Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * rewriteHandler.c
4 : * Primary module of query rewriter.
5 : *
6 : * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : * IDENTIFICATION
10 : * src/backend/rewrite/rewriteHandler.c
11 : *
12 : * NOTES
13 : * Some of the terms used in this file are of historic nature: "retrieve"
14 : * was the PostQUEL keyword for what today is SELECT. "RIR" stands for
15 : * "Retrieve-Instead-Retrieve", that is an ON SELECT DO INSTEAD SELECT rule
16 : * (which has to be unconditional and where only one rule can exist on each
17 : * relation).
18 : *
19 : *-------------------------------------------------------------------------
20 : */
21 : #include "postgres.h"
22 :
23 : #include "access/relation.h"
24 : #include "access/sysattr.h"
25 : #include "access/table.h"
26 : #include "catalog/dependency.h"
27 : #include "catalog/partition.h"
28 : #include "commands/trigger.h"
29 : #include "executor/executor.h"
30 : #include "foreign/fdwapi.h"
31 : #include "miscadmin.h"
32 : #include "nodes/makefuncs.h"
33 : #include "nodes/nodeFuncs.h"
34 : #include "optimizer/optimizer.h"
35 : #include "parser/analyze.h"
36 : #include "parser/parse_coerce.h"
37 : #include "parser/parse_relation.h"
38 : #include "parser/parsetree.h"
39 : #include "rewrite/rewriteDefine.h"
40 : #include "rewrite/rewriteHandler.h"
41 : #include "rewrite/rewriteManip.h"
42 : #include "rewrite/rewriteSearchCycle.h"
43 : #include "rewrite/rowsecurity.h"
44 : #include "utils/builtins.h"
45 : #include "utils/lsyscache.h"
46 : #include "utils/rel.h"
47 :
48 :
49 : /* We use a list of these to detect recursion in RewriteQuery */
50 : typedef struct rewrite_event
51 : {
52 : Oid relation; /* OID of relation having rules */
53 : CmdType event; /* type of rule being fired */
54 : } rewrite_event;
55 :
56 : typedef struct acquireLocksOnSubLinks_context
57 : {
58 : bool for_execute; /* AcquireRewriteLocks' forExecute param */
59 : } acquireLocksOnSubLinks_context;
60 :
61 : static bool acquireLocksOnSubLinks(Node *node,
62 : acquireLocksOnSubLinks_context *context);
63 : static Query *rewriteRuleAction(Query *parsetree,
64 : Query *rule_action,
65 : Node *rule_qual,
66 : int rt_index,
67 : CmdType event,
68 : bool *returning_flag);
69 : static List *adjustJoinTreeList(Query *parsetree, bool removert, int rt_index);
70 : static List *rewriteTargetListIU(List *targetList,
71 : CmdType commandType,
72 : OverridingKind override,
73 : Relation target_relation,
74 : RangeTblEntry *values_rte,
75 : int values_rte_index,
76 : Bitmapset **unused_values_attrnos);
77 : static TargetEntry *process_matched_tle(TargetEntry *src_tle,
78 : TargetEntry *prior_tle,
79 : const char *attrName);
80 : static Node *get_assignment_input(Node *node);
81 : static Bitmapset *findDefaultOnlyColumns(RangeTblEntry *rte);
82 : static bool rewriteValuesRTE(Query *parsetree, RangeTblEntry *rte, int rti,
83 : Relation target_relation,
84 : Bitmapset *unused_cols);
85 : static void rewriteValuesRTEToNulls(Query *parsetree, RangeTblEntry *rte);
86 : static void markQueryForLocking(Query *qry, Node *jtnode,
87 : LockClauseStrength strength, LockWaitPolicy waitPolicy,
88 : bool pushedDown);
89 : static List *matchLocks(CmdType event, Relation relation,
90 : int varno, Query *parsetree, bool *hasUpdate);
91 : static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
92 : static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
93 :
94 :
95 : /*
96 : * AcquireRewriteLocks -
97 : * Acquire suitable locks on all the relations mentioned in the Query.
98 : * These locks will ensure that the relation schemas don't change under us
99 : * while we are rewriting, planning, and executing the query.
100 : *
101 : * Caution: this may modify the querytree, therefore caller should usually
102 : * have done a copyObject() to make a writable copy of the querytree in the
103 : * current memory context.
104 : *
105 : * forExecute indicates that the query is about to be executed. If so,
106 : * we'll acquire the lock modes specified in the RTE rellockmode fields.
107 : * If forExecute is false, AccessShareLock is acquired on all relations.
108 : * This case is suitable for ruleutils.c, for example, where we only need
109 : * schema stability and we don't intend to actually modify any relations.
110 : *
111 : * forUpdatePushedDown indicates that a pushed-down FOR [KEY] UPDATE/SHARE
112 : * applies to the current subquery, requiring all rels to be opened with at
113 : * least RowShareLock. This should always be false at the top of the
114 : * recursion. When it is true, we adjust RTE rellockmode fields to reflect
115 : * the higher lock level. This flag is ignored if forExecute is false.
116 : *
117 : * A secondary purpose of this routine is to fix up JOIN RTE references to
118 : * dropped columns (see details below). Such RTEs are modified in-place.
119 : *
120 : * This processing can, and for efficiency's sake should, be skipped when the
121 : * querytree has just been built by the parser: parse analysis already got
122 : * all the same locks we'd get here, and the parser will have omitted dropped
123 : * columns from JOINs to begin with. But we must do this whenever we are
124 : * dealing with a querytree produced earlier than the current command.
125 : *
126 : * About JOINs and dropped columns: although the parser never includes an
127 : * already-dropped column in a JOIN RTE's alias var list, it is possible for
128 : * such a list in a stored rule to include references to dropped columns.
129 : * (If the column is not explicitly referenced anywhere else in the query,
130 : * the dependency mechanism won't consider it used by the rule and so won't
131 : * prevent the column drop.) To support get_rte_attribute_is_dropped(), we
132 : * replace join alias vars that reference dropped columns with null pointers.
133 : *
134 : * (In PostgreSQL 8.0, we did not do this processing but instead had
135 : * get_rte_attribute_is_dropped() recurse to detect dropped columns in joins.
136 : * That approach had horrible performance unfortunately; in particular
137 : * construction of a nested join was O(N^2) in the nesting depth.)
138 : */
139 : void
140 31976 : AcquireRewriteLocks(Query *parsetree,
141 : bool forExecute,
142 : bool forUpdatePushedDown)
143 : {
144 : ListCell *l;
145 : int rt_index;
146 : acquireLocksOnSubLinks_context context;
147 :
148 31976 : context.for_execute = forExecute;
149 :
150 : /*
151 : * First, process RTEs of the current query level.
152 : */
153 31976 : rt_index = 0;
154 90714 : foreach(l, parsetree->rtable)
155 : {
156 58738 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
157 : Relation rel;
158 : LOCKMODE lockmode;
159 : List *newaliasvars;
160 : Index curinputvarno;
161 : RangeTblEntry *curinputrte;
162 : ListCell *ll;
163 :
164 58738 : ++rt_index;
165 58738 : switch (rte->rtekind)
166 : {
167 36566 : case RTE_RELATION:
168 :
169 : /*
170 : * Grab the appropriate lock type for the relation, and do not
171 : * release it until end of transaction. This protects the
172 : * rewriter, planner, and executor against schema changes
173 : * mid-query.
174 : *
175 : * If forExecute is false, ignore rellockmode and just use
176 : * AccessShareLock.
177 : */
178 36566 : if (!forExecute)
179 7000 : lockmode = AccessShareLock;
180 29566 : else if (forUpdatePushedDown)
181 : {
182 : /* Upgrade RTE's lock mode to reflect pushed-down lock */
183 96 : if (rte->rellockmode == AccessShareLock)
184 96 : rte->rellockmode = RowShareLock;
185 96 : lockmode = rte->rellockmode;
186 : }
187 : else
188 29470 : lockmode = rte->rellockmode;
189 :
190 36566 : rel = table_open(rte->relid, lockmode);
191 :
192 : /*
193 : * While we have the relation open, update the RTE's relkind,
194 : * just in case it changed since this rule was made.
195 : */
196 36566 : rte->relkind = rel->rd_rel->relkind;
197 :
198 36566 : table_close(rel, NoLock);
199 36566 : break;
200 :
201 12698 : case RTE_JOIN:
202 :
203 : /*
204 : * Scan the join's alias var list to see if any columns have
205 : * been dropped, and if so replace those Vars with null
206 : * pointers.
207 : *
208 : * Since a join has only two inputs, we can expect to see
209 : * multiple references to the same input RTE; optimize away
210 : * multiple fetches.
211 : */
212 12698 : newaliasvars = NIL;
213 12698 : curinputvarno = 0;
214 12698 : curinputrte = NULL;
215 482768 : foreach(ll, rte->joinaliasvars)
216 : {
217 470070 : Var *aliasitem = (Var *) lfirst(ll);
218 470070 : Var *aliasvar = aliasitem;
219 :
220 : /* Look through any implicit coercion */
221 470070 : aliasvar = (Var *) strip_implicit_coercions((Node *) aliasvar);
222 :
223 : /*
224 : * If the list item isn't a simple Var, then it must
225 : * represent a merged column, ie a USING column, and so it
226 : * couldn't possibly be dropped, since it's referenced in
227 : * the join clause. (Conceivably it could also be a null
228 : * pointer already? But that's OK too.)
229 : */
230 470070 : if (aliasvar && IsA(aliasvar, Var))
231 : {
232 : /*
233 : * The elements of an alias list have to refer to
234 : * earlier RTEs of the same rtable, because that's the
235 : * order the planner builds things in. So we already
236 : * processed the referenced RTE, and so it's safe to
237 : * use get_rte_attribute_is_dropped on it. (This might
238 : * not hold after rewriting or planning, but it's OK
239 : * to assume here.)
240 : */
241 : Assert(aliasvar->varlevelsup == 0);
242 469896 : if (aliasvar->varno != curinputvarno)
243 : {
244 33336 : curinputvarno = aliasvar->varno;
245 33336 : if (curinputvarno >= rt_index)
246 0 : elog(ERROR, "unexpected varno %d in JOIN RTE %d",
247 : curinputvarno, rt_index);
248 33336 : curinputrte = rt_fetch(curinputvarno,
249 : parsetree->rtable);
250 : }
251 469896 : if (get_rte_attribute_is_dropped(curinputrte,
252 469896 : aliasvar->varattno))
253 : {
254 : /* Replace the join alias item with a NULL */
255 6 : aliasitem = NULL;
256 : }
257 : }
258 470070 : newaliasvars = lappend(newaliasvars, aliasitem);
259 : }
260 12698 : rte->joinaliasvars = newaliasvars;
261 12698 : break;
262 :
263 2076 : case RTE_SUBQUERY:
264 :
265 : /*
266 : * The subquery RTE itself is all right, but we have to
267 : * recurse to process the represented subquery.
268 : */
269 2076 : AcquireRewriteLocks(rte->subquery,
270 : forExecute,
271 4152 : (forUpdatePushedDown ||
272 2076 : get_parse_rowmark(parsetree, rt_index) != NULL));
273 2076 : break;
274 :
275 7398 : default:
276 : /* ignore other types of RTEs */
277 7398 : break;
278 : }
279 : }
280 :
281 : /* Recurse into subqueries in WITH */
282 32146 : foreach(l, parsetree->cteList)
283 : {
284 170 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(l);
285 :
286 170 : AcquireRewriteLocks((Query *) cte->ctequery, forExecute, false);
287 : }
288 :
289 : /*
290 : * Recurse into sublink subqueries, too. But we already did the ones in
291 : * the rtable and cteList.
292 : */
293 31976 : if (parsetree->hasSubLinks)
294 1698 : query_tree_walker(parsetree, acquireLocksOnSubLinks, &context,
295 : QTW_IGNORE_RC_SUBQUERIES);
296 31976 : }
297 :
298 : /*
299 : * Walker to find sublink subqueries for AcquireRewriteLocks
300 : */
301 : static bool
302 122052 : acquireLocksOnSubLinks(Node *node, acquireLocksOnSubLinks_context *context)
303 : {
304 122052 : if (node == NULL)
305 28028 : return false;
306 94024 : if (IsA(node, SubLink))
307 : {
308 3816 : SubLink *sub = (SubLink *) node;
309 :
310 : /* Do what we came for */
311 3816 : AcquireRewriteLocks((Query *) sub->subselect,
312 3816 : context->for_execute,
313 : false);
314 : /* Fall through to process lefthand args of SubLink */
315 : }
316 :
317 : /*
318 : * Do NOT recurse into Query nodes, because AcquireRewriteLocks already
319 : * processed subselects of subselects for us.
320 : */
321 94024 : return expression_tree_walker(node, acquireLocksOnSubLinks, context);
322 : }
323 :
324 :
325 : /*
326 : * rewriteRuleAction -
327 : * Rewrite the rule action with appropriate qualifiers (taken from
328 : * the triggering query).
329 : *
330 : * Input arguments:
331 : * parsetree - original query
332 : * rule_action - one action (query) of a rule
333 : * rule_qual - WHERE condition of rule, or NULL if unconditional
334 : * rt_index - RT index of result relation in original query
335 : * event - type of rule event
336 : * Output arguments:
337 : * *returning_flag - set true if we rewrite RETURNING clause in rule_action
338 : * (must be initialized to false)
339 : * Return value:
340 : * rewritten form of rule_action
341 : */
342 : static Query *
343 1344 : rewriteRuleAction(Query *parsetree,
344 : Query *rule_action,
345 : Node *rule_qual,
346 : int rt_index,
347 : CmdType event,
348 : bool *returning_flag)
349 : {
350 : int current_varno,
351 : new_varno;
352 : int rt_length;
353 : Query *sub_action;
354 : Query **sub_action_ptr;
355 : acquireLocksOnSubLinks_context context;
356 : ListCell *lc;
357 :
358 1344 : context.for_execute = true;
359 :
360 : /*
361 : * Make modifiable copies of rule action and qual (what we're passed are
362 : * the stored versions in the relcache; don't touch 'em!).
363 : */
364 1344 : rule_action = copyObject(rule_action);
365 1344 : rule_qual = copyObject(rule_qual);
366 :
367 : /*
368 : * Acquire necessary locks and fix any deleted JOIN RTE entries.
369 : */
370 1344 : AcquireRewriteLocks(rule_action, true, false);
371 1344 : (void) acquireLocksOnSubLinks(rule_qual, &context);
372 :
373 1344 : current_varno = rt_index;
374 1344 : rt_length = list_length(parsetree->rtable);
375 1344 : new_varno = PRS2_NEW_VARNO + rt_length;
376 :
377 : /*
378 : * Adjust rule action and qual to offset its varnos, so that we can merge
379 : * its rtable with the main parsetree's rtable.
380 : *
381 : * If the rule action is an INSERT...SELECT, the OLD/NEW rtable entries
382 : * will be in the SELECT part, and we have to modify that rather than the
383 : * top-level INSERT (kluge!).
384 : */
385 1344 : sub_action = getInsertSelectQuery(rule_action, &sub_action_ptr);
386 :
387 1344 : OffsetVarNodes((Node *) sub_action, rt_length, 0);
388 1344 : OffsetVarNodes(rule_qual, rt_length, 0);
389 : /* but references to OLD should point at original rt_index */
390 1344 : ChangeVarNodes((Node *) sub_action,
391 : PRS2_OLD_VARNO + rt_length, rt_index, 0);
392 1344 : ChangeVarNodes(rule_qual,
393 : PRS2_OLD_VARNO + rt_length, rt_index, 0);
394 :
395 : /*
396 : * Mark any subquery RTEs in the rule action as LATERAL if they contain
397 : * Vars referring to the current query level (references to NEW/OLD).
398 : * Those really are lateral references, but we've historically not
399 : * required users to mark such subqueries with LATERAL explicitly. But
400 : * the planner will complain if such Vars exist in a non-LATERAL subquery,
401 : * so we have to fix things up here.
402 : */
403 5322 : foreach(lc, sub_action->rtable)
404 : {
405 3978 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
406 :
407 3990 : if (rte->rtekind == RTE_SUBQUERY && !rte->lateral &&
408 12 : contain_vars_of_level((Node *) rte->subquery, 1))
409 12 : rte->lateral = true;
410 : }
411 :
412 : /*
413 : * Generate expanded rtable consisting of main parsetree's rtable plus
414 : * rule action's rtable; this becomes the complete rtable for the rule
415 : * action. Some of the entries may be unused after we finish rewriting,
416 : * but we leave them all in place to avoid having to adjust the query's
417 : * varnos. RT entries that are not referenced in the completed jointree
418 : * will be ignored by the planner, so they do not affect query semantics.
419 : *
420 : * Also merge RTEPermissionInfo lists to ensure that all permissions are
421 : * checked correctly.
422 : *
423 : * If the rule is INSTEAD, then the original query won't be executed at
424 : * all, and so its rteperminfos must be preserved so that the executor
425 : * will do the correct permissions checks on the relations referenced in
426 : * it. This allows us to check that the caller has, say, insert-permission
427 : * on a view, when the view is not semantically referenced at all in the
428 : * resulting query.
429 : *
430 : * When a rule is not INSTEAD, the permissions checks done using the
431 : * copied entries will be redundant with those done during execution of
432 : * the original query, but we don't bother to treat that case differently.
433 : *
434 : * NOTE: because planner will destructively alter rtable and rteperminfos,
435 : * we must ensure that rule action's lists are separate and shares no
436 : * substructure with the main query's lists. Hence do a deep copy here
437 : * for both.
438 : */
439 : {
440 1344 : List *rtable_tail = sub_action->rtable;
441 1344 : List *perminfos_tail = sub_action->rteperminfos;
442 :
443 : /*
444 : * RewriteQuery relies on the fact that RT entries from the original
445 : * query appear at the start of the expanded rtable, so we put the
446 : * action's original table at the end of the list.
447 : */
448 1344 : sub_action->rtable = copyObject(parsetree->rtable);
449 1344 : sub_action->rteperminfos = copyObject(parsetree->rteperminfos);
450 1344 : CombineRangeTables(&sub_action->rtable, &sub_action->rteperminfos,
451 : rtable_tail, perminfos_tail);
452 : }
453 :
454 : /*
455 : * There could have been some SubLinks in parsetree's rtable, in which
456 : * case we'd better mark the sub_action correctly.
457 : */
458 1344 : if (parsetree->hasSubLinks && !sub_action->hasSubLinks)
459 : {
460 66 : foreach(lc, parsetree->rtable)
461 : {
462 48 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
463 :
464 48 : switch (rte->rtekind)
465 : {
466 42 : case RTE_RELATION:
467 42 : sub_action->hasSubLinks =
468 42 : checkExprHasSubLink((Node *) rte->tablesample);
469 42 : break;
470 0 : case RTE_FUNCTION:
471 0 : sub_action->hasSubLinks =
472 0 : checkExprHasSubLink((Node *) rte->functions);
473 0 : break;
474 0 : case RTE_TABLEFUNC:
475 0 : sub_action->hasSubLinks =
476 0 : checkExprHasSubLink((Node *) rte->tablefunc);
477 0 : break;
478 0 : case RTE_VALUES:
479 0 : sub_action->hasSubLinks =
480 0 : checkExprHasSubLink((Node *) rte->values_lists);
481 0 : break;
482 6 : default:
483 : /* other RTE types don't contain bare expressions */
484 6 : break;
485 : }
486 48 : sub_action->hasSubLinks |=
487 48 : checkExprHasSubLink((Node *) rte->securityQuals);
488 48 : if (sub_action->hasSubLinks)
489 6 : break; /* no need to keep scanning rtable */
490 : }
491 : }
492 :
493 : /*
494 : * Also, we might have absorbed some RTEs with RLS conditions into the
495 : * sub_action. If so, mark it as hasRowSecurity, whether or not those
496 : * RTEs will be referenced after we finish rewriting. (Note: currently
497 : * this is a no-op because RLS conditions aren't added till later, but it
498 : * seems like good future-proofing to do this anyway.)
499 : */
500 1344 : sub_action->hasRowSecurity |= parsetree->hasRowSecurity;
501 :
502 : /*
503 : * Each rule action's jointree should be the main parsetree's jointree
504 : * plus that rule's jointree, but usually *without* the original rtindex
505 : * that we're replacing (if present, which it won't be for INSERT). Note
506 : * that if the rule action refers to OLD, its jointree will add a
507 : * reference to rt_index. If the rule action doesn't refer to OLD, but
508 : * either the rule_qual or the user query quals do, then we need to keep
509 : * the original rtindex in the jointree to provide data for the quals. We
510 : * don't want the original rtindex to be joined twice, however, so avoid
511 : * keeping it if the rule action mentions it.
512 : *
513 : * As above, the action's jointree must not share substructure with the
514 : * main parsetree's.
