Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * rewriteManip.c
4 : *
5 : * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
6 : * Portions Copyright (c) 1994, Regents of the University of California
7 : *
8 : *
9 : * IDENTIFICATION
10 : * src/backend/rewrite/rewriteManip.c
11 : *
12 : *-------------------------------------------------------------------------
13 : */
14 : #include "postgres.h"
15 :
16 : #include "catalog/pg_type.h"
17 : #include "nodes/makefuncs.h"
18 : #include "nodes/nodeFuncs.h"
19 : #include "nodes/pathnodes.h"
20 : #include "nodes/plannodes.h"
21 : #include "parser/parse_coerce.h"
22 : #include "parser/parse_relation.h"
23 : #include "parser/parsetree.h"
24 : #include "rewrite/rewriteManip.h"
25 :
26 :
27 : typedef struct
28 : {
29 : int sublevels_up;
30 : } contain_aggs_of_level_context;
31 :
32 : typedef struct
33 : {
34 : int agg_location;
35 : int sublevels_up;
36 : } locate_agg_of_level_context;
37 :
38 : typedef struct
39 : {
40 : int win_location;
41 : } locate_windowfunc_context;
42 :
43 : typedef struct
44 : {
45 : const Bitmapset *target_relids;
46 : const Bitmapset *added_relids;
47 : int sublevels_up;
48 : } add_nulling_relids_context;
49 :
50 : typedef struct
51 : {
52 : const Bitmapset *removable_relids;
53 : const Bitmapset *except_relids;
54 : int sublevels_up;
55 : } remove_nulling_relids_context;
56 :
57 : static bool contain_aggs_of_level_walker(Node *node,
58 : contain_aggs_of_level_context *context);
59 : static bool locate_agg_of_level_walker(Node *node,
60 : locate_agg_of_level_context *context);
61 : static bool contain_windowfuncs_walker(Node *node, void *context);
62 : static bool locate_windowfunc_walker(Node *node,
63 : locate_windowfunc_context *context);
64 : static bool checkExprHasSubLink_walker(Node *node, void *context);
65 : static Relids offset_relid_set(Relids relids, int offset);
66 : static Relids adjust_relid_set(Relids relids, int oldrelid, int newrelid);
67 : static Node *add_nulling_relids_mutator(Node *node,
68 : add_nulling_relids_context *context);
69 : static Node *remove_nulling_relids_mutator(Node *node,
70 : remove_nulling_relids_context *context);
71 :
72 :
73 : /*
74 : * contain_aggs_of_level -
75 : * Check if an expression contains an aggregate function call of a
76 : * specified query level.
77 : *
78 : * The objective of this routine is to detect whether there are aggregates
79 : * belonging to the given query level. Aggregates belonging to subqueries
80 : * or outer queries do NOT cause a true result. We must recurse into
81 : * subqueries to detect outer-reference aggregates that logically belong to
82 : * the specified query level.
83 : */
84 : bool
85 660 : contain_aggs_of_level(Node *node, int levelsup)
86 : {
87 : contain_aggs_of_level_context context;
88 :
89 660 : context.sublevels_up = levelsup;
90 :
91 : /*
92 : * Must be prepared to start with a Query or a bare expression tree; if
93 : * it's a Query, we don't want to increment sublevels_up.
94 : */
95 660 : return query_or_expression_tree_walker(node,
96 : contain_aggs_of_level_walker,
97 : (void *) &context,
98 : 0);
99 : }
100 :
101 : static bool
102 1136 : contain_aggs_of_level_walker(Node *node,
103 : contain_aggs_of_level_context *context)
104 : {
105 1136 : if (node == NULL)
106 138 : return false;
107 998 : if (IsA(node, Aggref))
108 : {
109 0 : if (((Aggref *) node)->agglevelsup == context->sublevels_up)
110 0 : return true; /* abort the tree traversal and return true */
111 : /* else fall through to examine argument */
112 : }
113 998 : if (IsA(node, GroupingFunc))
114 : {
115 0 : if (((GroupingFunc *) node)->agglevelsup == context->sublevels_up)
116 0 : return true;
117 : /* else fall through to examine argument */
118 : }
119 998 : if (IsA(node, Query))
120 : {
121 : /* Recurse into subselects */
122 : bool result;
123 :
124 4 : context->sublevels_up++;
125 4 : result = query_tree_walker((Query *) node,
126 : contain_aggs_of_level_walker,
127 : (void *) context, 0);
128 4 : context->sublevels_up--;
129 4 : return result;
130 : }
131 994 : return expression_tree_walker(node, contain_aggs_of_level_walker,
132 : (void *) context);
133 : }
134 :
135 : /*
136 : * locate_agg_of_level -
137 : * Find the parse location of any aggregate of the specified query level.
138 : *
139 : * Returns -1 if no such agg is in the querytree, or if they all have
140 : * unknown parse location. (The former case is probably caller error,
141 : * but we don't bother to distinguish it from the latter case.)
142 : *
143 : * Note: it might seem appropriate to merge this functionality into
144 : * contain_aggs_of_level, but that would complicate that function's API.
145 : * Currently, the only uses of this function are for error reporting,
146 : * and so shaving cycles probably isn't very important.
147 : */
148 : int
149 60 : locate_agg_of_level(Node *node, int levelsup)
150 : {
151 : locate_agg_of_level_context context;
152 :
153 60 : context.agg_location = -1; /* in case we find nothing */
154 60 : context.sublevels_up = levelsup;
155 :
156 : /*
157 : * Must be prepared to start with a Query or a bare expression tree; if
158 : * it's a Query, we don't want to increment sublevels_up.
159 : */
160 60 : (void) query_or_expression_tree_walker(node,
161 : locate_agg_of_level_walker,
162 : (void *) &context,
163 : 0);
164 :
165 60 : return context.agg_location;
166 : }
167 :
168 : static bool
169 240 : locate_agg_of_level_walker(Node *node,
170 : locate_agg_of_level_context *context)
171 : {
172 240 : if (node == NULL)
173 12 : return false;
174 228 : if (IsA(node, Aggref))
175 : {
176 54 : if (((Aggref *) node)->agglevelsup == context->sublevels_up &&
177 48 : ((Aggref *) node)->location >= 0)
178 : {
179 48 : context->agg_location = ((Aggref *) node)->location;
180 48 : return true; /* abort the tree traversal and return true */
181 : }
182 : /* else fall through to examine argument */
183 : }
184 180 : if (IsA(node, GroupingFunc))
185 : {
186 0 : if (((GroupingFunc *) node)->agglevelsup == context->sublevels_up &&
187 0 : ((GroupingFunc *) node)->location >= 0)
188 : {
189 0 : context->agg_location = ((GroupingFunc *) node)->location;
190 0 : return true; /* abort the tree traversal and return true */
191 : }
192 : }
193 180 : if (IsA(node, Query))
194 : {
195 : /* Recurse into subselects */
196 : bool result;
197 :
198 12 : context->sublevels_up++;
199 12 : result = query_tree_walker((Query *) node,
200 : locate_agg_of_level_walker,
201 : (void *) context, 0);
202 12 : context->sublevels_up--;
203 12 : return result;
204 : }
205 168 : return expression_tree_walker(node, locate_agg_of_level_walker,
206 : (void *) context);
207 : }
208 :
209 : /*
210 : * contain_windowfuncs -
211 : * Check if an expression contains a window function call of the
212 : * current query level.
213 : */
214 : bool
215 9320 : contain_windowfuncs(Node *node)
216 : {
217 : /*
218 : * Must be prepared to start with a Query or a bare expression tree; if
219 : * it's a Query, we don't want to increment sublevels_up.
220 : */
221 9320 : return query_or_expression_tree_walker(node,
222 : contain_windowfuncs_walker,
223 : NULL,
224 : 0);
225 : }
226 :
227 : static bool
228 10190 : contain_windowfuncs_walker(Node *node, void *context)
229 : {
230 10190 : if (node == NULL)
231 168 : return false;
232 10022 : if (IsA(node, WindowFunc))
233 12 : return true; /* abort the tree traversal and return true */
234 : /* Mustn't recurse into subselects */
235 10010 : return expression_tree_walker(node, contain_windowfuncs_walker,
236 : (void *) context);
237 : }
238 :
239 : /*
240 : * locate_windowfunc -
241 : * Find the parse location of any windowfunc of the current query level.
242 : *
243 : * Returns -1 if no such windowfunc is in the querytree, or if they all have
244 : * unknown parse location. (The former case is probably caller error,
245 : * but we don't bother to distinguish it from the latter case.)
246 : *
247 : * Note: it might seem appropriate to merge this functionality into
248 : * contain_windowfuncs, but that would complicate that function's API.
249 : * Currently, the only uses of this function are for error reporting,
250 : * and so shaving cycles probably isn't very important.
