : }
3161 :
3162 : /*
3163 : * Deparse ORDER BY clause according to the given pathkeys for given base
3164 : * relation. From given pathkeys expressions belonging entirely to the given
3165 : * base relation are obtained and deparsed.
3166 : */
3167 : static void
3168 922 : appendOrderByClause(List *pathkeys, bool has_final_sort,
3169 : deparse_expr_cxt *context)
3170 : {
3171 : ListCell *lcell;
3172 : int nestlevel;
3173 922 : char *delim = " ";
3174 922 : RelOptInfo *baserel = context->scanrel;
3175 922 : StringInfo buf = context->buf;
3176 :
3177 : /* Make sure any constants in the exprs are printed portably */
3178 922 : nestlevel = set_transmission_modes();
3179 :
3180 922 : appendStringInfoString(buf, " ORDER BY");
3181 2100 : foreach(lcell, pathkeys)
3182 : {
3183 1178 : PathKey *pathkey = lfirst(lcell);
3184 : Expr *em_expr;
3185 :
3186 1178 : if (has_final_sort)
3187 : {
3188 : /*
3189 : * By construction, context->foreignrel is the input relation to
3190 : * the final sort.
3191 : */
3192 338 : em_expr = find_em_expr_for_input_target(context->root,
3193 : pathkey->pk_eclass,
3194 338 : context->foreignrel->reltarget);
3195 : }
3196 : else
3197 840 : em_expr = find_em_expr_for_rel(pathkey->pk_eclass, baserel);
3198 :
3199 : Assert(em_expr != NULL);
3200 :
3201 1178 : appendStringInfoString(buf, delim);
3202 1178 : deparseExpr(em_expr, context);
3203 1178 : if (pathkey->pk_strategy == BTLessStrategyNumber)
3204 1168 : appendStringInfoString(buf, " ASC");
3205 : else
3206 10 : appendStringInfoString(buf, " DESC");
3207 :
3208 1178 : if (pathkey->pk_nulls_first)
3209 10 : appendStringInfoString(buf, " NULLS FIRST");
3210 : else
3211 1168 : appendStringInfoString(buf, " NULLS LAST");
3212 :
3213 1178 : delim = ", ";
3214 : }
3215 922 : reset_transmission_modes(nestlevel);
3216 922 : }
3217 :
3218 : /*
3219 : * Deparse LIMIT/OFFSET clause.
3220 : */
3221 : static void
3222 178 : appendLimitClause(deparse_expr_cxt *context)
3223 : {
3224 178 : PlannerInfo *root = context->root;
3225 178 : StringInfo buf = context->buf;
3226 : int nestlevel;
3227 :
3228 : /* Make sure any constants in the exprs are printed portably */
3229 178 : nestlevel = set_transmission_modes();
3230 :
3231 178 : if (root->parse->limitCount)
3232 : {
3233 178 : appendStringInfoString(buf, " LIMIT ");
3234 178 : deparseExpr((Expr *) root->parse->limitCount, context);
3235 : }
3236 178 : if (root->parse->limitOffset)
3237 : {
3238 142 : appendStringInfoString(buf, " OFFSET ");
3239 142 : deparseExpr((Expr *) root->parse->limitOffset, context);
3240 : }
3241 :
3242 178 : reset_transmission_modes(nestlevel);
3243 178 : }
3244 :
3245 : /*
3246 : * appendFunctionName
3247 : * Deparses function name from given function oid.
3248 : */
3249 : static void
3250 524 : appendFunctionName(Oid funcid, deparse_expr_cxt *context)
3251 : {
3252 524 : StringInfo buf = context->buf;
3253 : HeapTuple proctup;
3254 : Form_pg_proc procform;
3255 : const char *proname;
3256 :
3257 524 : proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
3258 524 : if (!HeapTupleIsValid(proctup))
3259 0 : elog(ERROR, "cache lookup failed for function %u", funcid);
3260 524 : procform = (Form_pg_proc) GETSTRUCT(proctup);
3261 :
3262 : /* Print schema name only if it's not pg_catalog */
3263 524 : if (procform->pronamespace != PG_CATALOG_NAMESPACE)
3264 : {
3265 : const char *schemaname;
3266 :
3267 12 : schemaname = get_namespace_name(procform->pronamespace);
3268 12 : appendStringInfo(buf, "%s.", quote_identifier(schemaname));
3269 : }
3270 :
3271 : /* Always print the function name */
3272 524 : proname = NameStr(procform->proname);
3273 524 : appendStringInfoString(buf, quote_identifier(proname));
3274 :
3275 524 : ReleaseSysCache(proctup);
3276 524 : }
3277 :
3278 : /*
3279 : * Appends a sort or group clause.
3280 : *
3281 : * Like get_rule_sortgroupclause(), returns the expression tree, so caller
3282 : * need not find it again.