515 : */
516 1344 : if (sub_action->commandType != CMD_UTILITY)
517 : {
518 : bool keeporig;
519 : List *newjointree;
520 :
521 : Assert(sub_action->jointree != NULL);
522 1320 : keeporig = (!rangeTableEntry_used((Node *) sub_action->jointree,
523 3120 : rt_index, 0)) &&
524 1800 : (rangeTableEntry_used(rule_qual, rt_index, 0) ||
525 900 : rangeTableEntry_used(parsetree->jointree->quals, rt_index, 0));
526 1320 : newjointree = adjustJoinTreeList(parsetree, !keeporig, rt_index);
527 1320 : if (newjointree != NIL)
528 : {
529 : /*
530 : * If sub_action is a setop, manipulating its jointree will do no
531 : * good at all, because the jointree is dummy. (Perhaps someday
532 : * we could push the joining and quals down to the member
533 : * statements of the setop?)
534 : */
535 276 : if (sub_action->setOperations != NULL)
536 0 : ereport(ERROR,
537 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
538 : errmsg("conditional UNION/INTERSECT/EXCEPT statements are not implemented")));
539 :
540 552 : sub_action->jointree->fromlist =
541 276 : list_concat(newjointree, sub_action->jointree->fromlist);
542 :
543 : /*
544 : * There could have been some SubLinks in newjointree, in which
545 : * case we'd better mark the sub_action correctly.
546 : */
547 276 : if (parsetree->hasSubLinks && !sub_action->hasSubLinks)
548 6 : sub_action->hasSubLinks =
549 6 : checkExprHasSubLink((Node *) newjointree);
550 : }
551 : }
552 :
553 : /*
554 : * If the original query has any CTEs, copy them into the rule action. But
555 : * we don't need them for a utility action.
556 : */
557 1344 : if (parsetree->cteList != NIL && sub_action->commandType != CMD_UTILITY)
558 : {
559 : /*
560 : * Annoying implementation restriction: because CTEs are identified by
561 : * name within a cteList, we can't merge a CTE from the original query
562 : * if it has the same name as any CTE in the rule action.
563 : *
564 : * This could possibly be fixed by using some sort of internally
565 : * generated ID, instead of names, to link CTE RTEs to their CTEs.
566 : * However, decompiling the results would be quite confusing; note the
567 : * merge of hasRecursive flags below, which could change the apparent
568 : * semantics of such redundantly-named CTEs.
569 : */
570 60 : foreach(lc, parsetree->cteList)
571 : {
572 30 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
573 : ListCell *lc2;
574 :
575 30 : foreach(lc2, sub_action->cteList)
576 : {
577 0 : CommonTableExpr *cte2 = (CommonTableExpr *) lfirst(lc2);
578 :
579 0 : if (strcmp(cte->ctename, cte2->ctename) == 0)
580 0 : ereport(ERROR,
581 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
582 : errmsg("WITH query name \"%s\" appears in both a rule action and the query being rewritten",
583 : cte->ctename)));
584 : }
585 : }
586 :
587 : /* OK, it's safe to combine the CTE lists */
588 30 : sub_action->cteList = list_concat(sub_action->cteList,
589 30 : copyObject(parsetree->cteList));
590 : /* ... and don't forget about the associated flags */
591 30 : sub_action->hasRecursive |= parsetree->hasRecursive;
592 30 : sub_action->hasModifyingCTE |= parsetree->hasModifyingCTE;
593 :
594 : /*
595 : * If rule_action is different from sub_action (i.e., the rule action
596 : * is an INSERT...SELECT), then we might have just added some
597 : * data-modifying CTEs that are not at the top query level. This is
598 : * disallowed by the parser and we mustn't generate such trees here
599 : * either, so throw an error.
600 : *
601 : * Conceivably such cases could be supported by attaching the original
602 : * query's CTEs to rule_action not sub_action. But to do that, we'd
603 : * have to increment ctelevelsup in RTEs and SubLinks copied from the
604 : * original query. For now, it doesn't seem worth the trouble.
605 : */
606 30 : if (sub_action->hasModifyingCTE && rule_action != sub_action)
607 6 : ereport(ERROR,
608 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
609 : errmsg("INSERT ... SELECT rule actions are not supported for queries having data-modifying statements in WITH")));
610 : }
611 :
612 : /*
613 : * Event Qualification forces copying of parsetree and splitting into two
614 : * queries one w/rule_qual, one w/NOT rule_qual. Also add user query qual
615 : * onto rule action
616 : */
617 1338 : AddQual(sub_action, rule_qual);
618 :
619 1338 : AddQual(sub_action, parsetree->jointree->quals);
620 :
621 : /*
622 : * Rewrite new.attribute with right hand side of target-list entry for
623 : * appropriate field name in insert/update.
624 : *
625 : * KLUGE ALERT: since ReplaceVarsFromTargetList returns a mutated copy, we
626 : * can't just apply it to sub_action; we have to remember to update the
627 : * sublink inside rule_action, too.
628 : */
629 1338 : if ((event == CMD_INSERT || event == CMD_UPDATE) &&
630 1170 : sub_action->commandType != CMD_UTILITY)
631 : {
632 : sub_action = (Query *)
633 2292 : ReplaceVarsFromTargetList((Node *) sub_action,
634 : new_varno,
635 : 0,
636 1146 : rt_fetch(new_varno, sub_action->rtable),
637 : parsetree->targetList,
638 : (event == CMD_UPDATE) ?
639 : REPLACEVARS_CHANGE_VARNO :
640 : REPLACEVARS_SUBSTITUTE_NULL,
641 : current_varno,
642 : NULL);
643 1146 : if (sub_action_ptr)
644 54 : *sub_action_ptr = sub_action;
645 : else
646 1092 : rule_action = sub_action;
647 : }
648 :
649 : /*
650 : * If rule_action has a RETURNING clause, then either throw it away if the
651 : * triggering query has no RETURNING clause, or rewrite it to emit what
652 : * the triggering query's RETURNING clause asks for. Throw an error if
653 : * more than one rule has a RETURNING clause.
654 : */
655 1338 : if (!parsetree->returningList)
656 1218 : rule_action->returningList = NIL;
657 120 : else if (rule_action->returningList)
658 : {
659 108 : if (*returning_flag)
660 0 : ereport(ERROR,
661 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
662 : errmsg("cannot have RETURNING lists in multiple rules")));
663 108 : *returning_flag = true;
664 108 : rule_action->returningList = (List *)
665 108 : ReplaceVarsFromTargetList((Node *) parsetree->returningList,
666 : parsetree->resultRelation,
667 : 0,
668 108 : rt_fetch(parsetree->resultRelation,
669 : parsetree->rtable),
670 : rule_action->returningList,
671 : REPLACEVARS_REPORT_ERROR,
672 : 0,
673 : &rule_action->hasSubLinks);
674 :
675 : /*
676 : * There could have been some SubLinks in parsetree's returningList,
677 : * in which case we'd better mark the rule_action correctly.
678 : */
679 108 : if (parsetree->hasSubLinks && !rule_action->hasSubLinks)
680 0 : rule_action->hasSubLinks =
681 0 : checkExprHasSubLink((Node *) rule_action->returningList);
682 : }
683 :
684 1338 : return rule_action;
685 : }
686 :
687 : /*
688 : * Copy the query's jointree list, and optionally attempt to remove any
689 : * occurrence of the given rt_index as a top-level join item (we do not look
690 : * for it within join items; this is OK because we are only expecting to find
691 : * it as an UPDATE or DELETE target relation, which will be at the top level
692 : * of the join). Returns modified jointree list --- this is a separate copy
693 : * sharing no nodes with the original.
694 : */
695 : static List *
696 1320 : adjustJoinTreeList(Query *parsetree, bool removert, int rt_index)
697 : {
698 1320 : List *newjointree = copyObject(parsetree->jointree->fromlist);
699 : ListCell *l;
700 :
701 1320 : if (removert)
702 : {
703 1560 : foreach(l, newjointree)
704 : {
705 714 : RangeTblRef *rtr = lfirst(l);
706 :
707 714 : if (IsA(rtr, RangeTblRef) &&
708 714 : rtr->rtindex == rt_index)
709 : {
710 474 : newjointree = foreach_delete_current(newjointree, l);
711 474 : break;
712 : }
713 : }
714 : }
715 1320 : return newjointree;
716 : }
717 :
718 :
719 : /*
720 : * rewriteTargetListIU - rewrite INSERT/UPDATE targetlist into standard form
721 : *
722 : * This has the following responsibilities:
723 : *
724 : * 1. For an INSERT, add tlist entries to compute default values for any
725 : * attributes that have defaults and are not assigned to in the given tlist.
726 : * (We do not insert anything for default-less attributes, however. The
727 : * planner will later insert NULLs for them, but there's no reason to slow
728 : * down rewriter processing with extra tlist nodes.) Also, for both INSERT
729 : * and UPDATE, replace explicit DEFAULT specifications with column default
730 : * expressions.
731 : *
732 : * 2. Merge multiple entries for the same target attribute, or declare error
733 : * if we can't. Multiple entries are only allowed for INSERT/UPDATE of
734 : * portions of an array or record field, for example
735 : * UPDATE table SET foo[2] = 42, foo[4] = 43;
736 : * We can merge such operations into a single assignment op. Essentially,
737 : * the expression we want to produce in this case is like
738 : * foo = array_set_element(array_set_element(foo, 2, 42), 4, 43)
739 : *
740 : * 3. Sort the tlist into standard order: non-junk fields in order by resno,
741 : * then junk fields (these in no particular order).
742 : *
743 : * We must do items 1 and 2 before firing rewrite rules, else rewritten
744 : * references to NEW.foo will produce wrong or incomplete results. Item 3
745 : * is not needed for rewriting, but it is helpful for the planner, and we
746 : * can do it essentially for free while handling the other items.
747 : *
748 : * If values_rte is non-NULL (i.e., we are doing a multi-row INSERT using
749 : * values from a VALUES RTE), we populate *unused_values_attrnos with the
750 : * attribute numbers of any unused columns from the VALUES RTE. This can
751 : * happen for identity and generated columns whose targetlist entries are
752 : * replaced with generated expressions (if INSERT ... OVERRIDING USER VALUE is
753 : * used, or all the values to be inserted are DEFAULT). This information is
754 : * required by rewriteValuesRTE() to handle any DEFAULT items in the unused
755 : * columns. The caller must have initialized *unused_values_attrnos to NULL.
756 : */
757 : static List *
758 88854 : rewriteTargetListIU(List *targetList,
759 : CmdType commandType,
760 : OverridingKind override,
761 : Relation target_relation,
762 : RangeTblEntry *values_rte,
763 : int values_rte_index,
764 : Bitmapset **unused_values_attrnos)
765 : {
766 : TargetEntry **new_tles;
767 88854 : List *new_tlist = NIL;
768 88854 : List *junk_tlist = NIL;
769 : Form_pg_attribute att_tup;
770 : int attrno,
771 : next_junk_attrno,
772 : numattrs;
773 : ListCell *temp;
774 88854 : Bitmapset *default_only_cols = NULL;
775 :
776 : /*
777 : * We process the normal (non-junk) attributes by scanning the input tlist
778 : * once and transferring TLEs into an array, then scanning the array to
779 : * build an output tlist. This avoids O(N^2) behavior for large numbers
780 : * of attributes.
781 : *
782 : * Junk attributes are tossed into a separate list during the same tlist
783 : * scan, then appended to the reconstructed tlist.
784 : */
785 88854 : numattrs = RelationGetNumberOfAttributes(target_relation);
786 88854 : new_tles = (TargetEntry **) palloc0(numattrs * sizeof(TargetEntry *));
787 88854 : next_junk_attrno = numattrs + 1;
788 :
789 242486 : foreach(temp, targetList)
790 : {
791 153650 : TargetEntry *old_tle = (TargetEntry *) lfirst(temp);
792 :
793 153650 : if (!old_tle->resjunk)
794 : {
795 : /* Normal attr: stash it into new_tles[] */
796 153518 : attrno = old_tle->resno;
797 153518 : if (attrno < 1 || attrno > numattrs)
798 0 : elog(ERROR, "bogus resno %d in targetlist", attrno);
799 153518 : att_tup = TupleDescAttr(target_relation->rd_att, attrno - 1);
800 :
801 : /* We can (and must) ignore deleted attributes */
802 153518 : if (att_tup->attisdropped)
803 0 : continue;
804 :
805 : /* Merge with any prior assignment to same attribute */
806 153500 : new_tles[attrno - 1] =
807 153518 : process_matched_tle(old_tle,
808 153518 : new_tles[attrno - 1],
809 153518 : NameStr(att_tup->attname));
810 : }
811 : else
812 : {
813 : /*
814 : * Copy all resjunk tlist entries to junk_tlist, and assign them
815 : * resnos above the last real resno.
816 : *
817 : * Typical junk entries include ORDER BY or GROUP BY expressions
818 : * (are these actually possible in an INSERT or UPDATE?), system
819 : * attribute references, etc.
820 : */
821 :
822 : /* Get the resno right, but don't copy unnecessarily */
823 132 : if (old_tle->resno != next_junk_attrno)
824 : {
825 0 : old_tle = flatCopyTargetEntry(old_tle);
826 0 : old_tle->resno = next_junk_attrno;
827 : }
828 132 : junk_tlist = lappend(junk_tlist, old_tle);
829 132 : next_junk_attrno++;
830 : }
831 : }
832 :
833 383768 : for (attrno = 1; attrno <= numattrs; attrno++)
834 : {
835 295058 : TargetEntry *new_tle = new_tles[attrno - 1];
836 : bool apply_default;
837 :
838 295058 : att_tup = TupleDescAttr(target_relation->rd_att, attrno - 1);
839 :
840 : /* We can (and must) ignore deleted attributes */
841 295058 : if (att_tup->attisdropped)
842 896 : continue;
843 :
844 : /*
845 : * Handle the two cases where we need to insert a default expression:
846 : * it's an INSERT and there's no tlist entry for the column, or the
847 : * tlist entry is a DEFAULT placeholder node.
848 : */
849 447270 : apply_default = ((new_tle == NULL && commandType == CMD_INSERT) ||
850 153108 : (new_tle && new_tle->expr && IsA(new_tle->expr, SetToDefault)));
851 :
852 294162 : if (commandType == CMD_INSERT)
853 : {
854 156852 : int values_attrno = 0;
855 :
856 : /* Source attribute number for values that come from a VALUES RTE */
857 156852 : if (values_rte && new_tle && IsA(new_tle->expr, Var))
858 : {
859 7798 : Var *var = (Var *) new_tle->expr;
860 :
861 7798 : if (var->varno == values_rte_index)
862 7798 : values_attrno = var->varattno;
863 : }
864 :
865 : /*
866 : * Can only insert DEFAULT into GENERATED ALWAYS identity columns,
867 : * unless either OVERRIDING USER VALUE or OVERRIDING SYSTEM VALUE
868 : * is specified.
869 : */
870 156852 : if (att_tup->attidentity == ATTRIBUTE_IDENTITY_ALWAYS && !apply_default)
871 : {
872 142 : if (override == OVERRIDING_USER_VALUE)
873 42 : apply_default = true;
874 100 : else if (override != OVERRIDING_SYSTEM_VALUE)
875 : {
876 : /*
877 : * If this column's values come from a VALUES RTE, test
878 : * whether it contains only SetToDefault items. Since the
879 : * VALUES list might be quite large, we arrange to only
880 : * scan it once.
881 : */
882 52 : if (values_attrno != 0)
883 : {
884 28 : if (default_only_cols == NULL)
885 28 : default_only_cols = findDefaultOnlyColumns(values_rte);
886 :
887 28 : if (bms_is_member(values_attrno, default_only_cols))
888 10 : apply_default = true;
889 : }
890 :
891 52 : if (!apply_default)
892 42 : ereport(ERROR,
893 : (errcode(ERRCODE_GENERATED_ALWAYS),
894 : errmsg("cannot insert a non-DEFAULT value into column \"%s\"",
895 : NameStr(att_tup->attname)),
896 : errdetail("Column \"%s\" is an identity column defined as GENERATED ALWAYS.",
897 : NameStr(att_tup->attname)),
898 : errhint("Use OVERRIDING SYSTEM VALUE to override.")));
899 : }
900 : }
901 :
902 : /*
903 : * Although inserting into a GENERATED BY DEFAULT identity column
904 : * is allowed, apply the default if OVERRIDING USER VALUE is
905 : * specified.
906 : */
907 156810 : if (att_tup->attidentity == ATTRIBUTE_IDENTITY_BY_DEFAULT &&
908 : override == OVERRIDING_USER_VALUE)
909 18 : apply_default = true;
910 :
911 : /*
912 : * Can only insert DEFAULT into generated columns, regardless of
913 : * any OVERRIDING clauses.
914 : */
915 156810 : if (att_tup->attgenerated && !apply_default)
916 : {
917 : /*
918 : * If this column's values come from a VALUES RTE, test
919 : * whether it contains only SetToDefault items, as above.
920 : */
921 86 : if (values_attrno != 0)
922 : {
923 56 : if (default_only_cols == NULL)
924 56 : default_only_cols = findDefaultOnlyColumns(values_rte);
925 :
926 56 : if (bms_is_member(values_attrno, default_only_cols))
927 14 : apply_default = true;
928 : }
929 :
930 86 : if (!apply_default)
931 72 : ereport(ERROR,
932 : (errcode(ERRCODE_GENERATED_ALWAYS),
933 : errmsg("cannot insert a non-DEFAULT value into column \"%s\"",
934 : NameStr(att_tup->attname)),
935 : errdetail("Column \"%s\" is a generated column.",
936 : NameStr(att_tup->attname))));
937 : }
938 :
939 : /*
940 : * For an INSERT from a VALUES RTE, return the attribute numbers
941 : * of any VALUES columns that will no longer be used (due to the
942 : * targetlist entry being replaced by a default expression).
943 : */
944 156738 : if (values_attrno != 0 && apply_default && unused_values_attrnos)
945 48 : *unused_values_attrnos = bms_add_member(*unused_values_attrnos,
946 : values_attrno);
947 : }
948 :
949 : /*
950 : * Updates to identity and generated columns follow the same rules as
951 : * above, except that UPDATE doesn't admit OVERRIDING clauses. Also,
952 : * the source can't be a VALUES RTE, so we needn't consider that.
953 : */
954 294048 : if (commandType == CMD_UPDATE)
955 : {
956 137310 : if (att_tup->attidentity == ATTRIBUTE_IDENTITY_ALWAYS &&
957 12 : new_tle && !apply_default)
958 6 : ereport(ERROR,
959 : (errcode(ERRCODE_GENERATED_ALWAYS),
960 : errmsg("column \"%s\" can only be updated to DEFAULT",
961 : NameStr(att_tup->attname)),
962 : errdetail("Column \"%s\" is an identity column defined as GENERATED ALWAYS.",
963 : NameStr(att_tup->attname))));
964 :
965 137304 : if (att_tup->attgenerated && new_tle && !apply_default)
966 6 : ereport(ERROR,
967 : (errcode(ERRCODE_GENERATED_ALWAYS),
968 : errmsg("column \"%s\" can only be updated to DEFAULT",
969 : NameStr(att_tup->attname)),
970 : errdetail("Column \"%s\" is a generated column.",
971 : NameStr(att_tup->attname))));
972 : }
973 :
974 294036 : if (att_tup->attgenerated)
975 : {
976 : /*
977 : * stored generated column will be fixed in executor
978 : */
979 928 : new_tle = NULL;
980 : }
981 293108 : else if (apply_default)
982 : {
983 : Node *new_expr;
984 :
985 24928 : new_expr = build_column_default(target_relation, attrno);
986 :
987 : /*
988 : * If there is no default (ie, default is effectively NULL), we
989 : * can omit the tlist entry in the INSERT case, since the planner
990 : * can insert a NULL for itself, and there's no point in spending
991 : * any more rewriter cycles on the entry. But in the UPDATE case
992 : * we've got to explicitly set the column to NULL.
993 : */
994 24928 : if (!new_expr)
995 : {
996 18428 : if (commandType == CMD_INSERT)
997 18410 : new_tle = NULL;
998 : else
999 : {
1000 18 : new_expr = (Node *) makeConst(att_tup->atttypid,
1001 : -1,
1002 : att_tup->attcollation,
1003 18 : att_tup->attlen,
1004 : (Datum) 0,
1005 : true, /* isnull */
1006 18 : att_tup->attbyval);
1007 : /* this is to catch a NOT NULL domain constraint */
1008 18 : new_expr = coerce_to_domain(new_expr,
1009 : InvalidOid, -1,
1010 : att_tup->atttypid,
1011 : COERCION_IMPLICIT,
1012 : COERCE_IMPLICIT_CAST,
1013 : -1,
1014 : false);
1015 : }
1016 : }
1017 :
1018 24928 : if (new_expr)
1019 6518 : new_tle = makeTargetEntry((Expr *) new_expr,
1020 : attrno,
1021 6518 : pstrdup(NameStr(att_tup->attname)),
1022 : false);
1023 : }
1024 :
1025 294036 : if (new_tle)
1026 158776 : new_tlist = lappend(new_tlist, new_tle);
1027 : }
1028 :
1029 88710 : pfree(new_tles);
1030 :
1031 88710 : return list_concat(new_tlist, junk_tlist);
1032 : }
1033 :
1034 :
1035 : /*
1036 : * Convert a matched TLE from the original tlist into a correct new TLE.