251 : */
252 : int
253 6 : locate_windowfunc(Node *node)
254 : {
255 : locate_windowfunc_context context;
256 :
257 6 : context.win_location = -1; /* in case we find nothing */
258 :
259 : /*
260 : * Must be prepared to start with a Query or a bare expression tree; if
261 : * it's a Query, we don't want to increment sublevels_up.
262 : */
263 6 : (void) query_or_expression_tree_walker(node,
264 : locate_windowfunc_walker,
265 : (void *) &context,
266 : 0);
267 :
268 6 : return context.win_location;
269 : }
270 :
271 : static bool
272 6 : locate_windowfunc_walker(Node *node, locate_windowfunc_context *context)
273 : {
274 6 : if (node == NULL)
275 0 : return false;
276 6 : if (IsA(node, WindowFunc))
277 : {
278 6 : if (((WindowFunc *) node)->location >= 0)
279 : {
280 6 : context->win_location = ((WindowFunc *) node)->location;
281 6 : return true; /* abort the tree traversal and return true */
282 : }
283 : /* else fall through to examine argument */
284 : }
285 : /* Mustn't recurse into subselects */
286 0 : return expression_tree_walker(node, locate_windowfunc_walker,
287 : (void *) context);
288 : }
289 :
290 : /*
291 : * checkExprHasSubLink -
292 : * Check if an expression contains a SubLink.
293 : */
294 : bool
295 103132 : checkExprHasSubLink(Node *node)
296 : {
297 : /*
298 : * If a Query is passed, examine it --- but we should not recurse into
299 : * sub-Queries that are in its rangetable or CTE list.
300 : */
301 103132 : return query_or_expression_tree_walker(node,
302 : checkExprHasSubLink_walker,
303 : NULL,
304 : QTW_IGNORE_RC_SUBQUERIES);
305 : }
306 :
307 : static bool
308 174186 : checkExprHasSubLink_walker(Node *node, void *context)
309 : {
310 174186 : if (node == NULL)
311 3576 : return false;
312 170610 : if (IsA(node, SubLink))
313 1582 : return true; /* abort the tree traversal and return true */
314 169028 : return expression_tree_walker(node, checkExprHasSubLink_walker, context);
315 : }
316 :
317 : /*
318 : * Check for MULTIEXPR Param within expression tree
319 : *
320 : * We intentionally don't descend into SubLinks: only Params at the current
321 : * query level are of interest.
322 : */
323 : static bool
324 9782 : contains_multiexpr_param(Node *node, void *context)
325 : {
326 9782 : if (node == NULL)
327 18 : return false;
328 9764 : if (IsA(node, Param))
329 : {
330 0 : if (((Param *) node)->paramkind == PARAM_MULTIEXPR)
331 0 : return true; /* abort the tree traversal and return true */
332 0 : return false;
333 : }
334 9764 : return expression_tree_walker(node, contains_multiexpr_param, context);
335 : }
336 :
337 : /*
338 : * CombineRangeTables
339 : * Adds the RTEs of 'src_rtable' into 'dst_rtable'
340 : *
341 : * This also adds the RTEPermissionInfos of 'src_perminfos' (belonging to the
342 : * RTEs in 'src_rtable') into *dst_perminfos and also updates perminfoindex of
343 : * the RTEs in 'src_rtable' to now point to the perminfos' indexes in
344 : * *dst_perminfos.
345 : *
346 : * Note that this changes both 'dst_rtable' and 'dst_perminfos' destructively,
347 : * so the caller should have better passed safe-to-modify copies.
348 : */
349 : void
350 35070 : CombineRangeTables(List **dst_rtable, List **dst_perminfos,
351 : List *src_rtable, List *src_perminfos)
352 : {
353 : ListCell *l;
354 35070 : int offset = list_length(*dst_perminfos);
355 :
356 35070 : if (offset > 0)
357 : {
358 85770 : foreach(l, src_rtable)
359 : {
360 57966 : RangeTblEntry *rte = lfirst_node(RangeTblEntry, l);
361 :
362 57966 : if (rte->perminfoindex > 0)
363 30682 : rte->perminfoindex += offset;
364 : }
365 : }
366 :
367 35070 : *dst_perminfos = list_concat(*dst_perminfos, src_perminfos);
368 35070 : *dst_rtable = list_concat(*dst_rtable, src_rtable);
369 35070 : }
370 :
371 : /*
372 : * OffsetVarNodes - adjust Vars when appending one query's RT to another
373 : *
374 : * Find all Var nodes in the given tree with varlevelsup == sublevels_up,
375 : * and increment their varno fields (rangetable indexes) by 'offset'.
376 : * The varnosyn fields are adjusted similarly. Also, adjust other nodes
377 : * that contain rangetable indexes, such as RangeTblRef and JoinExpr.
378 : *
379 : * NOTE: although this has the form of a walker, we cheat and modify the
380 : * nodes in-place. The given expression tree should have been copied
381 : * earlier to ensure that no unwanted side-effects occur!
382 : */
383 :
384 : typedef struct
385 : {
386 : int offset;
387 : int sublevels_up;
388 : } OffsetVarNodes_context;
389 :
390 : static bool
391 1830058 : OffsetVarNodes_walker(Node *node, OffsetVarNodes_context *context)
392 : {
393 1830058 : if (node == NULL)
394 550808 : return false;
395 1279250 : if (IsA(node, Var))
396 : {
397 675166 : Var *var = (Var *) node;
398 :
399 675166 : if (var->varlevelsup == context->sublevels_up)
400 : {
401 658618 : var->varno += context->offset;
402 658618 : var->varnullingrels = offset_relid_set(var->varnullingrels,
403 : context->offset);
404 658618 : if (var->varnosyn > 0)
405 658618 : var->varnosyn += context->offset;
406 : }
407 675166 : return false;
408 : }
409 604084 : if (IsA(node, CurrentOfExpr))
410 : {
411 0 : CurrentOfExpr *cexpr = (CurrentOfExpr *) node;
412 :
413 0 : if (context->sublevels_up == 0)
414 0 : cexpr->cvarno += context->offset;
415 0 : return false;
416 : }
417 604084 : if (IsA(node, RangeTblRef))
418 : {
419 51624 : RangeTblRef *rtr = (RangeTblRef *) node;
420 :
421 51624 : if (context->sublevels_up == 0)
422 47252 : rtr->rtindex += context->offset;
423 : /* the subquery itself is visited separately */
424 51624 : return false;
425 : }
426 552460 : if (IsA(node, JoinExpr))
427 : {
428 12764 : JoinExpr *j = (JoinExpr *) node;
429 :
430 12764 : if (j->rtindex && context->sublevels_up == 0)
431 12146 : j->rtindex += context->offset;
432 : /* fall through to examine children */
433 : }
434 552460 : if (IsA(node, PlaceHolderVar))
435 : {
436 416 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
437 :
438 416 : if (phv->phlevelsup == context->sublevels_up)
439 : {
440 332 : phv->phrels = offset_relid_set(phv->phrels,
441 : context->offset);
442 332 : phv->phnullingrels = offset_relid_set(phv->phnullingrels,
443 : context->offset);
444 : }
445 : /* fall through to examine children */
446 : }
447 552460 : if (IsA(node, AppendRelInfo))
448 : {
449 632 : AppendRelInfo *appinfo = (AppendRelInfo *) node;
450 :
451 632 : if (context->sublevels_up == 0)
452 : {
453 632 : appinfo->parent_relid += context->offset;
454 632 : appinfo->child_relid += context->offset;
455 : }
456 : /* fall through to examine children */
457 : }
458 : /* Shouldn't need to handle other planner auxiliary nodes here */
459 : Assert(!IsA(node, PlanRowMark));
460 : Assert(!IsA(node, SpecialJoinInfo));
461 : Assert(!IsA(node, PlaceHolderInfo));
462 : Assert(!IsA(node, MinMaxAggInfo));
463 :
464 552460 : if (IsA(node, Query))
465 : {
466 : /* Recurse into subselects */
467 : bool result;
468 :
469 3896 : context->sublevels_up++;
470 3896 : result = query_tree_walker((Query *) node, OffsetVarNodes_walker,
471 : (void *) context, 0);
472 3896 : context->sublevels_up--;
473 3896 : return result;
474 : }
475 548564 : return expression_tree_walker(node, OffsetVarNodes_walker,
476 : (void *) context);
477 : }
478 :
479 : void
480 67124 : OffsetVarNodes(Node *node, int offset, int sublevels_up)
481 : {
482 : OffsetVarNodes_context context;
483 :
484 67124 : context.offset = offset;
485 67124 : context.sublevels_up = sublevels_up;
486 :
487 : /*
488 : * Must be prepared to start with a Query or a bare expression tree; if
489 : * it's a Query, go straight to query_tree_walker to make sure that
490 : * sublevels_up doesn't get incremented prematurely.