3283 : */
3284 : static Node *
3285 290 : deparseSortGroupClause(Index ref, List *tlist, bool force_colno,
3286 : deparse_expr_cxt *context)
3287 : {
3288 290 : StringInfo buf = context->buf;
3289 : TargetEntry *tle;
3290 : Expr *expr;
3291 :
3292 290 : tle = get_sortgroupref_tle(ref, tlist);
3293 290 : expr = tle->expr;
3294 :
3295 290 : if (force_colno)
3296 : {
3297 : /* Use column-number form when requested by caller. */
3298 : Assert(!tle->resjunk);
3299 226 : appendStringInfo(buf, "%d", tle->resno);
3300 : }
3301 64 : else if (expr && IsA(expr, Const))
3302 : {
3303 : /*
3304 : * Force a typecast here so that we don't emit something like "GROUP
3305 : * BY 2", which will be misconstrued as a column position rather than
3306 : * a constant.
3307 : */
3308 0 : deparseConst((Const *) expr, context, 1);
3309 : }
3310 64 : else if (!expr || IsA(expr, Var))
3311 36 : deparseExpr(expr, context);
3312 : else
3313 : {
3314 : /* Always parenthesize the expression. */
3315 28 : appendStringInfoChar(buf, '(');
3316 28 : deparseExpr(expr, context);
3317 28 : appendStringInfoChar(buf, ')');
3318 : }
3319 :
3320 290 : return (Node *) expr;
3321 : }
3322 :
3323 :
3324 : /*
3325 : * Returns true if given Var is deparsed as a subquery output column, in
3326 : * which case, *relno and *colno are set to the IDs for the relation and
3327 : * column alias to the Var provided by the subquery.
3328 : */
3329 : static bool
3330 9706 : is_subquery_var(Var *node, RelOptInfo *foreignrel, int *relno, int *colno)
3331 : {
3332 9706 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
3333 9706 : RelOptInfo *outerrel = fpinfo->outerrel;
3334 9706 : RelOptInfo *innerrel = fpinfo->innerrel;
3335 :
3336 : /* Should only be called in these cases. */
3337 : Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
3338 :
3339 : /*
3340 : * If the given relation isn't a join relation, it doesn't have any lower
3341 : * subqueries, so the Var isn't a subquery output column.
3342 : */
3343 9706 : if (!IS_JOIN_REL(foreignrel))
3344 3114 : return false;
3345 :
3346 : /*
3347 : * If the Var doesn't belong to any lower subqueries, it isn't a subquery
3348 : * output column.
3349 : */
3350 6592 : if (!bms_is_member(node->varno, fpinfo->lower_subquery_rels))
3351 6424 : return false;
3352 :
3353 168 : if (bms_is_member(node->varno, outerrel->relids))
3354 : {
3355 : /*
3356 : * If outer relation is deparsed as a subquery, the Var is an output
3357 : * column of the subquery; get the IDs for the relation/column alias.
3358 : */
3359 84 : if (fpinfo->make_outerrel_subquery)
3360 : {
3361 84 : get_relation_column_alias_ids(node, outerrel, relno, colno);
3362 84 : return true;
3363 : }
3364 :
3365 : /* Otherwise, recurse into the outer relation. */
3366 0 : return is_subquery_var(node, outerrel, relno, colno);
3367 : }
3368 : else
3369 : {
3370 : Assert(bms_is_member(node->varno, innerrel->relids));
3371 :
3372 : /*
3373 : * If inner relation is deparsed as a subquery, the Var is an output
3374 : * column of the subquery; get the IDs for the relation/column alias.
3375 : */
3376 84 : if (fpinfo->make_innerrel_subquery)
3377 : {
3378 84 : get_relation_column_alias_ids(node, innerrel, relno, colno);
3379 84 : return true;
3380 : }
3381 :
3382 : /* Otherwise, recurse into the inner relation. */
3383 0 : return is_subquery_var(node, innerrel, relno, colno);
3384 : }
3385 : }
3386 :
3387 : /*
3388 : * Get the IDs for the relation and column alias to given Var belonging to
3389 : * given relation, which are returned into *relno and *colno.
3390 : */
3391 : static void
3392 168 : get_relation_column_alias_ids(Var *node, RelOptInfo *foreignrel,
3393 : int *relno, int *colno)
3394 : {
3395 168 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
3396 : int i;
3397 : ListCell *lc;
3398 :
3399 : /* Get the relation alias ID */
3400 168 : *relno = fpinfo->relation_index;
3401 :
3402 : /* Get the column alias ID */
3403 168 : i = 1;
3404 192 : foreach(lc, foreignrel->reltarget->exprs)
3405 : {
3406 192 : if (equal(lfirst(lc), (Node *) node))
3407 : {
3408 168 : *colno = i;
3409 168 : return;
3410 : }
3411 24 : i++;
3412 : }
3413 :
3414 : /* Shouldn't get here */
3415 0 : elog(ERROR, "unexpected expression in subquery output");
3416 : }
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