1037 : *
1038 : * This routine detects and handles multiple assignments to the same target
1039 : * attribute. (The attribute name is needed only for error messages.)
1040 : */
1041 : static TargetEntry *
1042 153518 : process_matched_tle(TargetEntry *src_tle,
1043 : TargetEntry *prior_tle,
1044 : const char *attrName)
1045 : {
1046 : TargetEntry *result;
1047 153518 : CoerceToDomain *coerce_expr = NULL;
1048 : Node *src_expr;
1049 : Node *prior_expr;
1050 : Node *src_input;
1051 : Node *prior_input;
1052 : Node *priorbottom;
1053 : Node *newexpr;
1054 :
1055 153518 : if (prior_tle == NULL)
1056 : {
1057 : /*
1058 : * Normal case where this is the first assignment to the attribute.
1059 : */
1060 153180 : return src_tle;
1061 : }
1062 :
1063 : /*----------
1064 : * Multiple assignments to same attribute. Allow only if all are
1065 : * FieldStore or SubscriptingRef assignment operations. This is a bit
1066 : * tricky because what we may actually be looking at is a nest of
1067 : * such nodes; consider
1068 : * UPDATE tab SET col.fld1.subfld1 = x, col.fld2.subfld2 = y
1069 : * The two expressions produced by the parser will look like
1070 : * FieldStore(col, fld1, FieldStore(placeholder, subfld1, x))
1071 : * FieldStore(col, fld2, FieldStore(placeholder, subfld2, y))
1072 : * However, we can ignore the substructure and just consider the top
1073 : * FieldStore or SubscriptingRef from each assignment, because it works to
1074 : * combine these as
1075 : * FieldStore(FieldStore(col, fld1,
1076 : * FieldStore(placeholder, subfld1, x)),
1077 : * fld2, FieldStore(placeholder, subfld2, y))
1078 : * Note the leftmost expression goes on the inside so that the
1079 : * assignments appear to occur left-to-right.
1080 : *
1081 : * For FieldStore, instead of nesting we can generate a single
1082 : * FieldStore with multiple target fields. We must nest when
1083 : * SubscriptingRefs are involved though.
1084 : *
1085 : * As a further complication, the destination column might be a domain,
1086 : * resulting in each assignment containing a CoerceToDomain node over a
1087 : * FieldStore or SubscriptingRef. These should have matching target
1088 : * domains, so we strip them and reconstitute a single CoerceToDomain over
1089 : * the combined FieldStore/SubscriptingRef nodes. (Notice that this has
1090 : * the result that the domain's checks are applied only after we do all
1091 : * the field or element updates, not after each one. This is desirable.)
1092 : *----------
1093 : */
1094 338 : src_expr = (Node *) src_tle->expr;
1095 338 : prior_expr = (Node *) prior_tle->expr;
1096 :
1097 338 : if (src_expr && IsA(src_expr, CoerceToDomain) &&
1098 162 : prior_expr && IsA(prior_expr, CoerceToDomain) &&
1099 162 : ((CoerceToDomain *) src_expr)->resulttype ==
1100 162 : ((CoerceToDomain *) prior_expr)->resulttype)
1101 : {
1102 : /* we assume without checking that resulttypmod/resultcollid match */
1103 162 : coerce_expr = (CoerceToDomain *) src_expr;
1104 162 : src_expr = (Node *) ((CoerceToDomain *) src_expr)->arg;
1105 162 : prior_expr = (Node *) ((CoerceToDomain *) prior_expr)->arg;
1106 : }
1107 :
1108 338 : src_input = get_assignment_input(src_expr);
1109 338 : prior_input = get_assignment_input(prior_expr);
1110 338 : if (src_input == NULL ||
1111 320 : prior_input == NULL ||
1112 320 : exprType(src_expr) != exprType(prior_expr))
1113 18 : ereport(ERROR,
1114 : (errcode(ERRCODE_SYNTAX_ERROR),
1115 : errmsg("multiple assignments to same column \"%s\"",
1116 : attrName)));
1117 :
1118 : /*
1119 : * Prior TLE could be a nest of assignments if we do this more than once.
1120 : */
1121 320 : priorbottom = prior_input;
1122 : for (;;)
1123 42 : {
1124 362 : Node *newbottom = get_assignment_input(priorbottom);
1125 :
1126 362 : if (newbottom == NULL)
1127 320 : break; /* found the original Var reference */
1128 42 : priorbottom = newbottom;
1129 : }
1130 320 : if (!equal(priorbottom, src_input))
1131 0 : ereport(ERROR,
1132 : (errcode(ERRCODE_SYNTAX_ERROR),
1133 : errmsg("multiple assignments to same column \"%s\"",
1134 : attrName)));
1135 :
1136 : /*
1137 : * Looks OK to nest 'em.
1138 : */
1139 320 : if (IsA(src_expr, FieldStore))
1140 : {
1141 126 : FieldStore *fstore = makeNode(FieldStore);
1142 :
1143 126 : if (IsA(prior_expr, FieldStore))
1144 : {
1145 : /* combine the two */
1146 126 : memcpy(fstore, prior_expr, sizeof(FieldStore));
1147 126 : fstore->newvals =
1148 126 : list_concat_copy(((FieldStore *) prior_expr)->newvals,
1149 126 : ((FieldStore *) src_expr)->newvals);
1150 126 : fstore->fieldnums =
1151 126 : list_concat_copy(((FieldStore *) prior_expr)->fieldnums,
1152 126 : ((FieldStore *) src_expr)->fieldnums);
1153 : }
1154 : else
1155 : {
1156 : /* general case, just nest 'em */
1157 0 : memcpy(fstore, src_expr, sizeof(FieldStore));
1158 0 : fstore->arg = (Expr *) prior_expr;
1159 : }
1160 126 : newexpr = (Node *) fstore;
1161 : }
1162 194 : else if (IsA(src_expr, SubscriptingRef))
1163 : {
1164 194 : SubscriptingRef *sbsref = makeNode(SubscriptingRef);
1165 :
1166 194 : memcpy(sbsref, src_expr, sizeof(SubscriptingRef));
1167 194 : sbsref->refexpr = (Expr *) prior_expr;
1168 194 : newexpr = (Node *) sbsref;
1169 : }
1170 : else
1171 : {
1172 0 : elog(ERROR, "cannot happen");
1173 : newexpr = NULL;
1174 : }
1175 :
1176 320 : if (coerce_expr)
1177 : {
1178 : /* put back the CoerceToDomain */
1179 162 : CoerceToDomain *newcoerce = makeNode(CoerceToDomain);
1180 :
1181 162 : memcpy(newcoerce, coerce_expr, sizeof(CoerceToDomain));
1182 162 : newcoerce->arg = (Expr *) newexpr;
1183 162 : newexpr = (Node *) newcoerce;
1184 : }
1185 :
1186 320 : result = flatCopyTargetEntry(src_tle);
1187 320 : result->expr = (Expr *) newexpr;
1188 320 : return result;
1189 : }
1190 :
1191 : /*
1192 : * If node is an assignment node, return its input; else return NULL
1193 : */
1194 : static Node *
1195 1038 : get_assignment_input(Node *node)
1196 : {
1197 1038 : if (node == NULL)
1198 0 : return NULL;
1199 1038 : if (IsA(node, FieldStore))
1200 : {
1201 252 : FieldStore *fstore = (FieldStore *) node;
1202 :
1203 252 : return (Node *) fstore->arg;
1204 : }
1205 786 : else if (IsA(node, SubscriptingRef))
1206 : {
1207 430 : SubscriptingRef *sbsref = (SubscriptingRef *) node;
1208 :
1209 430 : if (sbsref->refassgnexpr == NULL)
1210 0 : return NULL;
1211 :
1212 430 : return (Node *) sbsref->refexpr;
1213 : }
1214 :
1215 356 : return NULL;
1216 : }
1217 :
1218 : /*
1219 : * Make an expression tree for the default value for a column.
1220 : *
1221 : * If there is no default, return a NULL instead.
1222 : */
1223 : Node *
1224 185784 : build_column_default(Relation rel, int attrno)
1225 : {
1226 185784 : TupleDesc rd_att = rel->rd_att;
1227 185784 : Form_pg_attribute att_tup = TupleDescAttr(rd_att, attrno - 1);
1228 185784 : Oid atttype = att_tup->atttypid;
1229 185784 : int32 atttypmod = att_tup->atttypmod;
1230 185784 : Node *expr = NULL;
1231 : Oid exprtype;
1232 :
1233 185784 : if (att_tup->attidentity)
1234 : {
1235 450 : NextValueExpr *nve = makeNode(NextValueExpr);
1236 : Oid reloid;
1237 :
1238 : /*
1239 : * The identity sequence is associated with the topmost partitioned
1240 : * table.
1241 : */
1242 450 : if (rel->rd_rel->relispartition)
1243 : {
1244 : List *ancestors =
1245 36 : get_partition_ancestors(RelationGetRelid(rel));
1246 :
1247 36 : reloid = llast_oid(ancestors);
1248 36 : list_free(ancestors);
1249 : }
1250 : else
1251 414 : reloid = RelationGetRelid(rel);
1252 :
1253 450 : nve->seqid = getIdentitySequence(reloid, attrno, false);
1254 450 : nve->typeId = att_tup->atttypid;
1255 :
1256 450 : return (Node *) nve;
1257 : }
1258 :
1259 : /*
1260 : * If relation has a default for this column, fetch that expression.
1261 : */
1262 185334 : if (att_tup->atthasdef)
1263 : {
1264 148396 : expr = TupleDescGetDefault(rd_att, attrno);
1265 148396 : if (expr == NULL)
1266 0 : elog(ERROR, "default expression not found for attribute %d of relation \"%s\"",
1267 : attrno, RelationGetRelationName(rel));
1268 : }
1269 :
1270 : /*
1271 : * No per-column default, so look for a default for the type itself. But
1272 : * not for generated columns.
1273 : */
1274 185334 : if (expr == NULL && !att_tup->attgenerated)
1275 36938 : expr = get_typdefault(atttype);
1276 :
1277 185334 : if (expr == NULL)
1278 36720 : return NULL; /* No default anywhere */
1279 :
1280 : /*
1281 : * Make sure the value is coerced to the target column type; this will
1282 : * generally be true already, but there seem to be some corner cases
1283 : * involving domain defaults where it might not be true. This should match
1284 : * the parser's processing of non-defaulted expressions --- see
1285 : * transformAssignedExpr().
1286 : */
1287 148614 : exprtype = exprType(expr);
1288 :
1289 148614 : expr = coerce_to_target_type(NULL, /* no UNKNOWN params here */
1290 : expr, exprtype,
1291 : atttype, atttypmod,
1292 : COERCION_ASSIGNMENT,
1293 : COERCE_IMPLICIT_CAST,
1294 : -1);
1295 148614 : if (expr == NULL)
1296 0 : ereport(ERROR,
1297 : (errcode(ERRCODE_DATATYPE_MISMATCH),
1298 : errmsg("column \"%s\" is of type %s"
1299 : " but default expression is of type %s",
1300 : NameStr(att_tup->attname),
1301 : format_type_be(atttype),
1302 : format_type_be(exprtype)),
1303 : errhint("You will need to rewrite or cast the expression.")));
1304 :
1305 148614 : return expr;
1306 : }
1307 :
1308 :
1309 : /* Does VALUES RTE contain any SetToDefault items? */
1310 : static bool
1311 4366 : searchForDefault(RangeTblEntry *rte)
1312 : {
1313 : ListCell *lc;
1314 :
1315 18112 : foreach(lc, rte->values_lists)
1316 : {
1317 14010 : List *sublist = (List *) lfirst(lc);
1318 : ListCell *lc2;
1319 :
1320 40738 : foreach(lc2, sublist)
1321 : {
1322 26992 : Node *col = (Node *) lfirst(lc2);
1323 :
1324 26992 : if (IsA(col, SetToDefault))
1325 264 : return true;
1326 : }
1327 : }
1328 4102 : return false;
1329 : }
1330 :
1331 :
1332 : /*
1333 : * Search a VALUES RTE for columns that contain only SetToDefault items,
1334 : * returning a Bitmapset containing the attribute numbers of any such columns.
1335 : */
1336 : static Bitmapset *
1337 84 : findDefaultOnlyColumns(RangeTblEntry *rte)
1338 : {
1339 84 : Bitmapset *default_only_cols = NULL;
1340 : ListCell *lc;
1341 :
1342 150 : foreach(lc, rte->values_lists)
1343 : {
1344 126 : List *sublist = (List *) lfirst(lc);
1345 : ListCell *lc2;
1346 : int i;
1347 :
1348 126 : if (default_only_cols == NULL)
1349 : {
1350 : /* Populate the initial result bitmap from the first row */
1351 84 : i = 0;
1352 250 : foreach(lc2, sublist)
1353 : {
1354 166 : Node *col = (Node *) lfirst(lc2);
1355 :
1356 166 : i++;
1357 166 : if (IsA(col, SetToDefault))
1358 42 : default_only_cols = bms_add_member(default_only_cols, i);
1359 : }
1360 : }
1361 : else
1362 : {
1363 : /* Update the result bitmap from this next row */
1364 42 : i = 0;
1365 124 : foreach(lc2, sublist)
1366 : {
1367 82 : Node *col = (Node *) lfirst(lc2);
1368 :
1369 82 : i++;
1370 82 : if (!IsA(col, SetToDefault))
1371 58 : default_only_cols = bms_del_member(default_only_cols, i);
1372 : }
1373 : }
1374 :
1375 : /*
1376 : * If no column in the rows read so far contains only DEFAULT items,
1377 : * we are done.
1378 : */
1379 126 : if (bms_is_empty(default_only_cols))
1380 60 : break;
1381 : }
1382 :
1383 84 : return default_only_cols;
1384 : }
1385 :
1386 :
1387 : /*
1388 : * When processing INSERT ... VALUES with a VALUES RTE (ie, multiple VALUES
1389 : * lists), we have to replace any DEFAULT items in the VALUES lists with
1390 : * the appropriate default expressions. The other aspects of targetlist
1391 : * rewriting need be applied only to the query's targetlist proper.
1392 : *
1393 : * For an auto-updatable view, each DEFAULT item in the VALUES list is
1394 : * replaced with the default from the view, if it has one. Otherwise it is
1395 : * left untouched so that the underlying base relation's default can be
1396 : * applied instead (when we later recurse to here after rewriting the query
1397 : * to refer to the base relation instead of the view).
1398 : *
1399 : * For other types of relation, including rule- and trigger-updatable views,
1400 : * all DEFAULT items are replaced, and if the target relation doesn't have a
1401 : * default, the value is explicitly set to NULL.
1402 : *
1403 : * Also, if a DEFAULT item is found in a column mentioned in unused_cols,
1404 : * it is explicitly set to NULL. This happens for columns in the VALUES RTE
1405 : * whose corresponding targetlist entries have already been replaced with the
1406 : * relation's default expressions, so that any values in those columns of the
1407 : * VALUES RTE are no longer used. This can happen for identity and generated
1408 : * columns (if INSERT ... OVERRIDING USER VALUE is used, or all the values to
1409 : * be inserted are DEFAULT). In principle we could replace all entries in
1410 : * such a column with NULL, whether DEFAULT or not; but it doesn't seem worth
1411 : * the trouble.
1412 : *
1413 : * Note that we may have subscripted or field assignment targetlist entries,
1414 : * as well as more complex expressions from already-replaced DEFAULT items if
1415 : * we have recursed to here for an auto-updatable view. However, it ought to
1416 : * be impossible for such entries to have DEFAULTs assigned to them, except
1417 : * for unused columns, as described above --- we should only have to replace
1418 : * DEFAULT items for targetlist entries that contain simple Vars referencing
1419 : * the VALUES RTE, or which are no longer referred to by the targetlist.
1420 : *
1421 : * Returns true if all DEFAULT items were replaced, and false if some were
1422 : * left untouched.
1423 : */
1424 : static bool
1425 4366 : rewriteValuesRTE(Query *parsetree, RangeTblEntry *rte, int rti,
1426 : Relation target_relation,
1427 : Bitmapset *unused_cols)
1428 : {
1429 : List *newValues;
1430 : ListCell *lc;
1431 : bool isAutoUpdatableView;
1432 : bool allReplaced;
1433 : int numattrs;
1434 : int *attrnos;
1435 :
1436 : /* Steps below are not sensible for non-INSERT queries */
1437 : Assert(parsetree->commandType == CMD_INSERT);
1438 : Assert(rte->rtekind == RTE_VALUES);
1439 :
1440 : /*
1441 : * Rebuilding all the lists is a pretty expensive proposition in a big
1442 : * VALUES list, and it's a waste of time if there aren't any DEFAULT
1443 : * placeholders. So first scan to see if there are any.
1444 : */
1445 4366 : if (!searchForDefault(rte))
1446 4102 : return true; /* nothing to do */
1447 :
1448 : /*
1449 : * Scan the targetlist for entries referring to the VALUES RTE, and note
1450 : * the target attributes. As noted above, we should only need to do this
1451 : * for targetlist entries containing simple Vars --- nothing else in the
1452 : * VALUES RTE should contain DEFAULT items (except possibly for unused
1453 : * columns), and we complain if such a thing does occur.
1454 : */
1455 264 : numattrs = list_length(linitial(rte->values_lists));
1456 264 : attrnos = (int *) palloc0(numattrs * sizeof(int));
1457 :
1458 1118 : foreach(lc, parsetree->targetList)
1459 : {
1460 854 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
1461 :
1462 854 : if (IsA(tle->expr, Var))
1463 : {
1464 718 : Var *var = (Var *) tle->expr;
1465 :
1466 718 : if (var->varno == rti)
1467 : {
1468 718 : int attrno = var->varattno;
1469 :
1470 : Assert(attrno >= 1 && attrno <= numattrs);
1471 718 : attrnos[attrno - 1] = tle->resno;
1472 : }
1473 : }
1474 : }
1475 :
1476 : /*
1477 : * Check if the target relation is an auto-updatable view, in which case
1478 : * unresolved defaults will be left untouched rather than being set to
1479 : * NULL.
1480 : */
1481 264 : isAutoUpdatableView = false;
1482 264 : if (target_relation->rd_rel->relkind == RELKIND_VIEW &&
1483 90 : !view_has_instead_trigger(target_relation, CMD_INSERT, NIL))
1484 : {
1485 : List *locks;
1486 : bool hasUpdate;
1487 : bool found;
1488 : ListCell *l;
1489 :
1490 : /* Look for an unconditional DO INSTEAD rule */
1491 78 : locks = matchLocks(CMD_INSERT, target_relation,
1492 : parsetree->resultRelation, parsetree, &hasUpdate);
1493 :
1494 78 : found = false;
1495 102 : foreach(l, locks)
1496 : {
1497 36 : RewriteRule *rule_lock = (RewriteRule *) lfirst(l);
1498 :
1499 36 : if (rule_lock->isInstead &&
1500 12 : rule_lock->qual == NULL)
1501 : {
1502 12 : found = true;
1503 12 : break;
1504 : }
1505 : }
1506 :
1507 : /*
1508 : * If we didn't find an unconditional DO INSTEAD rule, assume that the
1509 : * view is auto-updatable. If it isn't, rewriteTargetView() will
1510 : * throw an error.
1511 : */
1512 78 : if (!found)
1513 66 : isAutoUpdatableView = true;
1514 : }
1515 :
1516 264 : newValues = NIL;
1517 264 : allReplaced = true;
1518 804 : foreach(lc, rte->values_lists)
1519 : {
1520 540 : List *sublist = (List *) lfirst(lc);
1521 540 : List *newList = NIL;
1522 : ListCell *lc2;
1523 : int i;
1524 :
1525 : Assert(list_length(sublist) == numattrs);
1526 :
1527 540 : i = 0;
1528 2210 : foreach(lc2, sublist)
1529 : {
1530 1670 : Node *col = (Node *) lfirst(lc2);
1531 1670 : int attrno = attrnos[i++];
1532 :
1533 1670 : if (IsA(col, SetToDefault))
1534 : {
1535 : Form_pg_attribute att_tup;
1536 : Node *new_expr;
1537 :
1538 : /*
1539 : * If this column isn't used, just replace the DEFAULT with
1540 : * NULL (attrno will be 0 in this case because the targetlist
1541 : * entry will have been replaced by the default expression).
1542 : */
1543 792 : if (bms_is_member(i, unused_cols))
1544 : {
1545 72 : SetToDefault *def = (SetToDefault *) col;
1546 :
1547 72 : newList = lappend(newList,
1548 72 : makeNullConst(def->typeId,
1549 : def->typeMod,
1550 : def->collation));
1551 72 : continue;
1552 : }
1553 :
1554 720 : if (attrno == 0)
1555 0 : elog(ERROR, "cannot set value in column %d to DEFAULT", i);
1556 : Assert(attrno > 0 && attrno <= target_relation->rd_att->natts);
1557 720 : att_tup = TupleDescAttr(target_relation->rd_att, attrno - 1);
1558 :
1559 720 : if (!att_tup->attisdropped)
1560 720 : new_expr = build_column_default(target_relation, attrno);
1561 : else
1562 0 : new_expr = NULL; /* force a NULL if dropped */
1563 :
1564 : /*
1565 : * If there is no default (ie, default is effectively NULL),
1566 : * we've got to explicitly set the column to NULL, unless the
1567 : * target relation is an auto-updatable view.