491 : */
492 67124 : if (node && IsA(node, Query))
493 33562 : {
494 33562 : Query *qry = (Query *) node;
495 :
496 : /*
497 : * If we are starting at a Query, and sublevels_up is zero, then we
498 : * must also fix rangetable indexes in the Query itself --- namely
499 : * resultRelation, mergeTargetRelation, exclRelIndex and rowMarks
500 : * entries. sublevels_up cannot be zero when recursing into a
501 : * subquery, so there's no need to have the same logic inside
502 : * OffsetVarNodes_walker.
503 : */
504 33562 : if (sublevels_up == 0)
505 : {
506 : ListCell *l;
507 :
508 33562 : if (qry->resultRelation)
509 1230 : qry->resultRelation += offset;
510 :
511 33562 : if (qry->mergeTargetRelation)
512 0 : qry->mergeTargetRelation += offset;
513 :
514 33562 : if (qry->onConflict && qry->onConflict->exclRelIndex)
515 36 : qry->onConflict->exclRelIndex += offset;
516 :
517 33710 : foreach(l, qry->rowMarks)
518 : {
519 148 : RowMarkClause *rc = (RowMarkClause *) lfirst(l);
520 :
521 148 : rc->rti += offset;
522 : }
523 : }
524 33562 : query_tree_walker(qry, OffsetVarNodes_walker,
525 : (void *) &context, 0);
526 : }
527 : else
528 33562 : OffsetVarNodes_walker(node, &context);
529 67124 : }
530 :
531 : static Relids
532 659282 : offset_relid_set(Relids relids, int offset)
533 : {
534 659282 : Relids result = NULL;
535 : int rtindex;
536 :
537 659282 : rtindex = -1;
538 757236 : while ((rtindex = bms_next_member(relids, rtindex)) >= 0)
539 97954 : result = bms_add_member(result, rtindex + offset);
540 659282 : return result;
541 : }
542 :
543 : /*
544 : * ChangeVarNodes - adjust Var nodes for a specific change of RT index
545 : *
546 : * Find all Var nodes in the given tree belonging to a specific relation
547 : * (identified by sublevels_up and rt_index), and change their varno fields
548 : * to 'new_index'. The varnosyn fields are changed too. Also, adjust other
549 : * nodes that contain rangetable indexes, such as RangeTblRef and JoinExpr.
550 : *
551 : * NOTE: although this has the form of a walker, we cheat and modify the
552 : * nodes in-place. The given expression tree should have been copied
553 : * earlier to ensure that no unwanted side-effects occur!
554 : */
555 :
556 : typedef struct
557 : {
558 : int rt_index;
559 : int new_index;
560 : int sublevels_up;
561 : } ChangeVarNodes_context;
562 :
563 : static bool
564 263092 : ChangeVarNodes_walker(Node *node, ChangeVarNodes_context *context)
565 : {
566 263092 : if (node == NULL)
567 98228 : return false;
568 164864 : if (IsA(node, Var))
569 : {
570 44818 : Var *var = (Var *) node;
571 :
572 44818 : if (var->varlevelsup == context->sublevels_up)
573 : {
574 41740 : if (var->varno == context->rt_index)
575 30540 : var->varno = context->new_index;
576 41740 : var->varnullingrels = adjust_relid_set(var->varnullingrels,
577 : context->rt_index,
578 : context->new_index);
579 41740 : if (var->varnosyn == context->rt_index)
580 30540 : var->varnosyn = context->new_index;
581 : }
582 44818 : return false;
583 : }
584 120046 : if (IsA(node, CurrentOfExpr))
585 : {
586 0 : CurrentOfExpr *cexpr = (CurrentOfExpr *) node;
587 :
588 0 : if (context->sublevels_up == 0 &&
589 0 : cexpr->cvarno == context->rt_index)
590 0 : cexpr->cvarno = context->new_index;
591 0 : return false;
592 : }
593 120046 : if (IsA(node, RangeTblRef))
594 : {
595 5080 : RangeTblRef *rtr = (RangeTblRef *) node;
596 :
597 5080 : if (context->sublevels_up == 0 &&
598 3016 : rtr->rtindex == context->rt_index)
599 1652 : rtr->rtindex = context->new_index;
600 : /* the subquery itself is visited separately */
601 5080 : return false;
602 : }
603 114966 : if (IsA(node, JoinExpr))
604 : {
605 0 : JoinExpr *j = (JoinExpr *) node;
606 :
607 0 : if (context->sublevels_up == 0 &&
608 0 : j->rtindex == context->rt_index)
609 0 : j->rtindex = context->new_index;
610 : /* fall through to examine children */
611 : }
612 114966 : if (IsA(node, PlaceHolderVar))
613 : {
614 0 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
615 :
616 0 : if (phv->phlevelsup == context->sublevels_up)
617 : {
618 0 : phv->phrels = adjust_relid_set(phv->phrels,
619 : context->rt_index,
620 : context->new_index);
621 0 : phv->phnullingrels = adjust_relid_set(phv->phnullingrels,
622 : context->rt_index,
623 : context->new_index);
624 : }
625 : /* fall through to examine children */
626 : }
627 114966 : if (IsA(node, PlanRowMark))
628 : {
629 0 : PlanRowMark *rowmark = (PlanRowMark *) node;
630 :
631 0 : if (context->sublevels_up == 0)
632 : {
633 0 : if (rowmark->rti == context->rt_index)
634 0 : rowmark->rti = context->new_index;
635 0 : if (rowmark->prti == context->rt_index)
636 0 : rowmark->prti = context->new_index;
637 : }
638 0 : return false;
639 : }
640 114966 : if (IsA(node, AppendRelInfo))
641 : {
642 0 : AppendRelInfo *appinfo = (AppendRelInfo *) node;
643 :
644 0 : if (context->sublevels_up == 0)
645 : {
646 0 : if (appinfo->parent_relid == context->rt_index)
647 0 : appinfo->parent_relid = context->new_index;
648 0 : if (appinfo->child_relid == context->rt_index)
649 0 : appinfo->child_relid = context->new_index;
650 : }
651 : /* fall through to examine children */
652 : }
653 : /* Shouldn't need to handle other planner auxiliary nodes here */
654 : Assert(!IsA(node, SpecialJoinInfo));
655 : Assert(!IsA(node, PlaceHolderInfo));
656 : Assert(!IsA(node, MinMaxAggInfo));
657 :
658 114966 : if (IsA(node, Query))
659 : {
660 : /* Recurse into subselects */
661 : bool result;
662 :
663 2070 : context->sublevels_up++;
664 2070 : result = query_tree_walker((Query *) node, ChangeVarNodes_walker,
665 : (void *) context, 0);
666 2070 : context->sublevels_up--;
667 2070 : return result;
668 : }
669 112896 : return expression_tree_walker(node, ChangeVarNodes_walker,
670 : (void *) context);
671 : }
672 :
673 : void
674 22420 : ChangeVarNodes(Node *node, int rt_index, int new_index, int sublevels_up)
675 : {
676 : ChangeVarNodes_context context;
677 :
678 22420 : context.rt_index = rt_index;
679 22420 : context.new_index = new_index;
680 22420 : context.sublevels_up = sublevels_up;
681 :
682 : /*
683 : * Must be prepared to start with a Query or a bare expression tree; if
684 : * it's a Query, go straight to query_tree_walker to make sure that
685 : * sublevels_up doesn't get incremented prematurely.
686 : */
687 22420 : if (node && IsA(node, Query))
688 4412 : {
689 4412 : Query *qry = (Query *) node;
690 :
691 : /*
692 : * If we are starting at a Query, and sublevels_up is zero, then we
693 : * must also fix rangetable indexes in the Query itself --- namely
694 : * resultRelation, mergeTargetRelation, exclRelIndex and rowMarks
695 : * entries. sublevels_up cannot be zero when recursing into a
696 : * subquery, so there's no need to have the same logic inside
697 : * ChangeVarNodes_walker.
698 : */
699 4412 : if (sublevels_up == 0)
700 : {
701 : ListCell *l;
702 :
703 4412 : if (qry->resultRelation == rt_index)
704 3074 : qry->resultRelation = new_index;
705 :
706 4412 : if (qry->mergeTargetRelation == rt_index)
707 792 : qry->mergeTargetRelation = new_index;
708 :
709 : /* this is unlikely to ever be used, but ... */
710 4412 : if (qry->onConflict && qry->onConflict->exclRelIndex == rt_index)
711 0 : qry->onConflict->exclRelIndex = new_index;
712 :
713 4424 : foreach(l, qry->rowMarks)
714 : {
715 12 : RowMarkClause *rc = (RowMarkClause *) lfirst(l);
716 :
717 12 : if (rc->rti == rt_index)
718 0 : rc->rti = new_index;
719 : }
720 : }
721 4412 : query_tree_walker(qry, ChangeVarNodes_walker,
722 : (void *) &context, 0);
723 : }
724 : else
725 18008 : ChangeVarNodes_walker(node, &context);
726 22420 : }
727 :
728 : /*
729 : * Substitute newrelid for oldrelid in a Relid set
730 : *
731 : * Note: some extensions may pass a special varno such as INDEX_VAR for
732 : * oldrelid. bms_is_member won't like that, but we should tolerate it.