1568 : */
1569 720 : if (!new_expr)
1570 : {
1571 330 : if (isAutoUpdatableView)
1572 : {
1573 : /* Leave the value untouched */
1574 126 : newList = lappend(newList, col);
1575 126 : allReplaced = false;
1576 126 : continue;
1577 : }
1578 :
1579 204 : new_expr = (Node *) makeConst(att_tup->atttypid,
1580 : -1,
1581 : att_tup->attcollation,
1582 204 : att_tup->attlen,
1583 : (Datum) 0,
1584 : true, /* isnull */
1585 204 : att_tup->attbyval);
1586 : /* this is to catch a NOT NULL domain constraint */
1587 204 : new_expr = coerce_to_domain(new_expr,
1588 : InvalidOid, -1,
1589 : att_tup->atttypid,
1590 : COERCION_IMPLICIT,
1591 : COERCE_IMPLICIT_CAST,
1592 : -1,
1593 : false);
1594 : }
1595 594 : newList = lappend(newList, new_expr);
1596 : }
1597 : else
1598 878 : newList = lappend(newList, col);
1599 : }
1600 540 : newValues = lappend(newValues, newList);
1601 : }
1602 264 : rte->values_lists = newValues;
1603 :
1604 264 : pfree(attrnos);
1605 :
1606 264 : return allReplaced;
1607 : }
1608 :
1609 : /*
1610 : * Mop up any remaining DEFAULT items in the given VALUES RTE by
1611 : * replacing them with NULL constants.
1612 : *
1613 : * This is used for the product queries generated by DO ALSO rules attached to
1614 : * an auto-updatable view. The action can't depend on the "target relation"
1615 : * since the product query might not have one (it needn't be an INSERT).
1616 : * Essentially, such queries are treated as being attached to a rule-updatable
1617 : * view.
1618 : */
1619 : static void
1620 24 : rewriteValuesRTEToNulls(Query *parsetree, RangeTblEntry *rte)
1621 : {
1622 : List *newValues;
1623 : ListCell *lc;
1624 :
1625 24 : newValues = NIL;
1626 72 : foreach(lc, rte->values_lists)
1627 : {
1628 48 : List *sublist = (List *) lfirst(lc);
1629 48 : List *newList = NIL;
1630 : ListCell *lc2;
1631 :
1632 204 : foreach(lc2, sublist)
1633 : {
1634 156 : Node *col = (Node *) lfirst(lc2);
1635 :
1636 156 : if (IsA(col, SetToDefault))
1637 : {
1638 66 : SetToDefault *def = (SetToDefault *) col;
1639 :
1640 66 : newList = lappend(newList, makeNullConst(def->typeId,
1641 : def->typeMod,
1642 : def->collation));
1643 : }
1644 : else
1645 90 : newList = lappend(newList, col);
1646 : }
1647 48 : newValues = lappend(newValues, newList);
1648 : }
1649 24 : rte->values_lists = newValues;
1650 24 : }
1651 :
1652 :
1653 : /*
1654 : * matchLocks -
1655 : * match a relation's list of locks and returns the matching rules
1656 : */
1657 : static List *
1658 91676 : matchLocks(CmdType event,
1659 : Relation relation,
1660 : int varno,
1661 : Query *parsetree,
1662 : bool *hasUpdate)
1663 : {
1664 91676 : RuleLock *rulelocks = relation->rd_rules;
1665 91676 : List *matching_locks = NIL;
1666 : int nlocks;
1667 : int i;
1668 :
1669 91676 : if (rulelocks == NULL)
1670 86298 : return NIL;
1671 :
1672 5378 : if (parsetree->commandType != CMD_SELECT)
1673 : {
1674 5378 : if (parsetree->resultRelation != varno)
1675 0 : return NIL;
1676 : }
1677 :
1678 5378 : nlocks = rulelocks->numLocks;
1679 :
1680 12346 : for (i = 0; i < nlocks; i++)
1681 : {
1682 6986 : RewriteRule *oneLock = rulelocks->rules[i];
1683 :
1684 6986 : if (oneLock->event == CMD_UPDATE)
1685 642 : *hasUpdate = true;
1686 :
1687 : /*
1688 : * Suppress ON INSERT/UPDATE/DELETE rules that are disabled or
1689 : * configured to not fire during the current session's replication
1690 : * role. ON SELECT rules will always be applied in order to keep views
1691 : * working even in LOCAL or REPLICA role.
1692 : */
1693 6986 : if (oneLock->event != CMD_SELECT)
1694 : {
1695 2652 : if (SessionReplicationRole == SESSION_REPLICATION_ROLE_REPLICA)
1696 : {
1697 12 : if (oneLock->enabled == RULE_FIRES_ON_ORIGIN ||
1698 6 : oneLock->enabled == RULE_DISABLED)
1699 6 : continue;
1700 : }
1701 : else /* ORIGIN or LOCAL ROLE */
1702 : {
1703 2640 : if (oneLock->enabled == RULE_FIRES_ON_REPLICA ||
1704 2634 : oneLock->enabled == RULE_DISABLED)
1705 30 : continue;
1706 : }
1707 :
1708 : /* Non-SELECT rules are not supported for MERGE */
1709 2616 : if (parsetree->commandType == CMD_MERGE)
1710 18 : ereport(ERROR,
1711 : errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1712 : errmsg("cannot execute MERGE on relation \"%s\"",
1713 : RelationGetRelationName(relation)),
1714 : errdetail("MERGE is not supported for relations with rules."));
1715 : }
1716 :
1717 6932 : if (oneLock->event == event)
1718 : {
1719 1536 : if (parsetree->commandType != CMD_SELECT ||
1720 0 : rangeTableEntry_used((Node *) parsetree, varno, 0))
1721 1536 : matching_locks = lappend(matching_locks, oneLock);
1722 : }
1723 : }
1724 :
1725 5360 : return matching_locks;
1726 : }
1727 :
1728 :
1729 : /*
1730 : * ApplyRetrieveRule - expand an ON SELECT rule
1731 : */
1732 : static Query *
1733 12428 : ApplyRetrieveRule(Query *parsetree,
1734 : RewriteRule *rule,
1735 : int rt_index,
1736 : Relation relation,
1737 : List *activeRIRs)
1738 : {
1739 : Query *rule_action;
1740 : RangeTblEntry *rte;
1741 : RowMarkClause *rc;
1742 : int numCols;
1743 :
1744 12428 : if (list_length(rule->actions) != 1)
1745 0 : elog(ERROR, "expected just one rule action");
1746 12428 : if (rule->qual != NULL)
1747 0 : elog(ERROR, "cannot handle qualified ON SELECT rule");
1748 :
1749 12428 : if (rt_index == parsetree->resultRelation)
1750 : {
1751 : /*
1752 : * We have a view as the result relation of the query, and it wasn't
1753 : * rewritten by any rule. This case is supported if there is an
1754 : * INSTEAD OF trigger that will trap attempts to insert/update/delete
1755 : * view rows. The executor will check that; for the moment just plow
1756 : * ahead. We have two cases:
1757 : *
1758 : * For INSERT, we needn't do anything. The unmodified RTE will serve
1759 : * fine as the result relation.
1760 : *
1761 : * For UPDATE/DELETE/MERGE, we need to expand the view so as to have
1762 : * source data for the operation. But we also need an unmodified RTE
1763 : * to serve as the target. So, copy the RTE and add the copy to the
1764 : * rangetable. Note that the copy does not get added to the jointree.
1765 : * Also note that there's a hack in fireRIRrules to avoid calling this
1766 : * function again when it arrives at the copied RTE.
1767 : */
1768 372 : if (parsetree->commandType == CMD_INSERT)
1769 120 : return parsetree;
1770 252 : else if (parsetree->commandType == CMD_UPDATE ||
1771 114 : parsetree->commandType == CMD_DELETE ||
1772 60 : parsetree->commandType == CMD_MERGE)
1773 252 : {
1774 : RangeTblEntry *newrte;
1775 : Var *var;
1776 : TargetEntry *tle;
1777 :
1778 252 : rte = rt_fetch(rt_index, parsetree->rtable);
1779 252 : newrte = copyObject(rte);
1780 252 : parsetree->rtable = lappend(parsetree->rtable, newrte);
1781 252 : parsetree->resultRelation = list_length(parsetree->rtable);
1782 : /* parsetree->mergeTargetRelation unchanged (use expanded view) */
1783 :
1784 : /*
1785 : * For the most part, Vars referencing the view should remain as
1786 : * they are, meaning that they implicitly represent OLD values.
1787 : * But in the RETURNING list if any, we want such Vars to
1788 : * represent NEW values, so change them to reference the new RTE.
1789 : *
1790 : * Since ChangeVarNodes scribbles on the tree in-place, copy the
1791 : * RETURNING list first for safety.
1792 : */
1793 252 : parsetree->returningList = copyObject(parsetree->returningList);
1794 252 : ChangeVarNodes((Node *) parsetree->returningList, rt_index,
1795 : parsetree->resultRelation, 0);
1796 :
1797 : /*
1798 : * To allow the executor to compute the original view row to pass
1799 : * to the INSTEAD OF trigger, we add a resjunk whole-row Var
1800 : * referencing the original RTE. This will later get expanded
1801 : * into a RowExpr computing all the OLD values of the view row.
1802 : */
1803 252 : var = makeWholeRowVar(rte, rt_index, 0, false);
1804 252 : tle = makeTargetEntry((Expr *) var,
1805 252 : list_length(parsetree->targetList) + 1,
1806 : pstrdup("wholerow"),
1807 : true);
1808 :
1809 252 : parsetree->targetList = lappend(parsetree->targetList, tle);
1810 :
1811 : /* Now, continue with expanding the original view RTE */
1812 : }
1813 : else
1814 0 : elog(ERROR, "unrecognized commandType: %d",
1815 : (int) parsetree->commandType);
1816 : }
1817 :
1818 : /*
1819 : * Check if there's a FOR [KEY] UPDATE/SHARE clause applying to this view.
1820 : *
1821 : * Note: we needn't explicitly consider any such clauses appearing in
1822 : * ancestor query levels; their effects have already been pushed down to
1823 : * here by markQueryForLocking, and will be reflected in "rc".
1824 : */
1825 12308 : rc = get_parse_rowmark(parsetree, rt_index);
1826 :
1827 : /*
1828 : * Make a modifiable copy of the view query, and acquire needed locks on
1829 : * the relations it mentions. Force at least RowShareLock for all such
1830 : * rels if there's a FOR [KEY] UPDATE/SHARE clause affecting this view.
1831 : */
1832 12308 : rule_action = copyObject(linitial(rule->actions));
1833 :
1834 12308 : AcquireRewriteLocks(rule_action, true, (rc != NULL));
1835 :
1836 : /*
1837 : * If FOR [KEY] UPDATE/SHARE of view, mark all the contained tables as
1838 : * implicit FOR [KEY] UPDATE/SHARE, the same as the parser would have done
1839 : * if the view's subquery had been written out explicitly.
1840 : */
1841 12308 : if (rc != NULL)
1842 96 : markQueryForLocking(rule_action, (Node *) rule_action->jointree,
1843 : rc->strength, rc->waitPolicy, true);
1844 :
1845 : /*
1846 : * Recursively expand any view references inside the view.
1847 : */
1848 12308 : rule_action = fireRIRrules(rule_action, activeRIRs);
1849 :
1850 : /*
1851 : * Now, plug the view query in as a subselect, converting the relation's
1852 : * original RTE to a subquery RTE.
1853 : */
1854 12278 : rte = rt_fetch(rt_index, parsetree->rtable);
1855 :
1856 12278 : rte->rtekind = RTE_SUBQUERY;
1857 12278 : rte->subquery = rule_action;
1858 12278 : rte->security_barrier = RelationIsSecurityView(relation);
1859 :
1860 : /*
1861 : * Clear fields that should not be set in a subquery RTE. Note that we
1862 : * leave the relid, relkind, rellockmode, and perminfoindex fields set, so
1863 : * that the view relation can be appropriately locked before execution and
1864 : * its permissions checked.
1865 : */
1866 12278 : rte->tablesample = NULL;
1867 12278 : rte->inh = false; /* must not be set for a subquery */
1868 :
1869 : /*
1870 : * Since we allow CREATE OR REPLACE VIEW to add columns to a view, the
1871 : * rule_action might emit more columns than we expected when the current
1872 : * query was parsed. Various places expect rte->eref->colnames to be
1873 : * consistent with the non-junk output columns of the subquery, so patch
1874 : * things up if necessary by adding some dummy column names.
1875 : */
1876 12278 : numCols = ExecCleanTargetListLength(rule_action->targetList);
1877 12296 : while (list_length(rte->eref->colnames) < numCols)
1878 : {
1879 18 : rte->eref->colnames = lappend(rte->eref->colnames,
1880 18 : makeString(pstrdup("?column?")));
1881 : }
1882 :
1883 12278 : return parsetree;
1884 : }
1885 :
1886 : /*
1887 : * Recursively mark all relations used by a view as FOR [KEY] UPDATE/SHARE.
1888 : *
1889 : * This may generate an invalid query, eg if some sub-query uses an
1890 : * aggregate. We leave it to the planner to detect that.
1891 : *
1892 : * NB: this must agree with the parser's transformLockingClause() routine.
1893 : * However, we used to have to avoid marking a view's OLD and NEW rels for
1894 : * updating, which motivated scanning the jointree to determine which rels
1895 : * are used. Possibly that could now be simplified into just scanning the
1896 : * rangetable as the parser does.
1897 : */
1898 : static void
1899 192 : markQueryForLocking(Query *qry, Node *jtnode,
1900 : LockClauseStrength strength, LockWaitPolicy waitPolicy,
1901 : bool pushedDown)
1902 : {
1903 192 : if (jtnode == NULL)
1904 0 : return;
1905 192 : if (IsA(jtnode, RangeTblRef))
1906 : {
1907 96 : int rti = ((RangeTblRef *) jtnode)->rtindex;
1908 96 : RangeTblEntry *rte = rt_fetch(rti, qry->rtable);
1909 :
1910 96 : if (rte->rtekind == RTE_RELATION)
1911 : {
1912 : RTEPermissionInfo *perminfo;
1913 :
1914 96 : applyLockingClause(qry, rti, strength, waitPolicy, pushedDown);
1915 :
1916 96 : perminfo = getRTEPermissionInfo(qry->rteperminfos, rte);
1917 96 : perminfo->requiredPerms |= ACL_SELECT_FOR_UPDATE;
1918 : }
1919 0 : else if (rte->rtekind == RTE_SUBQUERY)
1920 : {
1921 0 : applyLockingClause(qry, rti, strength, waitPolicy, pushedDown);
1922 : /* FOR UPDATE/SHARE of subquery is propagated to subquery's rels */
1923 0 : markQueryForLocking(rte->subquery, (Node *) rte->subquery->jointree,
1924 : strength, waitPolicy, true);
1925 : }
1926 : /* other RTE types are unaffected by FOR UPDATE */
1927 : }
1928 96 : else if (IsA(jtnode, FromExpr))
1929 : {
1930 96 : FromExpr *f = (FromExpr *) jtnode;
1931 : ListCell *l;
1932 :
1933 192 : foreach(l, f->fromlist)
1934 96 : markQueryForLocking(qry, lfirst(l), strength, waitPolicy, pushedDown);
1935 : }
1936 0 : else if (IsA(jtnode, JoinExpr))
1937 : {
1938 0 : JoinExpr *j = (JoinExpr *) jtnode;
1939 :
1940 0 : markQueryForLocking(qry, j->larg, strength, waitPolicy, pushedDown);
1941 0 : markQueryForLocking(qry, j->rarg, strength, waitPolicy, pushedDown);
1942 : }
1943 : else
1944 0 : elog(ERROR, "unrecognized node type: %d",
1945 : (int) nodeTag(jtnode));
1946 : }
1947 :
1948 :
1949 : /*
1950 : * fireRIRonSubLink -
1951 : * Apply fireRIRrules() to each SubLink (subselect in expression) found
1952 : * in the given tree.
1953 : *
1954 : * NOTE: although this has the form of a walker, we cheat and modify the
1955 : * SubLink nodes in-place. It is caller's responsibility to ensure that
1956 : * no unwanted side-effects occur!
1957 : *
1958 : * This is unlike most of the other routines that recurse into subselects,
1959 : * because we must take control at the SubLink node in order to replace
1960 : * the SubLink's subselect link with the possibly-rewritten subquery.
1961 : */
1962 : static bool
1963 2104452 : fireRIRonSubLink(Node *node, List *activeRIRs)
1964 : {
1965 2104452 : if (node == NULL)
1966 396326 : return false;
1967 1708126 : if (IsA(node, SubLink))
1968 : {
1969 37010 : SubLink *sub = (SubLink *) node;
1970 :
1971 : /* Do what we came for */
1972 37010 : sub->subselect = (Node *) fireRIRrules((Query *) sub->subselect,
1973 : activeRIRs);
1974 : /* Fall through to process lefthand args of SubLink */
1975 : }
1976 :
1977 : /*
1978 : * Do NOT recurse into Query nodes, because fireRIRrules already processed
1979 : * subselects of subselects for us.
1980 : */
1981 1708054 : return expression_tree_walker(node, fireRIRonSubLink,
1982 : (void *) activeRIRs);
1983 : }
1984 :
1985 :
1986 : /*
1987 : * fireRIRrules -
1988 : * Apply all RIR rules on each rangetable entry in the given query
1989 : *
1990 : * activeRIRs is a list of the OIDs of views we're already processing RIR
1991 : * rules for, used to detect/reject recursion.
1992 : */
1993 : static Query *
1994 518702 : fireRIRrules(Query *parsetree, List *activeRIRs)
1995 : {
1996 518702 : int origResultRelation = parsetree->resultRelation;
1997 : int rt_index;
1998 : ListCell *lc;
1999 :
2000 : /*
2001 : * Expand SEARCH and CYCLE clauses in CTEs.
2002 : *
2003 : * This is just a convenient place to do this, since we are already
2004 : * looking at each Query.
2005 : */
2006 522116 : foreach(lc, parsetree->cteList)
2007 : {
2008 3420 : CommonTableExpr *cte = lfirst_node(CommonTableExpr, lc);
2009 :
2010 3420 : if (cte->search_clause || cte->cycle_clause)
2011 : {
2012 144 : cte = rewriteSearchAndCycle(cte);
2013 138 : lfirst(lc) = cte;
2014 : }
2015 : }
2016 :
2017 : /*
2018 : * don't try to convert this into a foreach loop, because rtable list can
2019 : * get changed each time through...
2020 : */
2021 518696 : rt_index = 0;
2022 1101344 : while (rt_index < list_length(parsetree->rtable))
2023 : {
2024 : RangeTblEntry *rte;
2025 : Relation rel;
2026 : List *locks;
2027 : RuleLock *rules;
2028 : RewriteRule *rule;
2029 : int i;
2030 :
2031 582678 : ++rt_index;
2032 :
2033 582678 : rte = rt_fetch(rt_index, parsetree->rtable);
2034 :
2035 : /*
2036 : * A subquery RTE can't have associated rules, so there's nothing to
2037 : * do to this level of the query, but we must recurse into the
2038 : * subquery to expand any rule references in it.
2039 : */
2040 582678 : if (rte->rtekind == RTE_SUBQUERY)
2041 : {
2042 36118 : rte->subquery = fireRIRrules(rte->subquery, activeRIRs);
2043 36118 : continue;
2044 : }
2045 :
2046 : /*
2047 : * Joins and other non-relation RTEs can be ignored completely.
2048 : */
2049 546560 : if (rte->rtekind != RTE_RELATION)
2050 128804 : continue;
2051 :
2052 : /*
2053 : * Always ignore RIR rules for materialized views referenced in
2054 : * queries. (This does not prevent refreshing MVs, since they aren't
2055 : * referenced in their own query definitions.)
2056 : *
2057 : * Note: in the future we might want to allow MVs to be conditionally
2058 : * expanded as if they were regular views, if they are not scannable.
2059 : * In that case this test would need to be postponed till after we've
2060 : * opened the rel, so that we could check its state.
2061 : */
2062 417756 : if (rte->relkind == RELKIND_MATVIEW)
2063 458 : continue;
2064 :
2065 : /*
2066 : * In INSERT ... ON CONFLICT, ignore the EXCLUDED pseudo-relation;
2067 : * even if it points to a view, we needn't expand it, and should not
2068 : * because we want the RTE to remain of RTE_RELATION type. Otherwise,
2069 : * it would get changed to RTE_SUBQUERY type, which is an
2070 : * untested/unsupported situation.
2071 : */
2072 417298 : if (parsetree->onConflict &&
2073 2988 : rt_index == parsetree->onConflict->exclRelIndex)
2074 1114 : continue;
2075 :
2076 : /*
2077 : * If the table is not referenced in the query, then we ignore it.
2078 : * This prevents infinite expansion loop due to new rtable entries
2079 : * inserted by expansion of a rule. A table is referenced if it is
2080 : * part of the join set (a source table), or is referenced by any Var
2081 : * nodes, or is the result table.
2082 : */
2083 416184 : if (rt_index != parsetree->resultRelation &&
2084 328506 : !rangeTableEntry_used((Node *) parsetree, rt_index, 0))
2085 7004 : continue;
2086 :
2087 : /*
2088 : * Also, if this is a new result relation introduced by
2089 : * ApplyRetrieveRule, we don't want to do anything more with it.
2090 : */
2091 409180 : if (rt_index == parsetree->resultRelation &&
2092 : rt_index != origResultRelation)
2093 252 : continue;
2094 :
2095 : /*
2096 : * We can use NoLock here since either the parser or
2097 : * AcquireRewriteLocks should have locked the rel already.
2098 : */
2099 408928 : rel = table_open(rte->relid, NoLock);
2100 :
2101 : /*
2102 : * Collect the RIR rules that we must apply
2103 : */
2104 408928 : rules = rel->rd_rules;
2105 408928 : if (rules != NULL)
2106 : {
2107 13652 : locks = NIL;
2108 29398 : for (i = 0; i < rules->numLocks; i++)
2109 : {
2110 15746 : rule = rules->rules[i];
2111 15746 : if (rule->event != CMD_SELECT)
2112 3318 : continue;
2113 :
2114 12428 : locks = lappend(locks, rule);
2115 : }
2116 :
2117 : /*
2118 : * If we found any, apply them --- but first check for recursion!
2119 : */
2120 13652 : if (locks != NIL)
2121 : {
2122 : ListCell *l;
2123 :
2124 12428 : if (list_member_oid(activeRIRs, RelationGetRelid(rel)))
2125 0 : ereport(ERROR,
2126 : (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
2127 : errmsg("infinite recursion detected in rules for relation \"%s\"",
2128 : RelationGetRelationName(rel))));
2129 12428 : activeRIRs = lappend_oid(activeRIRs, RelationGetRelid(rel));
2130 :
2131 24826 : foreach(l, locks)
2132 : {
2133 12428 : rule = lfirst(l);
2134 :
2135 12428 : parsetree = ApplyRetrieveRule(parsetree,
2136 : rule,
2137 : rt_index,
2138 : rel,
2139 : activeRIRs);
2140 : }
2141 :
2142 12398 : activeRIRs = list_delete_last(activeRIRs);
2143 : }
2144 : }
2145 :
2146 408898 : table_close(rel, NoLock);
2147 : }
2148 :
2149 : /* Recurse into subqueries in WITH */
2150 522080 : foreach(lc, parsetree->cteList)
2151 : {
2152 3414 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
2153 :
2154 3414 : cte->ctequery = (Node *)
2155 3414 : fireRIRrules((Query *) cte->ctequery, activeRIRs);
2156 : }
2157 :
2158 : /*
2159 : * Recurse into sublink subqueries, too. But we already did the ones in
2160 : * the rtable and cteList.
2161 : */
2162 518666 : if (parsetree->hasSubLinks)
2163 29094 : query_tree_walker(parsetree, fireRIRonSubLink, (void *) activeRIRs,
2164 : QTW_IGNORE_RC_SUBQUERIES);
2165 :
2166 : /*
2167 : * Apply any row-level security policies. We do this last because it
2168 : * requires special recursion detection if the new quals have sublink
2169 : * subqueries, and if we did it in the loop above query_tree_walker would
2170 : * then recurse into those quals a second time.
2171 : */
2172 518666 : rt_index = 0;
2173 1101152 : foreach(lc, parsetree->rtable)
2174 : {
2175 582648 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
2176 : Relation rel;
2177 : List *securityQuals;
2178 : List *withCheckOptions;
2179 : bool hasRowSecurity;
2180 : bool hasSubLinks;
2181 :
2182 582648 : ++rt_index;
2183 :
2184 : /* Only normal relations can have RLS policies */
2185 582648 : if (rte->rtekind != RTE_RELATION ||
2186 405448 : (rte->relkind != RELKIND_RELATION &&
2187 25350 : rte->relkind != RELKIND_PARTITIONED_TABLE))
2188 186194 : continue;
2189 :
2190 396454 : rel = table_open(rte->relid, NoLock);
2191 :
2192 : /*
2193 : * Fetch any new security quals that must be applied to this RTE.
2194 : */
2195 396454 : get_row_security_policies(parsetree, rte, rt_index,
2196 : &securityQuals, &withCheckOptions,
2197 : &hasRowSecurity, &hasSubLinks);
2198 :
2199 396406 : if (securityQuals != NIL || withCheckOptions != NIL)
2200 : {
2201 2592 : if (hasSubLinks)
2202 : {
2203 : acquireLocksOnSubLinks_context context;
2204 :
2205 : /*
2206 : * Recursively process the new quals, checking for infinite
2207 : * recursion.
2208 : */
2209 660 : if (list_member_oid(activeRIRs, RelationGetRelid(rel)))
2210 42 : ereport(ERROR,
2211 : (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
2212 : errmsg("infinite recursion detected in policy for relation \"%s\"",
2213 : RelationGetRelationName(rel))));
2214 :
2215 618 : activeRIRs = lappend_oid(activeRIRs, RelationGetRelid(rel));
2216 :
2217 : /*
2218 : * get_row_security_policies just passed back securityQuals
2219 : * and/or withCheckOptions, and there were SubLinks, make sure
2220 : * we lock any relations which are referenced.
2221 : *
2222 : * These locks would normally be acquired by the parser, but
2223 : * securityQuals and withCheckOptions are added post-parsing.
2224 : */
2225 618 : context.for_execute = true;
2226 618 : (void) acquireLocksOnSubLinks((Node *) securityQuals, &context);
2227 618 : (void) acquireLocksOnSubLinks((Node *) withCheckOptions,
2228 : &context);
2229 :
2230 : /*
2231 : * Now that we have the locks on anything added by
2232 : * get_row_security_policies, fire any RIR rules for them.
2233 : */
2234 618 : expression_tree_walker((Node *) securityQuals,
2235 : fireRIRonSubLink, (void *) activeRIRs);
2236 :
2237 552 : expression_tree_walker((Node *) withCheckOptions,
2238 : fireRIRonSubLink, (void *) activeRIRs);
2239 :
2240 546 : activeRIRs = list_delete_last(activeRIRs);
2241 : }
2242 :
2243 : /*
2244 : * Add the new security barrier quals to the start of the RTE's
2245 : * list so that they get applied before any existing barrier quals
2246 : * (which would have come from a security-barrier view, and should
2247 : * get lower priority than RLS conditions on the table itself).
2248 : */
2249 4956 : rte->securityQuals = list_concat(securityQuals,
2250 2478 : rte->securityQuals);
2251 :
2252 2478 : parsetree->withCheckOptions = list_concat(withCheckOptions,
2253 2478 : parsetree->withCheckOptions);
2254 : }
2255 :
2256 : /*
2257 : * Make sure the query is marked correctly if row-level security
2258 : * applies, or if the new quals had sublinks.
2259 : */
2260 396292 : if (hasRowSecurity)
2261 3024 : parsetree->hasRowSecurity = true;
2262 396292 : if (hasSubLinks)
2263 546 : parsetree->hasSubLinks = true;
2264 :
2265 396292 : table_close(rel, NoLock);
2266 : }
2267 :
2268 518504 : return parsetree;
2269 : }
2270 :
2271 :
2272 : /*
2273 : * Modify the given query by adding 'AND rule_qual IS NOT TRUE' to its
2274 : * qualification. This is used to generate suitable "else clauses" for
2275 : * conditional INSTEAD rules. (Unfortunately we must use "x IS NOT TRUE",
2276 : * not just "NOT x" which the planner is much smarter about, else we will
2277 : * do the wrong thing when the qual evaluates to NULL.)
2278 : *
2279 : * The rule_qual may contain references to OLD or NEW. OLD references are
2280 : * replaced by references to the specified rt_index (the relation that the
2281 : * rule applies to). NEW references are only possible for INSERT and UPDATE
2282 : * queries on the relation itself, and so they should be replaced by copies
2283 : * of the related entries in the query's own targetlist.
2284 : */
2285 : static Query *
2286 444 : CopyAndAddInvertedQual(Query *parsetree,
2287 : Node *rule_qual,
2288 : int rt_index,
2289 : CmdType event)
2290 : {
2291 : /* Don't scribble on the passed qual (it's in the relcache!) */
2292 444 : Node *new_qual = copyObject(rule_qual);
2293 : acquireLocksOnSubLinks_context context;
2294 :
2295 444 : context.for_execute = true;
2296 :
2297 : /*
2298 : * In case there are subqueries in the qual, acquire necessary locks and
2299 : * fix any deleted JOIN RTE entries. (This is somewhat redundant with
2300 : * rewriteRuleAction, but not entirely ... consider restructuring so that
2301 : * we only need to process the qual this way once.)
2302 : */
2303 444 : (void) acquireLocksOnSubLinks(new_qual, &context);
2304 :
2305 : /* Fix references to OLD */
2306 444 : ChangeVarNodes(new_qual, PRS2_OLD_VARNO, rt_index, 0);
2307 : /* Fix references to NEW */
2308 444 : if (event == CMD_INSERT || event == CMD_UPDATE)
2309 864 : new_qual = ReplaceVarsFromTargetList(new_qual,
2310 : PRS2_NEW_VARNO,
2311 : 0,
2312 432 : rt_fetch(rt_index,
2313 : parsetree->rtable),
2314 : parsetree->targetList,
2315 : (event == CMD_UPDATE) ?
2316 : REPLACEVARS_CHANGE_VARNO :
2317 : REPLACEVARS_SUBSTITUTE_NULL,
2318 : rt_index,
2319 : &parsetree->hasSubLinks);
2320 : /* And attach the fixed qual */
2321 444 : AddInvertedQual(parsetree, new_qual);
2322 :
2323 444 : return parsetree;
2324 : }
2325 :
2326 :
2327 : /*
2328 : * fireRules -
2329 : * Iterate through rule locks applying rules.
2330 : *
2331 : * Input arguments:
2332 : * parsetree - original query
2333 : * rt_index - RT index of result relation in original query
2334 : * event - type of rule event
2335 : * locks - list of rules to fire
2336 : * Output arguments:
2337 : * *instead_flag - set true if any unqualified INSTEAD rule is found
2338 : * (must be initialized to false)
2339 : * *returning_flag - set true if we rewrite RETURNING clause in any rule
2340 : * (must be initialized to false)
2341 : * *qual_product - filled with modified original query if any qualified
2342 : * INSTEAD rule is found (must be initialized to NULL)
2343 : * Return value:
2344 : * list of rule actions adjusted for use with this query
2345 : *
2346 : * Qualified INSTEAD rules generate their action with the qualification
2347 : * condition added. They also generate a modified version of the original
2348 : * query with the negated qualification added, so that it will run only for
2349 : * rows that the qualified action doesn't act on. (If there are multiple
2350 : * qualified INSTEAD rules, we AND all the negated quals onto a single
2351 : * modified original query.) We won't execute the original, unmodified
2352 : * query if we find either qualified or unqualified INSTEAD rules. If
2353 : * we find both, the modified original query is discarded too.
2354 : */
2355 : static List *
2356 91580 : fireRules(Query *parsetree,
2357 : int rt_index,
2358 : CmdType event,
2359 : List *locks,
2360 : bool *instead_flag,
2361 : bool *returning_flag,
2362 : Query **qual_product)
2363 : {
2364 91580 : List *results = NIL;
2365 : ListCell *l;
2366 :
2367 93074 : foreach(l, locks)
2368 : {
2369 1500 : RewriteRule *rule_lock = (RewriteRule *) lfirst(l);
2370 1500 : Node *event_qual = rule_lock->qual;
2371 1500 : List *actions = rule_lock->actions;
2372 : QuerySource qsrc;
2373 : ListCell *r;
2374 :
2375 : /* Determine correct QuerySource value for actions */
2376 1500 : if (rule_lock->isInstead)
2377 : {
2378 1116 : if (event_qual != NULL)
2379 450 : qsrc = QSRC_QUAL_INSTEAD_RULE;
2380 : else
2381 : {
2382 666 : qsrc = QSRC_INSTEAD_RULE;
2383 666 : *instead_flag = true; /* report unqualified INSTEAD */
2384 : }
2385 : }
2386 : else
2387 384 : qsrc = QSRC_NON_INSTEAD_RULE;
2388 :
2389 1500 : if (qsrc == QSRC_QUAL_INSTEAD_RULE)
2390 : {
2391 : /*
2392 : * If there are INSTEAD rules with qualifications, the original
2393 : * query is still performed. But all the negated rule
2394 : * qualifications of the INSTEAD rules are added so it does its
2395 : * actions only in cases where the rule quals of all INSTEAD rules
2396 : * are false. Think of it as the default action in a case. We save
2397 : * this in *qual_product so RewriteQuery() can add it to the query
2398 : * list after we mangled it up enough.
2399 : *
2400 : * If we have already found an unqualified INSTEAD rule, then
2401 : * *qual_product won't be used, so don't bother building it.
2402 : */
2403 450 : if (!*instead_flag)
2404 : {
2405 444 : if (*qual_product == NULL)
2406 360 : *qual_product = copyObject(parsetree);
2407 444 : *qual_product = CopyAndAddInvertedQual(*qual_product,
2408 : event_qual,
2409 : rt_index,
2410 : event);
2411 : }
2412 : }
2413 :
2414 : /* Now process the rule's actions and add them to the result list */
2415 3048 : foreach(r, actions)
2416 : {
2417 1554 : Query *rule_action = lfirst(r);
2418 :
2419 1554 : if (rule_action->commandType == CMD_NOTHING)
2420 210 : continue;
2421 :
2422 1344 : rule_action = rewriteRuleAction(parsetree, rule_action,
2423 : event_qual, rt_index, event,
2424 : returning_flag);
2425 :
2426 1338 : rule_action->querySource = qsrc;
2427 1338 : rule_action->canSetTag = false; /* might change later */
2428 :
2429 1338 : results = lappend(results, rule_action);
2430 : }
2431 : }
2432 :
2433 91574 : return results;
2434 : }
2435 :
2436 :
2437 : /*
2438 : * get_view_query - get the Query from a view's _RETURN rule.
2439 : *
2440 : * Caller should have verified that the relation is a view, and therefore
2441 : * we should find an ON SELECT action.
2442 : *
2443 : * Note that the pointer returned is into the relcache and therefore must
2444 : * be treated as read-only to the caller and not modified or scribbled on.
2445 : */
2446 : Query *
2447 5548 : get_view_query(Relation view)
2448 : {
2449 : int i;
2450 :
2451 : Assert(view->rd_rel->relkind == RELKIND_VIEW);
2452 :
2453 5548 : for (i = 0; i < view->rd_rules->numLocks; i++)
2454 : {
2455 5548 : RewriteRule *rule = view->rd_rules->rules[i];
2456 :
2457 5548 : if (rule->event == CMD_SELECT)
2458 : {
2459 : /* A _RETURN rule should have only one action */
2460 5548 : if (list_length(rule->actions) != 1)
2461 0 : elog(ERROR, "invalid _RETURN rule action specification");
2462 :
2463 5548 : return (Query *) linitial(rule->actions);
2464 : }
2465 : }
2466 :
2467 0 : elog(ERROR, "failed to find _RETURN rule for view");
2468 : return NULL; /* keep compiler quiet */
2469 : }
2470 :
2471 :
2472 : /*
2473 : * view_has_instead_trigger - does view have an INSTEAD OF trigger for event?
2474 : *
2475 : * If it does, we don't want to treat it as auto-updatable. This test can't
2476 : * be folded into view_query_is_auto_updatable because it's not an error
2477 : * condition.
2478 : *
2479 : * For MERGE, this will return true if there is an INSTEAD OF trigger for
2480 : * every action in mergeActionList, and false if there are any actions that
2481 : * lack an INSTEAD OF trigger. If there are no data-modifying MERGE actions
2482 : * (only DO NOTHING actions), true is returned so that the view is treated
2483 : * as trigger-updatable, rather than erroring out if it's not auto-updatable.
2484 : */
2485 : bool
2486 5048 : view_has_instead_trigger(Relation view, CmdType event, List *mergeActionList)
2487 : {
2488 5048 : TriggerDesc *trigDesc = view->trigdesc;
2489 :
2490 5048 : switch (event)
2491 : {
2492 1626 : case CMD_INSERT:
2493 1626 : if (trigDesc && trigDesc->trig_insert_instead_row)
2494 264 : return true;
2495 1362 : break;
2496 1952 : case CMD_UPDATE:
2497 1952 : if (trigDesc && trigDesc->trig_update_instead_row)
2498 282 : return true;
2499 1670 : break;
2500 546 : case CMD_DELETE:
2501 546 : if (trigDesc && trigDesc->trig_delete_instead_row)
2502 108 : return true;
2503 438 : break;
2504 924 : case CMD_MERGE:
2505 1248 : foreach_node(MergeAction, action, mergeActionList)
2506 : {
2507 1008 : switch (action->commandType)
2508 : {
2509 168 : case CMD_INSERT:
2510 168 : if (!trigDesc || !trigDesc->trig_insert_instead_row)
2511 804 : return false;
2512 72 : break;
2513 696 : case CMD_UPDATE:
2514 696 : if (!trigDesc || !trigDesc->trig_update_instead_row)
2515 612 : return false;
2516 84 : break;
2517 120 : case CMD_DELETE:
2518 120 : if (!trigDesc || !trigDesc->trig_delete_instead_row)
2519 96 : return false;
2520 24 : break;
2521 24 : case CMD_NOTHING:
2522 : /* No trigger required */
2523 24 : break;
2524 0 : default:
2525 0 : elog(ERROR, "unrecognized commandType: %d", action->commandType);
2526 : break;
2527 : }
2528 : }
2529 120 : return true; /* no actions without an INSTEAD OF trigger */
2530 0 : default:
2531 0 : elog(ERROR, "unrecognized CmdType: %d", (int) event);
2532 : break;
2533 : }
2534 3470 : return false;
2535 : }
2536 :
2537 :
2538 : /*
2539 : * view_col_is_auto_updatable - test whether the specified column of a view
2540 : * is auto-updatable. Returns NULL (if the column can be updated) or a message
2541 : * string giving the reason that it cannot be.
2542 : *
2543 : * The returned string has not been translated; if it is shown as an error
2544 : * message, the caller should apply _() to translate it.
2545 : *
2546 : * Note that the checks performed here are local to this view. We do not check
2547 : * whether the referenced column of the underlying base relation is updatable.
2548 : */
2549 : static const char *
2550 12612 : view_col_is_auto_updatable(RangeTblRef *rtr, TargetEntry *tle)
2551 : {
2552 12612 : Var *var = (Var *) tle->expr;
2553 :
2554 : /*
2555 : * For now, the only updatable columns we support are those that are Vars
2556 : * referring to user columns of the underlying base relation.
2557 : *
2558 : * The view targetlist may contain resjunk columns (e.g., a view defined
2559 : * like "SELECT * FROM t ORDER BY a+b" is auto-updatable) but such columns
2560 : * are not auto-updatable, and in fact should never appear in the outer
2561 : * query's targetlist.
2562 : */
2563 12612 : if (tle->resjunk)
2564 180 : return gettext_noop("Junk view columns are not updatable.");
2565 :
2566 12432 : if (!IsA(var, Var) ||
2567 11634 : var->varno != rtr->rtindex ||
2568 11634 : var->varlevelsup != 0)
2569 798 : return gettext_noop("View columns that are not columns of their base relation are not updatable.");
2570 :
2571 11634 : if (var->varattno < 0)
2572 390 : return gettext_noop("View columns that refer to system columns are not updatable.");
2573 :
2574 11244 : if (var->varattno == 0)
2575 0 : return gettext_noop("View columns that return whole-row references are not updatable.");
2576 :
2577 11244 : return NULL; /* the view column is updatable */
2578 : }
2579 :
2580 :
2581 : /*
2582 : * view_query_is_auto_updatable - test whether the specified view definition
2583 : * represents an auto-updatable view. Returns NULL (if the view can be updated)
2584 : * or a message string giving the reason that it cannot be.
2585 :
2586 : * The returned string has not been translated; if it is shown as an error
2587 : * message, the caller should apply _() to translate it.
2588 : *
2589 : * If check_cols is true, the view is required to have at least one updatable
2590 : * column (necessary for INSERT/UPDATE). Otherwise the view's columns are not
2591 : * checked for updatability. See also view_cols_are_auto_updatable.
2592 : *
2593 : * Note that the checks performed here are only based on the view definition.
2594 : * We do not check whether any base relations referred to by the view are
2595 : * updatable.