733 : * (Perhaps newrelid could also be a special varno, but there had better
734 : * not be a reason to inject that into a nullingrels or phrels set.)
735 : */
736 : static Relids
737 41740 : adjust_relid_set(Relids relids, int oldrelid, int newrelid)
738 : {
739 41740 : if (!IS_SPECIAL_VARNO(oldrelid) && bms_is_member(oldrelid, relids))
740 : {
741 : /* Ensure we have a modifiable copy */
742 0 : relids = bms_copy(relids);
743 : /* Remove old, add new */
744 0 : relids = bms_del_member(relids, oldrelid);
745 0 : relids = bms_add_member(relids, newrelid);
746 : }
747 41740 : return relids;
748 : }
749 :
750 : /*
751 : * IncrementVarSublevelsUp - adjust Var nodes when pushing them down in tree
752 : *
753 : * Find all Var nodes in the given tree having varlevelsup >= min_sublevels_up,
754 : * and add delta_sublevels_up to their varlevelsup value. This is needed when
755 : * an expression that's correct for some nesting level is inserted into a
756 : * subquery. Ordinarily the initial call has min_sublevels_up == 0 so that
757 : * all Vars are affected. The point of min_sublevels_up is that we can
758 : * increment it when we recurse into a sublink, so that local variables in
759 : * that sublink are not affected, only outer references to vars that belong
760 : * to the expression's original query level or parents thereof.
761 : *
762 : * Likewise for other nodes containing levelsup fields, such as Aggref.
763 : *
764 : * NOTE: although this has the form of a walker, we cheat and modify the
765 : * Var nodes in-place. The given expression tree should have been copied
766 : * earlier to ensure that no unwanted side-effects occur!
767 : */
768 :
769 : typedef struct
770 : {
771 : int delta_sublevels_up;
772 : int min_sublevels_up;
773 : } IncrementVarSublevelsUp_context;
774 :
775 : static bool
776 2115348 : IncrementVarSublevelsUp_walker(Node *node,
777 : IncrementVarSublevelsUp_context *context)
778 : {
779 2115348 : if (node == NULL)
780 627492 : return false;
781 1487856 : if (IsA(node, Var))
782 : {
783 731174 : Var *var = (Var *) node;
784 :
785 731174 : if (var->varlevelsup >= context->min_sublevels_up)
786 8890 : var->varlevelsup += context->delta_sublevels_up;
787 731174 : return false; /* done here */
788 : }
789 756682 : if (IsA(node, CurrentOfExpr))
790 : {
791 : /* this should not happen */
792 0 : if (context->min_sublevels_up == 0)
793 0 : elog(ERROR, "cannot push down CurrentOfExpr");
794 0 : return false;
795 : }
796 756682 : if (IsA(node, Aggref))
797 : {
798 2202 : Aggref *agg = (Aggref *) node;
799 :
800 2202 : if (agg->agglevelsup >= context->min_sublevels_up)
801 70 : agg->agglevelsup += context->delta_sublevels_up;
802 : /* fall through to recurse into argument */
803 : }
804 756682 : if (IsA(node, GroupingFunc))
805 : {
806 64 : GroupingFunc *grp = (GroupingFunc *) node;
807 :
808 64 : if (grp->agglevelsup >= context->min_sublevels_up)
809 64 : grp->agglevelsup += context->delta_sublevels_up;
810 : /* fall through to recurse into argument */
811 : }
812 756682 : if (IsA(node, PlaceHolderVar))
813 : {
814 772 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
815 :
816 772 : if (phv->phlevelsup >= context->min_sublevels_up)
817 440 : phv->phlevelsup += context->delta_sublevels_up;
818 : /* fall through to recurse into argument */
819 : }
820 756682 : if (IsA(node, RangeTblEntry))
821 : {
822 77840 : RangeTblEntry *rte = (RangeTblEntry *) node;
823 :
824 77840 : if (rte->rtekind == RTE_CTE)
825 : {
826 3826 : if (rte->ctelevelsup >= context->min_sublevels_up)
827 3796 : rte->ctelevelsup += context->delta_sublevels_up;
828 : }
829 77840 : return false; /* allow range_table_walker to continue */
830 : }
831 678842 : if (IsA(node, Query))
832 : {
833 : /* Recurse into subselects */
834 : bool result;
835 :
836 9184 : context->min_sublevels_up++;
837 9184 : result = query_tree_walker((Query *) node,
838 : IncrementVarSublevelsUp_walker,
839 : (void *) context,
840 : QTW_EXAMINE_RTES_BEFORE);
841 9184 : context->min_sublevels_up--;
842 9184 : return result;
843 : }
844 669658 : return expression_tree_walker(node, IncrementVarSublevelsUp_walker,
845 : (void *) context);
846 : }
847 :
848 : void
849 70564 : IncrementVarSublevelsUp(Node *node, int delta_sublevels_up,
850 : int min_sublevels_up)
851 : {
852 : IncrementVarSublevelsUp_context context;
853 :
854 70564 : context.delta_sublevels_up = delta_sublevels_up;
855 70564 : context.min_sublevels_up = min_sublevels_up;
856 :
857 : /*
858 : * Must be prepared to start with a Query or a bare expression tree; if
859 : * it's a Query, we don't want to increment sublevels_up.
860 : */
861 70564 : query_or_expression_tree_walker(node,
862 : IncrementVarSublevelsUp_walker,
863 : (void *) &context,
864 : QTW_EXAMINE_RTES_BEFORE);
865 70564 : }
866 :
867 : /*
868 : * IncrementVarSublevelsUp_rtable -
869 : * Same as IncrementVarSublevelsUp, but to be invoked on a range table.
870 : */
871 : void
872 1546 : IncrementVarSublevelsUp_rtable(List *rtable, int delta_sublevels_up,
873 : int min_sublevels_up)
874 : {
875 : IncrementVarSublevelsUp_context context;
876 :
877 1546 : context.delta_sublevels_up = delta_sublevels_up;
878 1546 : context.min_sublevels_up = min_sublevels_up;
879 :
880 1546 : range_table_walker(rtable,
881 : IncrementVarSublevelsUp_walker,
882 : (void *) &context,
883 : QTW_EXAMINE_RTES_BEFORE);
884 1546 : }
885 :
886 :
887 : /*
888 : * rangeTableEntry_used - detect whether an RTE is referenced somewhere
889 : * in var nodes or join or setOp trees of a query or expression.
890 : */
891 :
892 : typedef struct
893 : {
894 : int rt_index;
895 : int sublevels_up;
896 : } rangeTableEntry_used_context;
897 :
898 : static bool
899 3388860 : rangeTableEntry_used_walker(Node *node,
900 : rangeTableEntry_used_context *context)
901 : {
902 3388860 : if (node == NULL)
903 637158 : return false;
904 2751702 : if (IsA(node, Var))
905 : {
906 797146 : Var *var = (Var *) node;
907 :
908 797146 : if (var->varlevelsup == context->sublevels_up &&
909 1265518 : (var->varno == context->rt_index ||
910 498734 : bms_is_member(context->rt_index, var->varnullingrels)))
911 268050 : return true;
912 529096 : return false;
913 : }
914 1954556 : if (IsA(node, CurrentOfExpr))
915 : {
916 12 : CurrentOfExpr *cexpr = (CurrentOfExpr *) node;
917 :
918 12 : if (context->sublevels_up == 0 &&
919 12 : cexpr->cvarno == context->rt_index)
920 0 : return true;
921 12 : return false;
922 : }
923 1954544 : if (IsA(node, RangeTblRef))
924 : {
925 115716 : RangeTblRef *rtr = (RangeTblRef *) node;
926 :
927 115716 : if (rtr->rtindex == context->rt_index &&
928 61248 : context->sublevels_up == 0)
929 59130 : return true;
930 : /* the subquery itself is visited separately */
931 56586 : return false;
932 : }
933 1838828 : if (IsA(node, JoinExpr))
934 : {
935 37002 : JoinExpr *j = (JoinExpr *) node;
936 :
937 37002 : if (j->rtindex == context->rt_index &&
938 66 : context->sublevels_up == 0)
939 0 : return true;
940 : /* fall through to examine children */
941 : }
942 : /* Shouldn't need to handle planner auxiliary nodes here */
943 : Assert(!IsA(node, PlaceHolderVar));
944 : Assert(!IsA(node, PlanRowMark));
945 : Assert(!IsA(node, SpecialJoinInfo));
946 : Assert(!IsA(node, AppendRelInfo));
947 : Assert(!IsA(node, PlaceHolderInfo));
948 : Assert(!IsA(node, MinMaxAggInfo));
949 :
950 1838828 : if (IsA(node, Query))
951 : {
952 : /* Recurse into subselects */
953 : bool result;
954 :
955 12592 : context->sublevels_up++;
956 12592 : result = query_tree_walker((Query *) node, rangeTableEntry_used_walker,
957 : (void *) context, 0);
958 12592 : context->sublevels_up--;
959 12592 : return result;
960 : }
961 1826236 : return expression_tree_walker(node, rangeTableEntry_used_walker,
962 : (void *) context);
963 : }
964 :
965 : bool
966 342274 : rangeTableEntry_used(Node *node, int rt_index, int sublevels_up)
967 : {
968 : rangeTableEntry_used_context context;
969 :
970 342274 : context.rt_index = rt_index;
971 342274 : context.sublevels_up = sublevels_up;
972 :
973 : /*
974 : * Must be prepared to start with a Query or a bare expression tree; if
975 : * it's a Query, we don't want to increment sublevels_up.