2596 : */
2597 : const char *
2598 5326 : view_query_is_auto_updatable(Query *viewquery, bool check_cols)
2599 : {
2600 : RangeTblRef *rtr;
2601 : RangeTblEntry *base_rte;
2602 :
2603 : /*----------
2604 : * Check if the view is simply updatable. According to SQL-92 this means:
2605 : * - No DISTINCT clause.
2606 : * - Each TLE is a column reference, and each column appears at most once.
2607 : * - FROM contains exactly one base relation.
2608 : * - No GROUP BY or HAVING clauses.
2609 : * - No set operations (UNION, INTERSECT or EXCEPT).
2610 : * - No sub-queries in the WHERE clause that reference the target table.
2611 : *
2612 : * We ignore that last restriction since it would be complex to enforce
2613 : * and there isn't any actual benefit to disallowing sub-queries. (The
2614 : * semantic issues that the standard is presumably concerned about don't
2615 : * arise in Postgres, since any such sub-query will not see any updates
2616 : * executed by the outer query anyway, thanks to MVCC snapshotting.)
2617 : *
2618 : * We also relax the second restriction by supporting part of SQL:1999
2619 : * feature T111, which allows for a mix of updatable and non-updatable
2620 : * columns, provided that an INSERT or UPDATE doesn't attempt to assign to
2621 : * a non-updatable column.
2622 : *
2623 : * In addition we impose these constraints, involving features that are
2624 : * not part of SQL-92:
2625 : * - No CTEs (WITH clauses).
2626 : * - No OFFSET or LIMIT clauses (this matches a SQL:2008 restriction).
2627 : * - No system columns (including whole-row references) in the tlist.
2628 : * - No window functions in the tlist.
2629 : * - No set-returning functions in the tlist.
2630 : *
2631 : * Note that we do these checks without recursively expanding the view.
2632 : * If the base relation is a view, we'll recursively deal with it later.
2633 : *----------
2634 : */
2635 5326 : if (viewquery->distinctClause != NIL)
2636 72 : return gettext_noop("Views containing DISTINCT are not automatically updatable.");
2637 :
2638 5254 : if (viewquery->groupClause != NIL || viewquery->groupingSets)
2639 36 : return gettext_noop("Views containing GROUP BY are not automatically updatable.");
2640 :
2641 5218 : if (viewquery->havingQual != NULL)
2642 30 : return gettext_noop("Views containing HAVING are not automatically updatable.");
2643 :
2644 5188 : if (viewquery->setOperations != NULL)
2645 36 : return gettext_noop("Views containing UNION, INTERSECT, or EXCEPT are not automatically updatable.");
2646 :
2647 5152 : if (viewquery->cteList != NIL)
2648 36 : return gettext_noop("Views containing WITH are not automatically updatable.");
2649 :
2650 5116 : if (viewquery->limitOffset != NULL || viewquery->limitCount != NULL)
2651 504 : return gettext_noop("Views containing LIMIT or OFFSET are not automatically updatable.");
2652 :
2653 : /*
2654 : * We must not allow window functions or set returning functions in the
2655 : * targetlist. Otherwise we might end up inserting them into the quals of
2656 : * the main query. We must also check for aggregates in the targetlist in
2657 : * case they appear without a GROUP BY.
2658 : *
2659 : * These restrictions ensure that each row of the view corresponds to a
2660 : * unique row in the underlying base relation.
2661 : */
2662 4612 : if (viewquery->hasAggs)
2663 30 : return gettext_noop("Views that return aggregate functions are not automatically updatable.");
2664 :
2665 4582 : if (viewquery->hasWindowFuncs)
2666 36 : return gettext_noop("Views that return window functions are not automatically updatable.");
2667 :
2668 4546 : if (viewquery->hasTargetSRFs)
2669 42 : return gettext_noop("Views that return set-returning functions are not automatically updatable.");
2670 :
2671 : /*
2672 : * The view query should select from a single base relation, which must be
2673 : * a table or another view.
2674 : */
2675 4504 : if (list_length(viewquery->jointree->fromlist) != 1)
2676 66 : return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
2677 :
2678 4438 : rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist);
2679 4438 : if (!IsA(rtr, RangeTblRef))
2680 0 : return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
2681 :
2682 4438 : base_rte = rt_fetch(rtr->rtindex, viewquery->rtable);
2683 4438 : if (base_rte->rtekind != RTE_RELATION ||
2684 4324 : (base_rte->relkind != RELKIND_RELATION &&
2685 1658 : base_rte->relkind != RELKIND_FOREIGN_TABLE &&
2686 1636 : base_rte->relkind != RELKIND_VIEW &&
2687 190 : base_rte->relkind != RELKIND_PARTITIONED_TABLE))
2688 156 : return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
2689 :
2690 4282 : if (base_rte->tablesample)
2691 6 : return gettext_noop("Views containing TABLESAMPLE are not automatically updatable.");
2692 :
2693 : /*
2694 : * Check that the view has at least one updatable column. This is required
2695 : * for INSERT/UPDATE but not for DELETE.
2696 : */
2697 4276 : if (check_cols)
2698 : {
2699 : ListCell *cell;
2700 : bool found;
2701 :
2702 2962 : found = false;
2703 3136 : foreach(cell, viewquery->targetList)
2704 : {
2705 3136 : TargetEntry *tle = (TargetEntry *) lfirst(cell);
2706 :
2707 3136 : if (view_col_is_auto_updatable(rtr, tle) == NULL)
2708 : {
2709 2962 : found = true;
2710 2962 : break;
2711 : }
2712 : }
2713 :
2714 2962 : if (!found)
2715 0 : return gettext_noop("Views that have no updatable columns are not automatically updatable.");
2716 : }
2717 :
2718 4276 : return NULL; /* the view is updatable */
2719 : }
2720 :
2721 :
2722 : /*
2723 : * view_cols_are_auto_updatable - test whether all of the required columns of
2724 : * an auto-updatable view are actually updatable. Returns NULL (if all the
2725 : * required columns can be updated) or a message string giving the reason that
2726 : * they cannot be.
2727 : *
2728 : * The returned string has not been translated; if it is shown as an error
2729 : * message, the caller should apply _() to translate it.
2730 : *
2731 : * This should be used for INSERT/UPDATE to ensure that we don't attempt to
2732 : * assign to any non-updatable columns.
2733 : *
2734 : * Additionally it may be used to retrieve the set of updatable columns in the
2735 : * view, or if one or more of the required columns is not updatable, the name
2736 : * of the first offending non-updatable column.
2737 : *
2738 : * The caller must have already verified that this is an auto-updatable view
2739 : * using view_query_is_auto_updatable.
2740 : *
2741 : * Note that the checks performed here are only based on the view definition.
2742 : * We do not check whether the referenced columns of the base relation are
2743 : * updatable.
2744 : */
2745 : static const char *
2746 3782 : view_cols_are_auto_updatable(Query *viewquery,
2747 : Bitmapset *required_cols,
2748 : Bitmapset **updatable_cols,
2749 : char **non_updatable_col)
2750 : {
2751 : RangeTblRef *rtr;
2752 : AttrNumber col;
2753 : ListCell *cell;
2754 :
2755 : /*
2756 : * The caller should have verified that this view is auto-updatable and so
2757 : * there should be a single base relation.
2758 : */
2759 : Assert(list_length(viewquery->jointree->fromlist) == 1);
2760 3782 : rtr = linitial_node(RangeTblRef, viewquery->jointree->fromlist);
2761 :
2762 : /* Initialize the optional return values */
2763 3782 : if (updatable_cols != NULL)
2764 966 : *updatable_cols = NULL;
2765 3782 : if (non_updatable_col != NULL)
2766 2816 : *non_updatable_col = NULL;
2767 :
2768 : /* Test each view column for updatability */
2769 3782 : col = -FirstLowInvalidHeapAttributeNumber;
2770 13144 : foreach(cell, viewquery->targetList)
2771 : {
2772 9476 : TargetEntry *tle = (TargetEntry *) lfirst(cell);
2773 : const char *col_update_detail;
2774 :
2775 9476 : col++;
2776 9476 : col_update_detail = view_col_is_auto_updatable(rtr, tle);
2777 :
2778 9476 : if (col_update_detail == NULL)
2779 : {
2780 : /* The column is updatable */
2781 8282 : if (updatable_cols != NULL)
2782 1758 : *updatable_cols = bms_add_member(*updatable_cols, col);
2783 : }
2784 1194 : else if (bms_is_member(col, required_cols))
2785 : {
2786 : /* The required column is not updatable */
2787 114 : if (non_updatable_col != NULL)
2788 114 : *non_updatable_col = tle->resname;
2789 114 : return col_update_detail;
2790 : }
2791 : }
2792 :
2793 3668 : return NULL; /* all the required view columns are updatable */
2794 : }
2795 :
2796 :
2797 : /*
2798 : * relation_is_updatable - determine which update events the specified
2799 : * relation supports.
2800 : *
2801 : * Note that views may contain a mix of updatable and non-updatable columns.
2802 : * For a view to support INSERT/UPDATE it must have at least one updatable
2803 : * column, but there is no such restriction for DELETE. If include_cols is
2804 : * non-NULL, then only the specified columns are considered when testing for
2805 : * updatability.
2806 : *
2807 : * Unlike the preceding functions, this does recurse to look at a view's
2808 : * base relations, so it needs to detect recursion. To do that, we pass
2809 : * a list of currently-considered outer relations. External callers need
2810 : * only pass NIL.
2811 : *
2812 : * This is used for the information_schema views, which have separate concepts
2813 : * of "updatable" and "trigger updatable". A relation is "updatable" if it
2814 : * can be updated without the need for triggers (either because it has a
2815 : * suitable RULE, or because it is simple enough to be automatically updated).
2816 : * A relation is "trigger updatable" if it has a suitable INSTEAD OF trigger.
2817 : * The SQL standard regards this as not necessarily updatable, presumably
2818 : * because there is no way of knowing what the trigger will actually do.
2819 : * The information_schema views therefore call this function with
2820 : * include_triggers = false. However, other callers might only care whether
2821 : * data-modifying SQL will work, so they can pass include_triggers = true
2822 : * to have trigger updatability included in the result.
2823 : *
2824 : * The return value is a bitmask of rule event numbers indicating which of
2825 : * the INSERT, UPDATE and DELETE operations are supported. (We do it this way
2826 : * so that we can test for UPDATE plus DELETE support in a single call.)
2827 : */
2828 : int
2829 1956 : relation_is_updatable(Oid reloid,
2830 : List *outer_reloids,
2831 : bool include_triggers,
2832 : Bitmapset *include_cols)
2833 : {
2834 1956 : int events = 0;
2835 : Relation rel;
2836 : RuleLock *rulelocks;
2837 :
2838 : #define ALL_EVENTS ((1 << CMD_INSERT) | (1 << CMD_UPDATE) | (1 << CMD_DELETE))
2839 :
2840 : /* Since this function recurses, it could be driven to stack overflow */
2841 1956 : check_stack_depth();
2842 :
2843 1956 : rel = try_relation_open(reloid, AccessShareLock);
2844 :
2845 : /*
2846 : * If the relation doesn't exist, return zero rather than throwing an
2847 : * error. This is helpful since scanning an information_schema view under
2848 : * MVCC rules can result in referencing rels that have actually been
2849 : * deleted already.
2850 : */
2851 1956 : if (rel == NULL)
2852 0 : return 0;
2853 :
2854 : /* If we detect a recursive view, report that it is not updatable */
2855 1956 : if (list_member_oid(outer_reloids, RelationGetRelid(rel)))
2856 : {
2857 0 : relation_close(rel, AccessShareLock);
2858 0 : return 0;
2859 : }
2860 :
2861 : /* If the relation is a table, it is always updatable */
2862 1956 : if (rel->rd_rel->relkind == RELKIND_RELATION ||
2863 1956 : rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
2864 : {
2865 18 : relation_close(rel, AccessShareLock);
2866 18 : return ALL_EVENTS;
2867 : }
2868 :
2869 : /* Look for unconditional DO INSTEAD rules, and note supported events */
2870 1938 : rulelocks = rel->rd_rules;
2871 1938 : if (rulelocks != NULL)
2872 : {
2873 : int i;
2874 :
2875 4248 : for (i = 0; i < rulelocks->numLocks; i++)
2876 : {
2877 2310 : if (rulelocks->rules[i]->isInstead &&
2878 2298 : rulelocks->rules[i]->qual == NULL)
2879 : {
2880 2298 : events |= ((1 << rulelocks->rules[i]->event) & ALL_EVENTS);
2881 : }
2882 : }
2883 :
2884 : /* If we have rules for all events, we're done */
2885 1938 : if (events == ALL_EVENTS)
2886 : {
2887 60 : relation_close(rel, AccessShareLock);
2888 60 : return events;
2889 : }
2890 : }
2891 :
2892 : /* Similarly look for INSTEAD OF triggers, if they are to be included */
2893 1878 : if (include_triggers)
2894 : {
2895 0 : TriggerDesc *trigDesc = rel->trigdesc;
2896 :
2897 0 : if (trigDesc)
2898 : {
2899 0 : if (trigDesc->trig_insert_instead_row)
2900 0 : events |= (1 << CMD_INSERT);
2901 0 : if (trigDesc->trig_update_instead_row)
2902 0 : events |= (1 << CMD_UPDATE);
2903 0 : if (trigDesc->trig_delete_instead_row)
2904 0 : events |= (1 << CMD_DELETE);
2905 :
2906 : /* If we have triggers for all events, we're done */
2907 0 : if (events == ALL_EVENTS)
2908 : {
2909 0 : relation_close(rel, AccessShareLock);
2910 0 : return events;
2911 : }
2912 : }
2913 : }
2914 :
2915 : /* If this is a foreign table, check which update events it supports */
2916 1878 : if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
2917 : {
2918 0 : FdwRoutine *fdwroutine = GetFdwRoutineForRelation(rel, false);
2919 :
2920 0 : if (fdwroutine->IsForeignRelUpdatable != NULL)
2921 0 : events |= fdwroutine->IsForeignRelUpdatable(rel);
2922 : else
2923 : {
2924 : /* Assume presence of executor functions is sufficient */
2925 0 : if (fdwroutine->ExecForeignInsert != NULL)
2926 0 : events |= (1 << CMD_INSERT);
2927 0 : if (fdwroutine->ExecForeignUpdate != NULL)
2928 0 : events |= (1 << CMD_UPDATE);
2929 0 : if (fdwroutine->ExecForeignDelete != NULL)
2930 0 : events |= (1 << CMD_DELETE);
2931 : }
2932 :
2933 0 : relation_close(rel, AccessShareLock);
2934 0 : return events;
2935 : }
2936 :
2937 : /* Check if this is an automatically updatable view */
2938 1878 : if (rel->rd_rel->relkind == RELKIND_VIEW)
2939 : {
2940 1878 : Query *viewquery = get_view_query(rel);
2941 :
2942 1878 : if (view_query_is_auto_updatable(viewquery, false) == NULL)
2943 : {
2944 : Bitmapset *updatable_cols;
2945 : int auto_events;
2946 : RangeTblRef *rtr;
2947 : RangeTblEntry *base_rte;
2948 : Oid baseoid;
2949 :
2950 : /*
2951 : * Determine which of the view's columns are updatable. If there
2952 : * are none within the set of columns we are looking at, then the
2953 : * view doesn't support INSERT/UPDATE, but it may still support
2954 : * DELETE.
2955 : */
2956 966 : view_cols_are_auto_updatable(viewquery, NULL,
2957 : &updatable_cols, NULL);
2958 :
2959 966 : if (include_cols != NULL)
2960 498 : updatable_cols = bms_int_members(updatable_cols, include_cols);
2961 :
2962 966 : if (bms_is_empty(updatable_cols))
2963 102 : auto_events = (1 << CMD_DELETE); /* May support DELETE */
2964 : else
2965 864 : auto_events = ALL_EVENTS; /* May support all events */
2966 :
2967 : /*
2968 : * The base relation must also support these update commands.
2969 : * Tables are always updatable, but for any other kind of base
2970 : * relation we must do a recursive check limited to the columns
2971 : * referenced by the locally updatable columns in this view.
2972 : */
2973 966 : rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist);
2974 966 : base_rte = rt_fetch(rtr->rtindex, viewquery->rtable);
2975 : Assert(base_rte->rtekind == RTE_RELATION);
2976 :
2977 966 : if (base_rte->relkind != RELKIND_RELATION &&
2978 522 : base_rte->relkind != RELKIND_PARTITIONED_TABLE)
2979 : {
2980 492 : baseoid = base_rte->relid;
2981 492 : outer_reloids = lappend_oid(outer_reloids,
2982 : RelationGetRelid(rel));
2983 492 : include_cols = adjust_view_column_set(updatable_cols,
2984 : viewquery->targetList);
2985 492 : auto_events &= relation_is_updatable(baseoid,
2986 : outer_reloids,
2987 : include_triggers,
2988 : include_cols);
2989 492 : outer_reloids = list_delete_last(outer_reloids);
2990 : }
2991 966 : events |= auto_events;
2992 : }
2993 : }
2994 :
2995 : /* If we reach here, the relation may support some update commands */
2996 1878 : relation_close(rel, AccessShareLock);
2997 1878 : return events;
2998 : }
2999 :
3000 :
3001 : /*
3002 : * adjust_view_column_set - map a set of column numbers according to targetlist
3003 : *
3004 : * This is used with simply-updatable views to map column-permissions sets for
3005 : * the view columns onto the matching columns in the underlying base relation.
3006 : * The targetlist is expected to be a list of plain Vars of the underlying
3007 : * relation (as per the checks above in view_query_is_auto_updatable).
3008 : */
3009 : static Bitmapset *
3010 6580 : adjust_view_column_set(Bitmapset *cols, List *targetlist)
3011 : {
3012 6580 : Bitmapset *result = NULL;
3013 : int col;
3014 :
3015 6580 : col = -1;
3016 11296 : while ((col = bms_next_member(cols, col)) >= 0)
3017 : {
3018 : /* bit numbers are offset by FirstLowInvalidHeapAttributeNumber */
3019 4716 : AttrNumber attno = col + FirstLowInvalidHeapAttributeNumber;
3020 :
3021 4716 : if (attno == InvalidAttrNumber)
3022 : {
3023 : /*
3024 : * There's a whole-row reference to the view. For permissions
3025 : * purposes, treat it as a reference to each column available from
3026 : * the view. (We should *not* convert this to a whole-row
3027 : * reference to the base relation, since the view may not touch
3028 : * all columns of the base relation.)
3029 : */
3030 : ListCell *lc;
3031 :
3032 0 : foreach(lc, targetlist)
3033 : {
3034 0 : TargetEntry *tle = lfirst_node(TargetEntry, lc);
3035 : Var *var;
3036 :
3037 0 : if (tle->resjunk)
3038 0 : continue;
3039 0 : var = castNode(Var, tle->expr);
3040 0 : result = bms_add_member(result,
3041 0 : var->varattno - FirstLowInvalidHeapAttributeNumber);
3042 : }
3043 : }
3044 : else
3045 : {
3046 : /*
3047 : * Views do not have system columns, so we do not expect to see
3048 : * any other system attnos here. If we do find one, the error
3049 : * case will apply.
3050 : */
3051 4716 : TargetEntry *tle = get_tle_by_resno(targetlist, attno);
3052 :
3053 4716 : if (tle != NULL && !tle->resjunk && IsA(tle->expr, Var))
3054 4716 : {
3055 4716 : Var *var = (Var *) tle->expr;
3056 :
3057 4716 : result = bms_add_member(result,
3058 4716 : var->varattno - FirstLowInvalidHeapAttributeNumber);
3059 : }
3060 : else
3061 0 : elog(ERROR, "attribute number %d not found in view targetlist",
3062 : attno);
3063 : }
3064 : }
3065 :
3066 6580 : return result;
3067 : }
3068 :
3069 :
3070 : /*
3071 : * error_view_not_updatable -
3072 : * Report an error due to an attempt to update a non-updatable view.
3073 : *
3074 : * Generally this is expected to be called from the rewriter, with suitable
3075 : * error detail explaining why the view is not updatable. Note, however, that
3076 : * the executor also performs a just-in-case check that the target view is
3077 : * updatable. That check is expected to never fail, but if it does, it will
3078 : * call this function with NULL error detail --- see CheckValidResultRel().
3079 : *
3080 : * Note: for MERGE, at least one of the actions in mergeActionList is expected
3081 : * to lack a suitable INSTEAD OF trigger --- see view_has_instead_trigger().
3082 : */
3083 : void
3084 156 : error_view_not_updatable(Relation view,
3085 : CmdType command,
3086 : List *mergeActionList,
3087 : const char *detail)
3088 : {
3089 156 : TriggerDesc *trigDesc = view->trigdesc;
3090 :
3091 156 : switch (command)
3092 : {
3093 24 : case CMD_INSERT:
3094 24 : ereport(ERROR,
3095 : errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
3096 : errmsg("cannot insert into view \"%s\"",
3097 : RelationGetRelationName(view)),
3098 : detail ? errdetail_internal("%s", _(detail)) : 0,
3099 : errhint("To enable inserting into the view, provide an INSTEAD OF INSERT trigger or an unconditional ON INSERT DO INSTEAD rule."));
3100 : break;
3101 54 : case CMD_UPDATE:
3102 54 : ereport(ERROR,
3103 : errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
3104 : errmsg("cannot update view \"%s\"",
3105 : RelationGetRelationName(view)),
3106 : detail ? errdetail_internal("%s", _(detail)) : 0,
3107 : errhint("To enable updating the view, provide an INSTEAD OF UPDATE trigger or an unconditional ON UPDATE DO INSTEAD rule."));
3108 : break;
3109 48 : case CMD_DELETE:
3110 48 : ereport(ERROR,
3111 : errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
3112 : errmsg("cannot delete from view \"%s\"",
3113 : RelationGetRelationName(view)),
3114 : detail ? errdetail_internal("%s", _(detail)) : 0,
3115 : errhint("To enable deleting from the view, provide an INSTEAD OF DELETE trigger or an unconditional ON DELETE DO INSTEAD rule."));
3116 : break;
3117 30 : case CMD_MERGE:
3118 :
3119 : /*
3120 : * Note that the error hints here differ from above, since MERGE
3121 : * doesn't support rules.
3122 : */
3123 36 : foreach_node(MergeAction, action, mergeActionList)
3124 : {
3125 36 : switch (action->commandType)
3126 : {
3127 12 : case CMD_INSERT:
3128 12 : if (!trigDesc || !trigDesc->trig_insert_instead_row)
3129 12 : ereport(ERROR,
3130 : errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
3131 : errmsg("cannot insert into view \"%s\"",
3132 : RelationGetRelationName(view)),
3133 : detail ? errdetail_internal("%s", _(detail)) : 0,
3134 : errhint("To enable inserting into the view using MERGE, provide an INSTEAD OF INSERT trigger."));
3135 0 : break;
3136 12 : case CMD_UPDATE:
3137 12 : if (!trigDesc || !trigDesc->trig_update_instead_row)
3138 6 : ereport(ERROR,
3139 : errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
3140 : errmsg("cannot update view \"%s\"",
3141 : RelationGetRelationName(view)),
3142 : detail ? errdetail_internal("%s", _(detail)) : 0,
3143 : errhint("To enable updating the view using MERGE, provide an INSTEAD OF UPDATE trigger."));
3144 6 : break;
3145 12 : case CMD_DELETE:
3146 12 : if (!trigDesc || !trigDesc->trig_delete_instead_row)
3147 12 : ereport(ERROR,
3148 : errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
3149 : errmsg("cannot delete from view \"%s\"",
3150 : RelationGetRelationName(view)),
3151 : detail ? errdetail_internal("%s", _(detail)) : 0,
3152 : errhint("To enable deleting from the view using MERGE, provide an INSTEAD OF DELETE trigger."));
3153 0 : break;
3154 0 : case CMD_NOTHING:
3155 0 : break;
3156 0 : default:
3157 0 : elog(ERROR, "unrecognized commandType: %d", action->commandType);
3158 : break;
3159 : }
3160 : }
3161 0 : break;
3162 0 : default:
3163 0 : elog(ERROR, "unrecognized CmdType: %d", (int) command);
3164 : break;
3165 : }
3166 0 : }
3167 :
3168 :
3169 : /*
3170 : * rewriteTargetView -
3171 : * Attempt to rewrite a query where the target relation is a view, so that
3172 : * the view's base relation becomes the target relation.
3173 : *
3174 : * Note that the base relation here may itself be a view, which may or may not
3175 : * have INSTEAD OF triggers or rules to handle the update. That is handled by
3176 : * the recursion in RewriteQuery.
3177 : */
3178 : static Query *
3179 3302 : rewriteTargetView(Query *parsetree, Relation view)
3180 : {
3181 : Query *viewquery;
3182 : bool insert_or_update;
3183 : const char *auto_update_detail;
3184 : RangeTblRef *rtr;
3185 : int base_rt_index;
3186 : int new_rt_index;
3187 : RangeTblEntry *base_rte;
3188 : RangeTblEntry *view_rte;
3189 : RangeTblEntry *new_rte;
3190 : RTEPermissionInfo *base_perminfo;
3191 : RTEPermissionInfo *view_perminfo;
3192 : RTEPermissionInfo *new_perminfo;
3193 : Relation base_rel;
3194 : List *view_targetlist;
3195 : ListCell *lc;
3196 :
3197 : /*
3198 : * Get the Query from the view's ON SELECT rule. We're going to munge the
3199 : * Query to change the view's base relation into the target relation,
3200 : * along with various other changes along the way, so we need to make a
3201 : * copy of it (get_view_query() returns a pointer into the relcache, so we
3202 : * have to treat it as read-only).
3203 : */
3204 3302 : viewquery = copyObject(get_view_query(view));
3205 :
3206 : /*
3207 : * Are we doing INSERT/UPDATE, or MERGE containing INSERT/UPDATE? If so,
3208 : * various additional checks on the view columns need to be applied, and
3209 : * any view CHECK OPTIONs need to be enforced.
3210 : */
3211 3302 : insert_or_update =
3212 5476 : (parsetree->commandType == CMD_INSERT ||
3213 2174 : parsetree->commandType == CMD_UPDATE);
3214 :
3215 3302 : if (parsetree->commandType == CMD_MERGE)
3216 : {
3217 1704 : foreach_node(MergeAction, action, parsetree->mergeActionList)
3218 : {
3219 840 : if (action->commandType == CMD_INSERT ||
3220 756 : action->commandType == CMD_UPDATE)
3221 : {
3222 744 : insert_or_update = true;
3223 744 : break;
3224 : }
3225 : }
3226 : }
3227 :
3228 : /*
3229 : * The view must be updatable, else fail.
3230 : *
3231 : * If we are doing INSERT/UPDATE (or MERGE containing INSERT/UPDATE), we
3232 : * also check that there is at least one updatable column.
3233 : */
3234 : auto_update_detail =
3235 3302 : view_query_is_auto_updatable(viewquery, insert_or_update);
3236 :
3237 3302 : if (auto_update_detail)
3238 138 : error_view_not_updatable(view,
3239 : parsetree->commandType,
3240 : parsetree->mergeActionList,
3241 : auto_update_detail);
3242 :
3243 : /*
3244 : * For INSERT/UPDATE (or MERGE containing INSERT/UPDATE) the modified
3245 : * columns must all be updatable. Note that we get the modified columns
3246 : * from the query's targetlist, not from the result RTE's insertedCols
3247 : * and/or updatedCols set, since rewriteTargetListIU may have added
3248 : * additional targetlist entries for view defaults, and these must also be
3249 : * updatable.
3250 : */
3251 3164 : if (insert_or_update)
3252 : {
3253 2816 : Bitmapset *modified_cols = NULL;
3254 : char *non_updatable_col;
3255 :
3256 5954 : foreach(lc, parsetree->targetList)
3257 : {
3258 3138 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
3259 :
3260 3138 : if (!tle->resjunk)
3261 3138 : modified_cols = bms_add_member(modified_cols,
3262 3138 : tle->resno - FirstLowInvalidHeapAttributeNumber);
3263 : }
3264 :
3265 2816 : if (parsetree->onConflict)
3266 : {
3267 324 : foreach(lc, parsetree->onConflict->onConflictSet)
3268 : {
3269 156 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
3270 :
3271 156 : if (!tle->resjunk)
3272 156 : modified_cols = bms_add_member(modified_cols,
3273 156 : tle->resno - FirstLowInvalidHeapAttributeNumber);
3274 : }
3275 : }
3276 :
3277 6478 : foreach_node(MergeAction, action, parsetree->mergeActionList)
3278 : {
3279 846 : if (action->commandType == CMD_INSERT ||
3280 684 : action->commandType == CMD_UPDATE)
3281 : {
3282 2586 : foreach_node(TargetEntry, tle, action->targetList)
3283 : {
3284 978 : if (!tle->resjunk)
3285 978 : modified_cols = bms_add_member(modified_cols,
3286 978 : tle->resno - FirstLowInvalidHeapAttributeNumber);
3287 : }
3288 : }
3289 : }
3290 :
3291 2816 : auto_update_detail = view_cols_are_auto_updatable(viewquery,
3292 : modified_cols,
3293 : NULL,
3294 : &non_updatable_col);
3295 2816 : if (auto_update_detail)
3296 : {
3297 : /*
3298 : * This is a different error, caused by an attempt to update a
3299 : * non-updatable column in an otherwise updatable view.
3300 : */
3301 114 : switch (parsetree->commandType)
3302 : {
3303 66 : case CMD_INSERT:
3304 66 : ereport(ERROR,
3305 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3306 : errmsg("cannot insert into column \"%s\" of view \"%s\"",
3307 : non_updatable_col,
3308 : RelationGetRelationName(view)),
3309 : errdetail_internal("%s", _(auto_update_detail))));
3310 : break;
3311 42 : case CMD_UPDATE:
3312 42 : ereport(ERROR,
3313 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3314 : errmsg("cannot update column \"%s\" of view \"%s\"",
3315 : non_updatable_col,
3316 : RelationGetRelationName(view)),
3317 : errdetail_internal("%s", _(auto_update_detail))));
3318 : break;
3319 6 : case CMD_MERGE:
3320 6 : ereport(ERROR,
3321 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3322 : errmsg("cannot merge into column \"%s\" of view \"%s\"",
3323 : non_updatable_col,
3324 : RelationGetRelationName(view)),
3325 : errdetail_internal("%s", _(auto_update_detail))));
3326 : break;
3327 0 : default:
3328 0 : elog(ERROR, "unrecognized CmdType: %d",
3329 : (int) parsetree->commandType);
3330 : break;
3331 : }
3332 2702 : }
3333 : }
3334 :
3335 : /*
3336 : * For MERGE, there must not be any INSTEAD OF triggers on an otherwise
3337 : * updatable view. The caller already checked that there isn't a full set
3338 : * of INSTEAD OF triggers, so this is to guard against having a partial
3339 : * set (mixing auto-update and trigger-update actions in a single command
3340 : * isn't supported).
3341 : */
3342 3050 : if (parsetree->commandType == CMD_MERGE)
3343 : {
3344 2406 : foreach_node(MergeAction, action, parsetree->mergeActionList)
3345 : {
3346 1764 : if (action->commandType != CMD_NOTHING &&
3347 882 : view_has_instead_trigger(view, action->commandType, NIL))
3348 6 : ereport(ERROR,
3349 : errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3350 : errmsg("cannot merge into view \"%s\"",
3351 : RelationGetRelationName(view)),
3352 : errdetail("MERGE is not supported for views with INSTEAD OF triggers for some actions, but not others."),
3353 : errhint("To enable merging into the view, either provide a full set of INSTEAD OF triggers or drop the existing INSTEAD OF triggers."));
3354 : }
3355 : }
3356 :
3357 : /* Locate RTE describing the view in the outer query */
3358 3044 : view_rte = rt_fetch(parsetree->resultRelation, parsetree->rtable);
3359 :
3360 : /*
3361 : * If we get here, view_query_is_auto_updatable() has verified that the
3362 : * view contains a single base relation.
3363 : */
3364 : Assert(list_length(viewquery->jointree->fromlist) == 1);
3365 3044 : rtr = linitial_node(RangeTblRef, viewquery->jointree->fromlist);
3366 :
3367 3044 : base_rt_index = rtr->rtindex;
3368 3044 : base_rte = rt_fetch(base_rt_index, viewquery->rtable);
3369 : Assert(base_rte->rtekind == RTE_RELATION);
3370 3044 : base_perminfo = getRTEPermissionInfo(viewquery->rteperminfos, base_rte);
3371 :
3372 : /*
3373 : * Up to now, the base relation hasn't been touched at all in our query.
3374 : * We need to acquire lock on it before we try to do anything with it.
3375 : * (The subsequent recursive call of RewriteQuery will suppose that we
3376 : * already have the right lock!) Since it will become the query target
3377 : * relation, RowExclusiveLock is always the right thing.
3378 : */
3379 3044 : base_rel = table_open(base_rte->relid, RowExclusiveLock);
3380 :
3381 : /*
3382 : * While we have the relation open, update the RTE's relkind, just in case
3383 : * it changed since this view was made (cf. AcquireRewriteLocks).
3384 : */
3385 3044 : base_rte->relkind = base_rel->rd_rel->relkind;
3386 :
3387 : /*
3388 : * If the view query contains any sublink subqueries then we need to also
3389 : * acquire locks on any relations they refer to. We know that there won't
3390 : * be any subqueries in the range table or CTEs, so we can skip those, as
3391 : * in AcquireRewriteLocks.
3392 : */
3393 3044 : if (viewquery->hasSubLinks)
3394 : {
3395 : acquireLocksOnSubLinks_context context;
3396 :
3397 174 : context.for_execute = true;
3398 174 : query_tree_walker(viewquery, acquireLocksOnSubLinks, &context,
3399 : QTW_IGNORE_RC_SUBQUERIES);
3400 : }
3401 :
3402 : /*
3403 : * Create a new target RTE describing the base relation, and add it to the
3404 : * outer query's rangetable. (What's happening in the next few steps is
3405 : * very much like what the planner would do to "pull up" the view into the
3406 : * outer query. Perhaps someday we should refactor things enough so that
3407 : * we can share code with the planner.)
3408 : *
3409 : * Be sure to set rellockmode to the correct thing for the target table.
3410 : * Since we copied the whole viewquery above, we can just scribble on
3411 : * base_rte instead of copying it.
3412 : */
3413 3044 : new_rte = base_rte;
3414 3044 : new_rte->rellockmode = RowExclusiveLock;
3415 :
3416 3044 : parsetree->rtable = lappend(parsetree->rtable, new_rte);
3417 3044 : new_rt_index = list_length(parsetree->rtable);
3418 :
3419 : /*
3420 : * INSERTs never inherit. For UPDATE/DELETE/MERGE, we use the view
3421 : * query's inheritance flag for the base relation.
3422 : */
3423 3044 : if (parsetree->commandType == CMD_INSERT)
3424 1044 : new_rte->inh = false;
3425 :
3426 : /*
3427 : * Adjust the view's targetlist Vars to reference the new target RTE, ie
3428 : * make their varnos be new_rt_index instead of base_rt_index. There can
3429 : * be no Vars for other rels in the tlist, so this is sufficient to pull
3430 : * up the tlist expressions for use in the outer query. The tlist will
3431 : * provide the replacement expressions used by ReplaceVarsFromTargetList
3432 : * below.
3433 : */
3434 3044 : view_targetlist = viewquery->targetList;
3435 :
3436 3044 : ChangeVarNodes((Node *) view_targetlist,
3437 : base_rt_index,
3438 : new_rt_index,
3439 : 0);
3440 :
3441 : /*
3442 : * If the view has "security_invoker" set, mark the new target relation
3443 : * for the permissions checks that we want to enforce against the query
3444 : * caller. Otherwise we want to enforce them against the view owner.
3445 : *
3446 : * At the relation level, require the same INSERT/UPDATE/DELETE
3447 : * permissions that the query caller needs against the view. We drop the
3448 : * ACL_SELECT bit that is presumably in new_perminfo->requiredPerms
3449 : * initially.
3450 : *
3451 : * Note: the original view's RTEPermissionInfo remains in the query's
3452 : * rteperminfos so that the executor still performs appropriate
3453 : * permissions checks for the query caller's use of the view.
3454 : */
3455 3044 : view_perminfo = getRTEPermissionInfo(parsetree->rteperminfos, view_rte);
3456 :
3457 : /*
3458 : * Disregard the perminfo in viewquery->rteperminfos that the base_rte
3459 : * would currently be pointing at, because we'd like it to point now to a
3460 : * new one that will be filled below. Must set perminfoindex to 0 to not
3461 : * trip over the Assert in addRTEPermissionInfo().
3462 : */
3463 3044 : new_rte->perminfoindex = 0;
3464 3044 : new_perminfo = addRTEPermissionInfo(&parsetree->rteperminfos, new_rte);
3465 3044 : if (RelationHasSecurityInvoker(view))
3466 486 : new_perminfo->checkAsUser = InvalidOid;
3467 : else
3468 2558 : new_perminfo->checkAsUser = view->rd_rel->relowner;
3469 3044 : new_perminfo->requiredPerms = view_perminfo->requiredPerms;
3470 :
3471 : /*
3472 : * Now for the per-column permissions bits.
3473 : *
3474 : * Initially, new_perminfo (base_perminfo) contains selectedCols
3475 : * permission check bits for all base-rel columns referenced by the view,
3476 : * but since the view is a SELECT query its insertedCols/updatedCols is
3477 : * empty. We set insertedCols and updatedCols to include all the columns
3478 : * the outer query is trying to modify, adjusting the column numbers as
3479 : * needed. But we leave selectedCols as-is, so the view owner must have
3480 : * read permission for all columns used in the view definition, even if
3481 : * some of them are not read by the outer query. We could try to limit
3482 : * selectedCols to only columns used in the transformed query, but that
3483 : * does not correspond to what happens in ordinary SELECT usage of a view:
3484 : * all referenced columns must have read permission, even if optimization
3485 : * finds that some of them can be discarded during query transformation.
3486 : * The flattening we're doing here is an optional optimization, too. (If
3487 : * you are unpersuaded and want to change this, note that applying
3488 : * adjust_view_column_set to view_perminfo->selectedCols is clearly *not*
3489 : * the right answer, since that neglects base-rel columns used in the
3490 : * view's WHERE quals.)
3491 : *
3492 : * This step needs the modified view targetlist, so we have to do things
3493 : * in this order.
3494 : */
3495 : Assert(bms_is_empty(new_perminfo->insertedCols) &&
3496 : bms_is_empty(new_perminfo->updatedCols));
3497 :
3498 3044 : new_perminfo->selectedCols = base_perminfo->selectedCols;
3499 :
3500 3044 : new_perminfo->insertedCols =
3501 3044 : adjust_view_column_set(view_perminfo->insertedCols, view_targetlist);
3502 :
3503 3044 : new_perminfo->updatedCols =
3504 3044 : adjust_view_column_set(view_perminfo->updatedCols, view_targetlist);
3505 :
3506 : /*
3507 : * Move any security barrier quals from the view RTE onto the new target
3508 : * RTE. Any such quals should now apply to the new target RTE and will
3509 : * not reference the original view RTE in the rewritten query.
3510 : */
3511 3044 : new_rte->securityQuals = view_rte->securityQuals;
3512 3044 : view_rte->securityQuals = NIL;
3513 :
3514 : /*
3515 : * Now update all Vars in the outer query that reference the view to
3516 : * reference the appropriate column of the base relation instead.
3517 : */
3518 : parsetree = (Query *)
3519 3044 : ReplaceVarsFromTargetList((Node *) parsetree,
3520 : parsetree->resultRelation,
3521 : 0,
3522 : view_rte,
3523 : view_targetlist,
3524 : REPLACEVARS_REPORT_ERROR,
3525 : 0,
3526 : NULL);
3527 :
3528 : /*
3529 : * Update all other RTI references in the query that point to the view
3530 : * (for example, parsetree->resultRelation itself) to point to the new
3531 : * base relation instead. Vars will not be affected since none of them
3532 : * reference parsetree->resultRelation any longer.
3533 : */
3534 3044 : ChangeVarNodes((Node *) parsetree,
3535 : parsetree->resultRelation,
3536 : new_rt_index,
3537 : 0);
3538 : Assert(parsetree->resultRelation == new_rt_index);
3539 :
3540 : /*
3541 : * For INSERT/UPDATE we must also update resnos in the targetlist to refer
3542 : * to columns of the base relation, since those indicate the target
3543 : * columns to be affected. Similarly, for MERGE we must update the resnos
3544 : * in the merge action targetlists of any INSERT/UPDATE actions.
3545 : *
3546 : * Note that this destroys the resno ordering of the targetlists, but that
3547 : * will be fixed when we recurse through RewriteQuery, which will invoke
3548 : * rewriteTargetListIU again on the updated targetlists.
3549 : */
3550 3044 : if (parsetree->commandType != CMD_DELETE)
3551 : {
3552 5666 : foreach(lc, parsetree->targetList)
3553 : {
3554 2916 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
3555 : TargetEntry *view_tle;
3556 :
3557 2916 : if (tle->resjunk)
3558 0 : continue;
3559 :
3560 2916 : view_tle = get_tle_by_resno(view_targetlist, tle->resno);
3561 2916 : if (view_tle != NULL && !view_tle->resjunk && IsA(view_tle->expr, Var))
3562 2916 : tle->resno = ((Var *) view_tle->expr)->varattno;
3563 : else
3564 0 : elog(ERROR, "attribute number %d not found in view targetlist",
3565 : tle->resno);
3566 : }
3567 :
3568 6376 : foreach_node(MergeAction, action, parsetree->mergeActionList)
3569 : {
3570 876 : if (action->commandType == CMD_INSERT ||
3571 726 : action->commandType == CMD_UPDATE)
3572 : {
3573 2496 : foreach_node(TargetEntry, tle, action->targetList)
3574 : {
3575 : TargetEntry *view_tle;
3576 :
3577 936 : if (tle->resjunk)
3578 0 : continue;
3579 :
3580 936 : view_tle = get_tle_by_resno(view_targetlist, tle->resno);
3581 936 : if (view_tle != NULL && !view_tle->resjunk && IsA(view_tle->expr, Var))
3582 936 : tle->resno = ((Var *) view_tle->expr)->varattno;
3583 : else
3584 0 : elog(ERROR, "attribute number %d not found in view targetlist",
3585 : tle->resno);
3586 : }
3587 : }
3588 : }
3589 : }
3590 :
3591 : /*
3592 : * For INSERT .. ON CONFLICT .. DO UPDATE, we must also update assorted
3593 : * stuff in the onConflict data structure.