976 : */
977 342274 : return query_or_expression_tree_walker(node,
978 : rangeTableEntry_used_walker,
979 : (void *) &context,
980 : 0);
981 : }
982 :
983 :
984 : /*
985 : * If the given Query is an INSERT ... SELECT construct, extract and
986 : * return the sub-Query node that represents the SELECT part. Otherwise
987 : * return the given Query.
988 : *
989 : * If subquery_ptr is not NULL, then *subquery_ptr is set to the location
990 : * of the link to the SELECT subquery inside parsetree, or NULL if not an
991 : * INSERT ... SELECT.
992 : *
993 : * This is a hack needed because transformations on INSERT ... SELECTs that
994 : * appear in rule actions should be applied to the source SELECT, not to the
995 : * INSERT part. Perhaps this can be cleaned up with redesigned querytrees.
996 : */
997 : Query *
998 3386 : getInsertSelectQuery(Query *parsetree, Query ***subquery_ptr)
999 : {
1000 : Query *selectquery;
1001 : RangeTblEntry *selectrte;
1002 : RangeTblRef *rtr;
1003 :
1004 3386 : if (subquery_ptr)
1005 1338 : *subquery_ptr = NULL;
1006 :
1007 3386 : if (parsetree == NULL)
1008 0 : return parsetree;
1009 3386 : if (parsetree->commandType != CMD_INSERT)
1010 1422 : return parsetree;
1011 :
1012 : /*
1013 : * Currently, this is ONLY applied to rule-action queries, and so we
1014 : * expect to find the OLD and NEW placeholder entries in the given query.
1015 : * If they're not there, it must be an INSERT/SELECT in which they've been
1016 : * pushed down to the SELECT.
1017 : */
1018 1964 : if (list_length(parsetree->rtable) >= 2 &&
1019 1964 : strcmp(rt_fetch(PRS2_OLD_VARNO, parsetree->rtable)->eref->aliasname,
1020 1788 : "old") == 0 &&
1021 1788 : strcmp(rt_fetch(PRS2_NEW_VARNO, parsetree->rtable)->eref->aliasname,
1022 : "new") == 0)
1023 1788 : return parsetree;
1024 : Assert(parsetree->jointree && IsA(parsetree->jointree, FromExpr));
1025 176 : if (list_length(parsetree->jointree->fromlist) != 1)
1026 0 : elog(ERROR, "expected to find SELECT subquery");
1027 176 : rtr = (RangeTblRef *) linitial(parsetree->jointree->fromlist);
1028 176 : if (!IsA(rtr, RangeTblRef))
1029 0 : elog(ERROR, "expected to find SELECT subquery");
1030 176 : selectrte = rt_fetch(rtr->rtindex, parsetree->rtable);
1031 176 : if (!(selectrte->rtekind == RTE_SUBQUERY &&
1032 176 : selectrte->subquery &&
1033 176 : IsA(selectrte->subquery, Query) &&
1034 176 : selectrte->subquery->commandType == CMD_SELECT))
1035 0 : elog(ERROR, "expected to find SELECT subquery");
1036 176 : selectquery = selectrte->subquery;
1037 176 : if (list_length(selectquery->rtable) >= 2 &&
1038 176 : strcmp(rt_fetch(PRS2_OLD_VARNO, selectquery->rtable)->eref->aliasname,
1039 176 : "old") == 0 &&
1040 176 : strcmp(rt_fetch(PRS2_NEW_VARNO, selectquery->rtable)->eref->aliasname,
1041 : "new") == 0)
1042 : {
1043 176 : if (subquery_ptr)
1044 60 : *subquery_ptr = &(selectrte->subquery);
1045 176 : return selectquery;
1046 : }
1047 0 : elog(ERROR, "could not find rule placeholders");
1048 : return NULL; /* not reached */
1049 : }
1050 :
1051 :
1052 : /*
1053 : * Add the given qualifier condition to the query's WHERE clause
1054 : */
1055 : void
1056 3566 : AddQual(Query *parsetree, Node *qual)
1057 : {
1058 : Node *copy;
1059 :
1060 3566 : if (qual == NULL)
1061 1674 : return;
1062 :
1063 1892 : if (parsetree->commandType == CMD_UTILITY)
1064 : {
1065 : /*
1066 : * There's noplace to put the qual on a utility statement.
1067 : *
1068 : * If it's a NOTIFY, silently ignore the qual; this means that the
1069 : * NOTIFY will execute, whether or not there are any qualifying rows.
1070 : * While clearly wrong, this is much more useful than refusing to
1071 : * execute the rule at all, and extra NOTIFY events are harmless for
1072 : * typical uses of NOTIFY.
1073 : *
1074 : * If it isn't a NOTIFY, error out, since unconditional execution of
1075 : * other utility stmts is unlikely to be wanted. (This case is not
1076 : * currently allowed anyway, but keep the test for safety.)
1077 : */
1078 0 : if (parsetree->utilityStmt && IsA(parsetree->utilityStmt, NotifyStmt))
1079 0 : return;
1080 : else
1081 0 : ereport(ERROR,
1082 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1083 : errmsg("conditional utility statements are not implemented")));
1084 : }
1085 :
1086 1892 : if (parsetree->setOperations != NULL)
1087 : {
1088 : /*
1089 : * There's noplace to put the qual on a setop statement, either. (This
1090 : * could be fixed, but right now the planner simply ignores any qual
1091 : * condition on a setop query.)
1092 : */
1093 0 : ereport(ERROR,
1094 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1095 : errmsg("conditional UNION/INTERSECT/EXCEPT statements are not implemented")));
1096 : }
1097 :
1098 : /* INTERSECT wants the original, but we need to copy - Jan */
1099 1892 : copy = copyObject(qual);
1100 :
1101 1892 : parsetree->jointree->quals = make_and_qual(parsetree->jointree->quals,
1102 : copy);
1103 :
1104 : /*
1105 : * We had better not have stuck an aggregate into the WHERE clause.
1106 : */
1107 : Assert(!contain_aggs_of_level(copy, 0));
1108 :
1109 : /*
1110 : * Make sure query is marked correctly if added qual has sublinks. Need
1111 : * not search qual when query is already marked.
1112 : */
1113 1892 : if (!parsetree->hasSubLinks)
1114 1886 : parsetree->hasSubLinks = checkExprHasSubLink(copy);
1115 : }
1116 :
1117 :
1118 : /*
1119 : * Invert the given clause and add it to the WHERE qualifications of the
1120 : * given querytree. Inversion means "x IS NOT TRUE", not just "NOT x",
1121 : * else we will do the wrong thing when x evaluates to NULL.
1122 : */
1123 : void
1124 444 : AddInvertedQual(Query *parsetree, Node *qual)
1125 : {
1126 : BooleanTest *invqual;
1127 :
1128 444 : if (qual == NULL)
1129 0 : return;
1130 :
1131 : /* Need not copy input qual, because AddQual will... */
1132 444 : invqual = makeNode(BooleanTest);
1133 444 : invqual->arg = (Expr *) qual;
1134 444 : invqual->booltesttype = IS_NOT_TRUE;
1135 444 : invqual->location = -1;
1136 :
1137 444 : AddQual(parsetree, (Node *) invqual);
1138 : }
1139 :
1140 :
1141 : /*
1142 : * add_nulling_relids() finds Vars and PlaceHolderVars that belong to any
1143 : * of the target_relids, and adds added_relids to their varnullingrels
1144 : * and phnullingrels fields.
1145 : */
1146 : Node *
1147 4682 : add_nulling_relids(Node *node,
1148 : const Bitmapset *target_relids,
1149 : const Bitmapset *added_relids)
1150 : {
1151 : add_nulling_relids_context context;
1152 :
1153 4682 : context.target_relids = target_relids;
1154 4682 : context.added_relids = added_relids;
1155 4682 : context.sublevels_up = 0;
1156 4682 : return query_or_expression_tree_mutator(node,
1157 : add_nulling_relids_mutator,
1158 : &context,
1159 : 0);
1160 : }
1161 :
1162 : static Node *
1163 23518 : add_nulling_relids_mutator(Node *node,
1164 : add_nulling_relids_context *context)
1165 : {
1166 23518 : if (node == NULL)
1167 0 : return NULL;
1168 23518 : if (IsA(node, Var))
1169 : {
1170 9268 : Var *var = (Var *) node;
1171 :
1172 18536 : if (var->varlevelsup == context->sublevels_up &&
1173 9268 : bms_is_member(var->varno, context->target_relids))
1174 : {
1175 4736 : Relids newnullingrels = bms_union(var->varnullingrels,
1176 : context->added_relids);
1177 :
1178 : /* Copy the Var ... */
1179 4736 : var = copyObject(var);
1180 : /* ... and replace the copy's varnullingrels field */
1181 4736 : var->varnullingrels = newnullingrels;
1182 4736 : return (Node *) var;
1183 : }
1184 : /* Otherwise fall through to copy the Var normally */
1185 : }
1186 14250 : else if (IsA(node, PlaceHolderVar))
1187 : {
1188 6 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
1189 :
1190 12 : if (phv->phlevelsup == context->sublevels_up &&
1191 6 : bms_overlap(phv->phrels, context->target_relids))
1192 : {
1193 6 : Relids newnullingrels = bms_union(phv->phnullingrels,
1194 : context->added_relids);
1195 :
1196 : /*
1197 : * We don't modify the contents of the PHV's expression, only add
1198 : * to phnullingrels. This corresponds to assuming that the PHV
1199 : * will be evaluated at the same level as before, then perhaps be
1200 : * nulled as it bubbles up. Hence, just flat-copy the node ...
1201 : */
1202 6 : phv = makeNode(PlaceHolderVar);
1203 6 : memcpy(phv, node, sizeof(PlaceHolderVar));
1204 : /* ... and replace the copy's phnullingrels field */
1205 6 : phv->phnullingrels = newnullingrels;
1206 6 : return (Node *) phv;
1207 : }
1208 : /* Otherwise fall through to copy the PlaceHolderVar normally */
1209 : }
1210 14244 : else if (IsA(node, Query))
1211 : {
1212 : /* Recurse into RTE or sublink subquery */
1213 : Query *newnode;
1214 :
1215 0 : context->sublevels_up++;
1216 0 : newnode = query_tree_mutator((Query *) node,
1217 : add_nulling_relids_mutator,
1218 : (void *) context,
1219 : 0);
1220 0 : context->sublevels_up--;
1221 0 : return (Node *) newnode;
1222 : }
1223 18776 : return expression_tree_mutator(node, add_nulling_relids_mutator,
1224 : (void *) context);
1225 : }
1226 :
1227 : /*
1228 : * remove_nulling_relids() removes mentions of the specified RT index(es)
1229 : * in Var.varnullingrels and PlaceHolderVar.phnullingrels fields within
1230 : * the given expression, except in nodes belonging to rels listed in
1231 : * except_relids.
1232 : */
1233 : Node *
1234 7912 : remove_nulling_relids(Node *node,
1235 : const Bitmapset *removable_relids,
1236 : const Bitmapset *except_relids)
1237 : {
1238 : remove_nulling_relids_context context;
1239 :
1240 7912 : context.removable_relids = removable_relids;
1241 7912 : context.except_relids = except_relids;
1242 7912 : context.sublevels_up = 0;
1243 7912 : return query_or_expression_tree_mutator(node,
1244 : remove_nulling_relids_mutator,
1245 : &context,
1246 : 0);
1247 : }
1248 :
1249 : static Node *
1250 145066 : remove_nulling_relids_mutator(Node *node,
1251 : remove_nulling_relids_context *context)
1252 : {
1253 145066 : if (node == NULL)
1254 38690 : return NULL;
1255 106376 : if (IsA(node, Var))
1256 : {
1257 28642 : Var *var = (Var *) node;
1258 :
1259 28642 : if (var->varlevelsup == context->sublevels_up &&
1260 51150 : !bms_is_member(var->varno, context->except_relids) &&
1261 25528 : bms_overlap(var->varnullingrels, context->removable_relids))
1262 : {
1263 : /* Copy the Var ... */
1264 8222 : var = copyObject(var);
1265 : /* ... and replace the copy's varnullingrels field */
1266 8222 : var->varnullingrels = bms_difference(var->varnullingrels,
1267 : context->removable_relids);
1268 8222 : return (Node *) var;
1269 : }
1270 : /* Otherwise fall through to copy the Var normally */
1271 : }
1272 77734 : else if (IsA(node, PlaceHolderVar))
1273 : {
1274 438 : PlaceHolderVar *phv = (PlaceHolderVar *) node;
1275 :
1276 438 : if (phv->phlevelsup == context->sublevels_up &&
1277 438 : !bms_overlap(phv->phrels, context->except_relids))
1278 : {
1279 : /*
1280 : * Note: it might seem desirable to remove the PHV altogether if
1281 : * phnullingrels goes to empty. Currently we dare not do that
1282 : * because we use PHVs in some cases to enforce separate identity
1283 : * of subexpressions; see wrap_non_vars usages in prepjointree.c.
1284 : */
1285 : /* Copy the PlaceHolderVar and mutate what's below ... */
1286 : phv = (PlaceHolderVar *)
1287 438 : expression_tree_mutator(node,
1288 : remove_nulling_relids_mutator,
1289 : (void *) context);
1290 : /* ... and replace the copy's phnullingrels field */
1291 438 : phv->phnullingrels = bms_difference(phv->phnullingrels,
1292 : context->removable_relids);
1293 : /* We must also update phrels, if it contains a removable RTI */
1294 438 : phv->phrels = bms_difference(phv->phrels,
1295 : context->removable_relids);
1296 : Assert(!bms_is_empty(phv->phrels));
1297 438 : return (Node *) phv;
1298 : }
1299 : /* Otherwise fall through to copy the PlaceHolderVar normally */
1300 : }
1301 77296 : else if (IsA(node, Query))
1302 : {
1303 : /* Recurse into RTE or sublink subquery */
1304 : Query *newnode;
1305 :
1306 160 : context->sublevels_up++;
1307 160 : newnode = query_tree_mutator((Query *) node,
1308 : remove_nulling_relids_mutator,
1309 : (void *) context,
1310 : 0);
1311 160 : context->sublevels_up--;
1312 160 : return (Node *) newnode;
1313 : }
1314 97556 : return expression_tree_mutator(node, remove_nulling_relids_mutator,
1315 : (void *) context);
1316 : }
1317 :
1318 :
1319 : /*
1320 : * replace_rte_variables() finds all Vars in an expression tree
1321 : * that reference a particular RTE, and replaces them with substitute
1322 : * expressions obtained from a caller-supplied callback function.
1323 : *
1324 : * When invoking replace_rte_variables on a portion of a Query, pass the
1325 : * address of the containing Query's hasSubLinks field as outer_hasSubLinks.
1326 : * Otherwise, pass NULL, but inserting a SubLink into a non-Query expression
1327 : * will then cause an error.
1328 : *
1329 : * Note: the business with inserted_sublink is needed to update hasSubLinks
1330 : * in subqueries when the replacement adds a subquery inside a subquery.
1331 : * Messy, isn't it? We do not need to do similar pushups for hasAggs,
1332 : * because it isn't possible for this transformation to insert a level-zero
1333 : * aggregate reference into a subquery --- it could only insert outer aggs.
1334 : * Likewise for hasWindowFuncs.
1335 : *
1336 : * Note: usually, we'd not expose the mutator function or context struct
1337 : * for a function like this. We do so because callbacks often find it
1338 : * convenient to recurse directly to the mutator on sub-expressions of
1339 : * what they will return.
1340 : */
1341 : Node *
1342 168184 : replace_rte_variables(Node *node, int target_varno, int sublevels_up,
1343 : replace_rte_variables_callback callback,
1344 : void *callback_arg,
1345 : bool *outer_hasSubLinks)
1346 : {
1347 : Node *result;
1348 : replace_rte_variables_context context;
1349 :
1350 168184 : context.callback = callback;
1351 168184 : context.callback_arg = callback_arg;
1352 168184 : context.target_varno = target_varno;
1353 168184 : context.sublevels_up = sublevels_up;
1354 :
1355 : /*
1356 : * We try to initialize inserted_sublink to true if there is no need to
1357 : * detect new sublinks because the query already has some.
1358 : */
1359 168184 : if (node && IsA(node, Query))
1360 4604 : context.inserted_sublink = ((Query *) node)->hasSubLinks;
1361 163580 : else if (outer_hasSubLinks)
1362 163580 : context.inserted_sublink = *outer_hasSubLinks;
1363 : else
1364 0 : context.inserted_sublink = false;
1365 :
1366 : /*
1367 : * Must be prepared to start with a Query or a bare expression tree; if
1368 : * it's a Query, we don't want to increment sublevels_up.
1369 : */
1370 168184 : result = query_or_expression_tree_mutator(node,
1371 : replace_rte_variables_mutator,
1372 : (void *) &context,
1373 : 0);
1374 :
1375 168178 : if (context.inserted_sublink)
1376 : {
1377 17236 : if (result && IsA(result, Query))
1378 96 : ((Query *) result)->hasSubLinks = true;
1379 17140 : else if (outer_hasSubLinks)
1380 17140 : *outer_hasSubLinks = true;
1381 : else
1382 0 : elog(ERROR, "replace_rte_variables inserted a SubLink, but has noplace to record it");
1383 : }
1384 :
1385 168178 : return result;
1386 : }
1387 :
1388 : Node *
1389 749842 : replace_rte_variables_mutator(Node *node,
1390 : replace_rte_variables_context *context)
1391 : {
1392 749842 : if (node == NULL)
1393 232906 : return NULL;
1394 516936 : if (IsA(node, Var))
1395 : {
1396 189466 : Var *var = (Var *) node;
1397 :
1398 189466 : if (var->varno == context->target_varno &&
1399 111108 : var->varlevelsup == context->sublevels_up)
1400 : {
1401 : /* Found a matching variable, make the substitution */
1402 : Node *newnode;
1403 :
1404 103692 : newnode = context->callback(var, context);
1405 : /* Detect if we are adding a sublink to query */
1406 103692 : if (!context->inserted_sublink)
1407 95244 : context->inserted_sublink = checkExprHasSubLink(newnode);
1408 103692 : return newnode;
1409 : }
1410 : /* otherwise fall through to copy the var normally */
1411 : }
1412 327470 : else if (IsA(node, CurrentOfExpr))
1413 : {
1414 6 : CurrentOfExpr *cexpr = (CurrentOfExpr *) node;
1415 :
1416 6 : if (cexpr->cvarno == context->target_varno &&
1417 6 : context->sublevels_up == 0)
1418 : {
1419 : /*
1420 : * We get here if a WHERE CURRENT OF expression turns out to apply
1421 : * to a view. Someday we might be able to translate the
1422 : * expression to apply to an underlying table of the view, but
1423 : * right now it's not implemented.
1424 : */
1425 6 : ereport(ERROR,
1426 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1427 : errmsg("WHERE CURRENT OF on a view is not implemented")));
1428 : }
1429 : /* otherwise fall through to copy the expr normally */
1430 : }
1431 327464 : else if (IsA(node, Query))
1432 : {
1433 : /* Recurse into RTE subquery or not-yet-planned sublink subquery */
1434 : Query *newnode;
1435 : bool save_inserted_sublink;
1436 :
1437 2470 : context->sublevels_up++;
1438 2470 : save_inserted_sublink = context->inserted_sublink;
1439 2470 : context->inserted_sublink = ((Query *) node)->hasSubLinks;
1440 2470 : newnode = query_tree_mutator((Query *) node,
1441 : replace_rte_variables_mutator,
1442 : (void *) context,
1443 : 0);
1444 2470 : newnode->hasSubLinks |= context->inserted_sublink;
1445 2470 : context->inserted_sublink = save_inserted_sublink;
1446 2470 : context->sublevels_up--;
1447 2470 : return (Node *) newnode;
1448 : }
1449 410768 : return expression_tree_mutator(node, replace_rte_variables_mutator,
1450 : (void *) context);
1451 : }
1452 :
1453 :
1454 : /*
1455 : * map_variable_attnos() finds all user-column Vars in an expression tree
1456 : * that reference a particular RTE, and adjusts their varattnos according
1457 : * to the given mapping array (varattno n is replaced by attno_map[n-1]).
1458 : * Vars for system columns are not modified.
1459 : *
1460 : * A zero in the mapping array represents a dropped column, which should not
1461 : * appear in the expression.
1462 : *
1463 : * If the expression tree contains a whole-row Var for the target RTE,
1464 : * *found_whole_row is set to true. In addition, if to_rowtype is
1465 : * not InvalidOid, we replace the Var with a Var of that vartype, inserting
1466 : * a ConvertRowtypeExpr to map back to the rowtype expected by the expression.
1467 : * (Therefore, to_rowtype had better be a child rowtype of the rowtype of the
1468 : * RTE we're changing references to.) Callers that don't provide to_rowtype
1469 : * should report an error if *found_whole_row is true; we don't do that here
1470 : * because we don't know exactly what wording for the error message would
1471 : * be most appropriate. The caller will be aware of the context.
1472 : *
1473 : * This could be built using replace_rte_variables and a callback function,
1474 : * but since we don't ever need to insert sublinks, replace_rte_variables is
1475 : * overly complicated.
1476 : */
1477 :
1478 : typedef struct
1479 : {
1480 : int target_varno; /* RTE index to search for */
1481 : int sublevels_up; /* (current) nesting depth */
1482 : const AttrMap *attno_map; /* map array for user attnos */
1483 : Oid to_rowtype; /* change whole-row Vars to this type */
1484 : bool *found_whole_row; /* output flag */
1485 : } map_variable_attnos_context;
1486 :
1487 : static Node *
1488 114446 : map_variable_attnos_mutator(Node *node,
1489 : map_variable_attnos_context *context)
1490 : {
1491 114446 : if (node == NULL)
1492 1104 : return NULL;
1493 113342 : if (IsA(node, Var))
1494 : {
1495 25924 : Var *var = (Var *) node;
1496 :
1497 25924 : if (var->varno == context->target_varno &&
1498 25708 : var->varlevelsup == context->sublevels_up)
1499 : {
1500 : /* Found a matching variable, make the substitution */
1501 25708 : Var *newvar = (Var *) palloc(sizeof(Var));
1502 25708 : int attno = var->varattno;
1503 :
1504 25708 : *newvar = *var; /* initially copy all fields of the Var */
1505 :
1506 25708 : if (attno > 0)
1507 : {
1508 : /* user-defined column, replace attno */
1509 25582 : if (attno > context->attno_map->maplen ||
1510 25582 : context->attno_map->attnums[attno - 1] == 0)
1511 0 : elog(ERROR, "unexpected varattno %d in expression to be mapped",
1512 : attno);
1513 25582 : newvar->varattno = context->attno_map->attnums[attno - 1];
1514 : /* If the syntactic referent is same RTE, fix it too */
1515 25582 : if (newvar->varnosyn == context->target_varno)
1516 25504 : newvar->varattnosyn = newvar->varattno;
1517 : }
1518 126 : else if (attno == 0)
1519 : {
1520 : /* whole-row variable, warn caller */
1521 54 : *(context->found_whole_row) = true;
1522 :
1523 : /* If the caller expects us to convert the Var, do so. */
1524 54 : if (OidIsValid(context->to_rowtype) &&
1525 48 : context->to_rowtype != var->vartype)
1526 : {
1527 : ConvertRowtypeExpr *r;
1528 :
1529 : /* This certainly won't work for a RECORD variable. */
1530 : Assert(var->vartype != RECORDOID);
1531 :
1532 : /* Var itself is changed to the requested type. */
1533 48 : newvar->vartype = context->to_rowtype;
1534 :
1535 : /*
1536 : * Add a conversion node on top to convert back to the
1537 : * original type expected by the expression.
1538 : */
1539 48 : r = makeNode(ConvertRowtypeExpr);
1540 48 : r->arg = (Expr *) newvar;
1541 48 : r->resulttype = var->vartype;
1542 48 : r->convertformat = COERCE_IMPLICIT_CAST;
1543 48 : r->location = -1;
1544 :
1545 48 : return (Node *) r;
1546 : }
1547 : }
1548 25660 : return (Node *) newvar;
1549 : }
1550 : /* otherwise fall through to copy the var normally */
1551 : }
1552 87418 : else if (IsA(node, ConvertRowtypeExpr))
1553 : {
1554 36 : ConvertRowtypeExpr *r = (ConvertRowtypeExpr *) node;
1555 36 : Var *var = (Var *) r->arg;
1556 :
1557 : /*
1558 : * If this is coercing a whole-row Var that we need to convert, then
1559 : * just convert the Var without adding an extra ConvertRowtypeExpr.
1560 : * Effectively we're simplifying var::parenttype::grandparenttype into
1561 : * just var::grandparenttype. This avoids building stacks of CREs if
1562 : * this function is applied repeatedly.
1563 : */
1564 36 : if (IsA(var, Var) &&
1565 24 : var->varno == context->target_varno &&
1566 18 : var->varlevelsup == context->sublevels_up &&
1567 18 : var->varattno == 0 &&
1568 18 : OidIsValid(context->to_rowtype) &&
1569 18 : context->to_rowtype != var->vartype)
1570 : {
1571 : ConvertRowtypeExpr *newnode;
1572 18 : Var *newvar = (Var *) palloc(sizeof(Var));
1573 :
1574 : /* whole-row variable, warn caller */
1575 18 : *(context->found_whole_row) = true;
1576 :
1577 18 : *newvar = *var; /* initially copy all fields of the Var */
1578 :
1579 : /* This certainly won't work for a RECORD variable. */
1580 : Assert(var->vartype != RECORDOID);
1581 :
1582 : /* Var itself is changed to the requested type. */
1583 18 : newvar->vartype = context->to_rowtype;
1584 :
1585 18 : newnode = (ConvertRowtypeExpr *) palloc(sizeof(ConvertRowtypeExpr));
1586 18 : *newnode = *r; /* initially copy all fields of the CRE */
1587 18 : newnode->arg = (Expr *) newvar;
1588 :
1589 18 : return (Node *) newnode;
1590 : }
1591 : /* otherwise fall through to process the expression normally */
1592 : }
1593 87382 : else if (IsA(node, Query))
1594 : {
1595 : /* Recurse into RTE subquery or not-yet-planned sublink subquery */
1596 : Query *newnode;
1597 :
1598 0 : context->sublevels_up++;
1599 0 : newnode = query_tree_mutator((Query *) node,
1600 : map_variable_attnos_mutator,
1601 : (void *) context,
1602 : 0);
1603 0 : context->sublevels_up--;
1604 0 : return (Node *) newnode;
1605 : }
1606 87616 : return expression_tree_mutator(node, map_variable_attnos_mutator,
1607 : (void *) context);
1608 : }
1609 :
1610 : Node *
1611 9812 : map_variable_attnos(Node *node,
1612 : int target_varno, int sublevels_up,
1613 : const AttrMap *attno_map,
1614 : Oid to_rowtype, bool *found_whole_row)
1615 : {
1616 : map_variable_attnos_context context;
1617 :
1618 9812 : context.target_varno = target_varno;
1619 9812 : context.sublevels_up = sublevels_up;
1620 9812 : context.attno_map = attno_map;
1621 9812 : context.to_rowtype = to_rowtype;
1622 9812 : context.found_whole_row = found_whole_row;
1623 :
1624 9812 : *found_whole_row = false;
1625 :
1626 : /*
1627 : * Must be prepared to start with a Query or a bare expression tree; if
1628 : * it's a Query, we don't want to increment sublevels_up.
1629 : */
1630 9812 : return query_or_expression_tree_mutator(node,
1631 : map_variable_attnos_mutator,
1632 : (void *) &context,
1633 : 0);
1634 : }
1635 :
1636 :
1637 : /*
1638 : * ReplaceVarsFromTargetList - replace Vars with items from a targetlist
1639 : *
1640 : * Vars matching target_varno and sublevels_up are replaced by the
1641 : * entry with matching resno from targetlist, if there is one.
1642 : *
1643 : * If there is no matching resno for such a Var, the action depends on the
1644 : * nomatch_option:
1645 : * REPLACEVARS_REPORT_ERROR: throw an error
1646 : * REPLACEVARS_CHANGE_VARNO: change Var's varno to nomatch_varno
1647 : * REPLACEVARS_SUBSTITUTE_NULL: replace Var with a NULL Const of same type
1648 : *
1649 : * The caller must also provide target_rte, the RTE describing the target
1650 : * relation. This is needed to handle whole-row Vars referencing the target.
1651 : * We expand such Vars into RowExpr constructs.
1652 : *
1653 : * outer_hasSubLinks works the same as for replace_rte_variables().
1654 : */
1655 :
1656 : typedef struct
1657 : {
1658 : RangeTblEntry *target_rte;
1659 : List *targetlist;
1660 : ReplaceVarsNoMatchOption nomatch_option;
1661 : int nomatch_varno;
1662 : } ReplaceVarsFromTargetList_context;
1663 :
1664 : static Node *
1665 8700 : ReplaceVarsFromTargetList_callback(Var *var,
1666 : replace_rte_variables_context *context)
1667 : {
1668 8700 : ReplaceVarsFromTargetList_context *rcon = (ReplaceVarsFromTargetList_context *) context->callback_arg;
1669 : TargetEntry *tle;
1670 :
1671 8700 : if (var->varattno == InvalidAttrNumber)
1672 : {
1673 : /* Must expand whole-tuple reference into RowExpr */
1674 : RowExpr *rowexpr;
1675 : List *colnames;
1676 : List *fields;
1677 :
1678 : /*
1679 : * If generating an expansion for a var of a named rowtype (ie, this
1680 : * is a plain relation RTE), then we must include dummy items for
1681 : * dropped columns. If the var is RECORD (ie, this is a JOIN), then
1682 : * omit dropped columns. In the latter case, attach column names to
1683 : * the RowExpr for use of the executor and ruleutils.c.
1684 : */
1685 54 : expandRTE(rcon->target_rte,
1686 54 : var->varno, var->varlevelsup, var->location,
1687 54 : (var->vartype != RECORDOID),
1688 : &colnames, &fields);
1689 : /* Adjust the generated per-field Vars... */
1690 54 : fields = (List *) replace_rte_variables_mutator((Node *) fields,
1691 : context);
1692 54 : rowexpr = makeNode(RowExpr);
1693 54 : rowexpr->args = fields;
1694 54 : rowexpr->row_typeid = var->vartype;
1695 54 : rowexpr->row_format = COERCE_IMPLICIT_CAST;
1696 54 : rowexpr->colnames = (var->vartype == RECORDOID) ? colnames : NIL;
1697 54 : rowexpr->location = var->location;
1698 :
1699 54 : return (Node *) rowexpr;
1700 : }
1701 :
1702 : /* Normal case referencing one targetlist element */
1703 8646 : tle = get_tle_by_resno(rcon->targetlist, var->varattno);
1704 :
1705 8646 : if (tle == NULL || tle->resjunk)
1706 : {
1707 : /* Failed to find column in targetlist */
1708 390 : switch (rcon->nomatch_option)
1709 : {
1710 0 : case REPLACEVARS_REPORT_ERROR:
1711 : /* fall through, throw error below */
1712 0 : break;
1713 :
1714 240 : case REPLACEVARS_CHANGE_VARNO:
1715 240 : var = (Var *) copyObject(var);
1716 240 : var->varno = rcon->nomatch_varno;
1717 : /* we leave the syntactic referent alone */
1718 240 : return (Node *) var;
1719 :
1720 150 : case REPLACEVARS_SUBSTITUTE_NULL:
1721 :
1722 : /*
1723 : * If Var is of domain type, we should add a CoerceToDomain
1724 : * node, in case there is a NOT NULL domain constraint.
1725 : */
1726 150 : return coerce_to_domain((Node *) makeNullConst(var->vartype,
1727 : var->vartypmod,
1728 : var->varcollid),
1729 : InvalidOid, -1,
1730 : var->vartype,
1731 : COERCION_IMPLICIT,
1732 : COERCE_IMPLICIT_CAST,
1733 : -1,
1734 : false);
1735 : }
1736 0 : elog(ERROR, "could not find replacement targetlist entry for attno %d",
1737 : var->varattno);
1738 : return NULL; /* keep compiler quiet */
1739 : }
1740 : else
1741 : {
1742 : /* Make a copy of the tlist item to return */
1743 8256 : Expr *newnode = copyObject(tle->expr);
1744 :
1745 : /* Must adjust varlevelsup if tlist item is from higher query */
1746 8256 : if (var->varlevelsup > 0)
1747 162 : IncrementVarSublevelsUp((Node *) newnode, var->varlevelsup, 0);
1748 :
1749 : /*
1750 : * Check to see if the tlist item contains a PARAM_MULTIEXPR Param,
1751 : * and throw error if so. This case could only happen when expanding
1752 : * an ON UPDATE rule's NEW variable and the referenced tlist item in
1753 : * the original UPDATE command is part of a multiple assignment. There
1754 : * seems no practical way to handle such cases without multiple
1755 : * evaluation of the multiple assignment's sub-select, which would
1756 : * create semantic oddities that users of rules would probably prefer
1757 : * not to cope with. So treat it as an unimplemented feature.
1758 : */
1759 8256 : if (contains_multiexpr_param((Node *) newnode, NULL))
1760 0 : ereport(ERROR,
1761 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1762 : errmsg("NEW variables in ON UPDATE rules cannot reference columns that are part of a multiple assignment in the subject UPDATE command")));
1763 :
1764 8256 : return (Node *) newnode;
1765 : }
1766 : }
1767 :
1768 : Node *
1769 5854 : ReplaceVarsFromTargetList(Node *node,
1770 : int target_varno, int sublevels_up,
1771 : RangeTblEntry *target_rte,
1772 : List *targetlist,
1773 : ReplaceVarsNoMatchOption nomatch_option,
1774 : int nomatch_varno,
1775 : bool *outer_hasSubLinks)
1776 : {
1777 : ReplaceVarsFromTargetList_context context;
1778 :
1779 5854 : context.target_rte = target_rte;
1780 5854 : context.targetlist = targetlist;
1781 5854 : context.nomatch_option = nomatch_option;
1782 5854 : context.nomatch_varno = nomatch_varno;
1783 :
1784 5854 : return replace_rte_variables(node, target_varno, sublevels_up,
1785 : ReplaceVarsFromTargetList_callback,
1786 : (void *) &context,
1787 : outer_hasSubLinks);
1788 : }
|