3594 : */
3595 3044 : if (parsetree->onConflict &&
3596 156 : parsetree->onConflict->action == ONCONFLICT_UPDATE)
3597 : {
3598 : Index old_exclRelIndex,
3599 : new_exclRelIndex;
3600 : ParseNamespaceItem *new_exclNSItem;
3601 : RangeTblEntry *new_exclRte;
3602 : List *tmp_tlist;
3603 :
3604 : /*
3605 : * Like the INSERT/UPDATE code above, update the resnos in the
3606 : * auxiliary UPDATE targetlist to refer to columns of the base
3607 : * relation.
3608 : */
3609 288 : foreach(lc, parsetree->onConflict->onConflictSet)
3610 : {
3611 144 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
3612 : TargetEntry *view_tle;
3613 :
3614 144 : if (tle->resjunk)
3615 0 : continue;
3616 :
3617 144 : view_tle = get_tle_by_resno(view_targetlist, tle->resno);
3618 144 : if (view_tle != NULL && !view_tle->resjunk && IsA(view_tle->expr, Var))
3619 144 : tle->resno = ((Var *) view_tle->expr)->varattno;
3620 : else
3621 0 : elog(ERROR, "attribute number %d not found in view targetlist",
3622 : tle->resno);
3623 : }
3624 :
3625 : /*
3626 : * Also, create a new RTE for the EXCLUDED pseudo-relation, using the
3627 : * query's new base rel (which may well have a different column list
3628 : * from the view, hence we need a new column alias list). This should
3629 : * match transformOnConflictClause. In particular, note that the
3630 : * relkind is set to composite to signal that we're not dealing with
3631 : * an actual relation.
3632 : */
3633 144 : old_exclRelIndex = parsetree->onConflict->exclRelIndex;
3634 :
3635 144 : new_exclNSItem = addRangeTableEntryForRelation(make_parsestate(NULL),
3636 : base_rel,
3637 : RowExclusiveLock,
3638 : makeAlias("excluded", NIL),
3639 : false, false);
3640 144 : new_exclRte = new_exclNSItem->p_rte;
3641 144 : new_exclRte->relkind = RELKIND_COMPOSITE_TYPE;
3642 : /* Ignore the RTEPermissionInfo that would've been added. */
3643 144 : new_exclRte->perminfoindex = 0;
3644 :
3645 144 : parsetree->rtable = lappend(parsetree->rtable, new_exclRte);
3646 288 : new_exclRelIndex = parsetree->onConflict->exclRelIndex =
3647 144 : list_length(parsetree->rtable);
3648 :
3649 : /*
3650 : * Replace the targetlist for the EXCLUDED pseudo-relation with a new
3651 : * one, representing the columns from the new base relation.
3652 : */
3653 288 : parsetree->onConflict->exclRelTlist =
3654 144 : BuildOnConflictExcludedTargetlist(base_rel, new_exclRelIndex);
3655 :
3656 : /*
3657 : * Update all Vars in the ON CONFLICT clause that refer to the old
3658 : * EXCLUDED pseudo-relation. We want to use the column mappings
3659 : * defined in the view targetlist, but we need the outputs to refer to
3660 : * the new EXCLUDED pseudo-relation rather than the new target RTE.
3661 : * Also notice that "EXCLUDED.*" will be expanded using the view's
3662 : * rowtype, which seems correct.
3663 : */
3664 144 : tmp_tlist = copyObject(view_targetlist);
3665 :
3666 144 : ChangeVarNodes((Node *) tmp_tlist, new_rt_index,
3667 : new_exclRelIndex, 0);
3668 :
3669 144 : parsetree->onConflict = (OnConflictExpr *)
3670 144 : ReplaceVarsFromTargetList((Node *) parsetree->onConflict,
3671 : old_exclRelIndex,
3672 : 0,
3673 : view_rte,
3674 : tmp_tlist,
3675 : REPLACEVARS_REPORT_ERROR,
3676 : 0,
3677 : &parsetree->hasSubLinks);
3678 : }
3679 :
3680 : /*
3681 : * For UPDATE/DELETE/MERGE, pull up any WHERE quals from the view. We
3682 : * know that any Vars in the quals must reference the one base relation,
3683 : * so we need only adjust their varnos to reference the new target (just
3684 : * the same as we did with the view targetlist).
3685 : *
3686 : * If it's a security-barrier view, its WHERE quals must be applied before
3687 : * quals from the outer query, so we attach them to the RTE as security
3688 : * barrier quals rather than adding them to the main WHERE clause.
3689 : *
3690 : * For INSERT, the view's quals can be ignored in the main query.
3691 : */
3692 3044 : if (parsetree->commandType != CMD_INSERT &&
3693 2000 : viewquery->jointree->quals != NULL)
3694 : {
3695 662 : Node *viewqual = (Node *) viewquery->jointree->quals;
3696 :
3697 : /*
3698 : * Even though we copied viewquery already at the top of this
3699 : * function, we must duplicate the viewqual again here, because we may
3700 : * need to use the quals again below for a WithCheckOption clause.
3701 : */
3702 662 : viewqual = copyObject(viewqual);
3703 :
3704 662 : ChangeVarNodes(viewqual, base_rt_index, new_rt_index, 0);
3705 :
3706 662 : if (RelationIsSecurityView(view))
3707 : {
3708 : /*
3709 : * The view's quals go in front of existing barrier quals: those
3710 : * would have come from an outer level of security-barrier view,
3711 : * and so must get evaluated later.
3712 : *
3713 : * Note: the parsetree has been mutated, so the new_rte pointer is
3714 : * stale and needs to be re-computed.
3715 : */
3716 234 : new_rte = rt_fetch(new_rt_index, parsetree->rtable);
3717 234 : new_rte->securityQuals = lcons(viewqual, new_rte->securityQuals);
3718 :
3719 : /*
3720 : * Do not set parsetree->hasRowSecurity, because these aren't RLS
3721 : * conditions (they aren't affected by enabling/disabling RLS).
3722 : */
3723 :
3724 : /*
3725 : * Make sure that the query is marked correctly if the added qual
3726 : * has sublinks.
3727 : */
3728 234 : if (!parsetree->hasSubLinks)
3729 210 : parsetree->hasSubLinks = checkExprHasSubLink(viewqual);
3730 : }
3731 : else
3732 428 : AddQual(parsetree, (Node *) viewqual);
3733 : }
3734 :
3735 : /*
3736 : * For INSERT/UPDATE (or MERGE containing INSERT/UPDATE), if the view has
3737 : * the WITH CHECK OPTION, or any parent view specified WITH CASCADED CHECK
3738 : * OPTION, add the quals from the view to the query's withCheckOptions
3739 : * list.
3740 : */
3741 3044 : if (insert_or_update)
3742 : {
3743 2696 : bool has_wco = RelationHasCheckOption(view);
3744 2696 : bool cascaded = RelationHasCascadedCheckOption(view);
3745 :
3746 : /*
3747 : * If the parent view has a cascaded check option, treat this view as
3748 : * if it also had a cascaded check option.
3749 : *
3750 : * New WithCheckOptions are added to the start of the list, so if
3751 : * there is a cascaded check option, it will be the first item in the
3752 : * list.
3753 : */
3754 2696 : if (parsetree->withCheckOptions != NIL)
3755 : {
3756 114 : WithCheckOption *parent_wco =
3757 114 : (WithCheckOption *) linitial(parsetree->withCheckOptions);
3758 :
3759 114 : if (parent_wco->cascaded)
3760 : {
3761 90 : has_wco = true;
3762 90 : cascaded = true;
3763 : }
3764 : }
3765 :
3766 : /*
3767 : * Add the new WithCheckOption to the start of the list, so that
3768 : * checks on inner views are run before checks on outer views, as
3769 : * required by the SQL standard.
3770 : *
3771 : * If the new check is CASCADED, we need to add it even if this view
3772 : * has no quals, since there may be quals on child views. A LOCAL
3773 : * check can be omitted if this view has no quals.
3774 : */
3775 2696 : if (has_wco && (cascaded || viewquery->jointree->quals != NULL))
3776 : {
3777 : WithCheckOption *wco;
3778 :
3779 626 : wco = makeNode(WithCheckOption);
3780 626 : wco->kind = WCO_VIEW_CHECK;
3781 626 : wco->relname = pstrdup(RelationGetRelationName(view));
3782 626 : wco->polname = NULL;
3783 626 : wco->qual = NULL;
3784 626 : wco->cascaded = cascaded;
3785 :
3786 626 : parsetree->withCheckOptions = lcons(wco,
3787 : parsetree->withCheckOptions);
3788 :
3789 626 : if (viewquery->jointree->quals != NULL)
3790 : {
3791 566 : wco->qual = (Node *) viewquery->jointree->quals;
3792 566 : ChangeVarNodes(wco->qual, base_rt_index, new_rt_index, 0);
3793 :
3794 : /*
3795 : * For INSERT, make sure that the query is marked correctly if
3796 : * the added qual has sublinks. This can be skipped for
3797 : * UPDATE/MERGE, since the same qual will have already been
3798 : * added above, and the check will already have been done.
3799 : */
3800 566 : if (!parsetree->hasSubLinks &&
3801 470 : parsetree->commandType == CMD_INSERT)
3802 312 : parsetree->hasSubLinks = checkExprHasSubLink(wco->qual);
3803 : }
3804 : }
3805 : }
3806 :
3807 3044 : table_close(base_rel, NoLock);
3808 :
3809 3044 : return parsetree;
3810 : }
3811 :
3812 :
3813 : /*
3814 : * RewriteQuery -
3815 : * rewrites the query and apply the rules again on the queries rewritten
3816 : *
3817 : * rewrite_events is a list of open query-rewrite actions, so we can detect
3818 : * infinite recursion.
3819 : *
3820 : * orig_rt_length is the length of the originating query's rtable, for product
3821 : * queries created by fireRules(), and 0 otherwise. This is used to skip any
3822 : * already-processed VALUES RTEs from the original query.
3823 : */
3824 : static List *
3825 434372 : RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
3826 : {
3827 434372 : CmdType event = parsetree->commandType;
3828 434372 : bool instead = false;
3829 434372 : bool returning = false;
3830 434372 : bool updatableview = false;
3831 434372 : Query *qual_product = NULL;
3832 434372 : List *rewritten = NIL;
3833 : ListCell *lc1;
3834 :
3835 : /*
3836 : * First, recursively process any insert/update/delete/merge statements in
3837 : * WITH clauses. (We have to do this first because the WITH clauses may
3838 : * get copied into rule actions below.)
3839 : */
3840 437386 : foreach(lc1, parsetree->cteList)
3841 : {
3842 3044 : CommonTableExpr *cte = lfirst_node(CommonTableExpr, lc1);
3843 3044 : Query *ctequery = castNode(Query, cte->ctequery);
3844 : List *newstuff;
3845 :
3846 3044 : if (ctequery->commandType == CMD_SELECT)
3847 2726 : continue;
3848 :
3849 318 : newstuff = RewriteQuery(ctequery, rewrite_events, 0);
3850 :
3851 : /*
3852 : * Currently we can only handle unconditional, single-statement DO
3853 : * INSTEAD rules correctly; we have to get exactly one non-utility
3854 : * Query out of the rewrite operation to stuff back into the CTE node.
3855 : */
3856 318 : if (list_length(newstuff) == 1)
3857 : {
3858 : /* Must check it's not a utility command */
3859 294 : ctequery = linitial_node(Query, newstuff);
3860 294 : if (!(ctequery->commandType == CMD_SELECT ||
3861 294 : ctequery->commandType == CMD_UPDATE ||
3862 228 : ctequery->commandType == CMD_INSERT ||
3863 72 : ctequery->commandType == CMD_DELETE ||
3864 18 : ctequery->commandType == CMD_MERGE))
3865 : {
3866 : /*
3867 : * Currently it could only be NOTIFY; this error message will
3868 : * need work if we ever allow other utility commands in rules.
3869 : */
3870 6 : ereport(ERROR,
3871 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3872 : errmsg("DO INSTEAD NOTIFY rules are not supported for data-modifying statements in WITH")));
3873 : }
3874 : /* WITH queries should never be canSetTag */
3875 : Assert(!ctequery->canSetTag);
3876 : /* Push the single Query back into the CTE node */
3877 288 : cte->ctequery = (Node *) ctequery;
3878 : }
3879 24 : else if (newstuff == NIL)
3880 : {
3881 6 : ereport(ERROR,
3882 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3883 : errmsg("DO INSTEAD NOTHING rules are not supported for data-modifying statements in WITH")));
3884 : }
3885 : else
3886 : {
3887 : ListCell *lc2;
3888 :
3889 : /* examine queries to determine which error message to issue */
3890 42 : foreach(lc2, newstuff)
3891 : {
3892 36 : Query *q = (Query *) lfirst(lc2);
3893 :
3894 36 : if (q->querySource == QSRC_QUAL_INSTEAD_RULE)
3895 6 : ereport(ERROR,
3896 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3897 : errmsg("conditional DO INSTEAD rules are not supported for data-modifying statements in WITH")));
3898 30 : if (q->querySource == QSRC_NON_INSTEAD_RULE)
3899 6 : ereport(ERROR,
3900 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3901 : errmsg("DO ALSO rules are not supported for data-modifying statements in WITH")));
3902 : }
3903 :
3904 6 : ereport(ERROR,
3905 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3906 : errmsg("multi-statement DO INSTEAD rules are not supported for data-modifying statements in WITH")));
3907 : }
3908 : }
3909 :
3910 : /*
3911 : * If the statement is an insert, update, delete, or merge, adjust its
3912 : * targetlist as needed, and then fire INSERT/UPDATE/DELETE rules on it.
3913 : *
3914 : * SELECT rules are handled later when we have all the queries that should
3915 : * get executed. Also, utilities aren't rewritten at all (do we still
3916 : * need that check?)
3917 : */
3918 434342 : if (event != CMD_SELECT && event != CMD_UTILITY)
3919 : {
3920 : int result_relation;
3921 : RangeTblEntry *rt_entry;
3922 : Relation rt_entry_relation;
3923 : List *locks;
3924 : int product_orig_rt_length;
3925 : List *product_queries;
3926 91742 : bool hasUpdate = false;
3927 91742 : int values_rte_index = 0;
3928 91742 : bool defaults_remaining = false;
3929 :
3930 91742 : result_relation = parsetree->resultRelation;
3931 : Assert(result_relation != 0);
3932 91742 : rt_entry = rt_fetch(result_relation, parsetree->rtable);
3933 : Assert(rt_entry->rtekind == RTE_RELATION);
3934 :
3935 : /*
3936 : * We can use NoLock here since either the parser or
3937 : * AcquireRewriteLocks should have locked the rel already.
3938 : */
3939 91742 : rt_entry_relation = table_open(rt_entry->relid, NoLock);
3940 :
3941 : /*
3942 : * Rewrite the targetlist as needed for the command type.
3943 : */
3944 91742 : if (event == CMD_INSERT)
3945 : {
3946 : ListCell *lc2;
3947 70568 : RangeTblEntry *values_rte = NULL;
3948 :
3949 : /*
3950 : * Test if it's a multi-row INSERT ... VALUES (...), (...), ... by
3951 : * looking for a VALUES RTE in the fromlist. For product queries,
3952 : * we must ignore any already-processed VALUES RTEs from the
3953 : * original query. These appear at the start of the rangetable.
3954 : */
3955 81952 : foreach(lc2, parsetree->jointree->fromlist)
3956 : {
3957 11384 : RangeTblRef *rtr = (RangeTblRef *) lfirst(lc2);
3958 :
3959 11384 : if (IsA(rtr, RangeTblRef) && rtr->rtindex > orig_rt_length)
3960 : {
3961 11060 : RangeTblEntry *rte = rt_fetch(rtr->rtindex,
3962 : parsetree->rtable);
3963 :
3964 11060 : if (rte->rtekind == RTE_VALUES)
3965 : {
3966 : /* should not find more than one VALUES RTE */
3967 4426 : if (values_rte != NULL)
3968 0 : elog(ERROR, "more than one VALUES RTE found");
3969 :
3970 4426 : values_rte = rte;
3971 4426 : values_rte_index = rtr->rtindex;
3972 : }
3973 : }
3974 : }
3975 :
3976 70568 : if (values_rte)
3977 : {
3978 4426 : Bitmapset *unused_values_attrnos = NULL;
3979 :
3980 : /* Process the main targetlist ... */
3981 4426 : parsetree->targetList = rewriteTargetListIU(parsetree->targetList,
3982 : parsetree->commandType,
3983 : parsetree->override,
3984 : rt_entry_relation,
3985 : values_rte,
3986 : values_rte_index,
3987 : &unused_values_attrnos);
3988 : /* ... and the VALUES expression lists */
3989 4366 : if (!rewriteValuesRTE(parsetree, values_rte, values_rte_index,
3990 : rt_entry_relation,
3991 : unused_values_attrnos))
3992 60 : defaults_remaining = true;
3993 : }
3994 : else
3995 : {
3996 : /* Process just the main targetlist */
3997 66088 : parsetree->targetList =
3998 66142 : rewriteTargetListIU(parsetree->targetList,
3999 : parsetree->commandType,
4000 : parsetree->override,
4001 : rt_entry_relation,
4002 : NULL, 0, NULL);
4003 : }
4004 :
4005 70454 : if (parsetree->onConflict &&
4006 1610 : parsetree->onConflict->action == ONCONFLICT_UPDATE)
4007 : {
4008 1276 : parsetree->onConflict->onConflictSet =
4009 1276 : rewriteTargetListIU(parsetree->onConflict->onConflictSet,
4010 : CMD_UPDATE,
4011 : parsetree->override,
4012 : rt_entry_relation,
4013 : NULL, 0, NULL);
4014 : }
4015 : }
4016 21174 : else if (event == CMD_UPDATE)
4017 : {
4018 : Assert(parsetree->override == OVERRIDING_NOT_SET);
4019 14052 : parsetree->targetList =
4020 14076 : rewriteTargetListIU(parsetree->targetList,
4021 : parsetree->commandType,
4022 : parsetree->override,
4023 : rt_entry_relation,
4024 : NULL, 0, NULL);
4025 : }
4026 7098 : else if (event == CMD_MERGE)
4027 : {
4028 : Assert(parsetree->override == OVERRIDING_NOT_SET);
4029 :
4030 : /*
4031 : * Rewrite each action targetlist separately
4032 : */
4033 5942 : foreach(lc1, parsetree->mergeActionList)
4034 : {
4035 3458 : MergeAction *action = (MergeAction *) lfirst(lc1);
4036 :
4037 3458 : switch (action->commandType)
4038 : {
4039 524 : case CMD_NOTHING:
4040 : case CMD_DELETE: /* Nothing to do here */
4041 524 : break;
4042 2934 : case CMD_UPDATE:
4043 : case CMD_INSERT:
4044 :
4045 : /*
4046 : * MERGE actions do not permit multi-row INSERTs, so
4047 : * there is no VALUES RTE to deal with here.
4048 : */
4049 2928 : action->targetList =
4050 2934 : rewriteTargetListIU(action->targetList,
4051 : action->commandType,
4052 : action->override,
4053 : rt_entry_relation,
4054 : NULL, 0, NULL);
4055 2928 : break;
4056 0 : default:
4057 0 : elog(ERROR, "unrecognized commandType: %d", action->commandType);
4058 : break;
4059 : }
4060 : }
4061 : }
4062 4608 : else if (event == CMD_DELETE)
4063 : {
4064 : /* Nothing to do here */
4065 : }
4066 : else
4067 0 : elog(ERROR, "unrecognized commandType: %d", (int) event);
4068 :
4069 : /*
4070 : * Collect and apply the appropriate rules.
4071 : */
4072 91598 : locks = matchLocks(event, rt_entry_relation,
4073 : result_relation, parsetree, &hasUpdate);
4074 :
4075 91580 : product_orig_rt_length = list_length(parsetree->rtable);
4076 91580 : product_queries = fireRules(parsetree,
4077 : result_relation,
4078 : event,
4079 : locks,
4080 : &instead,
4081 : &returning,
4082 : &qual_product);
4083 :
4084 : /*
4085 : * If we have a VALUES RTE with any remaining untouched DEFAULT items,
4086 : * and we got any product queries, finalize the VALUES RTE for each
4087 : * product query (replacing the remaining DEFAULT items with NULLs).
4088 : * We don't do this for the original query, because we know that it
4089 : * must be an auto-insert on a view, and so should use the base
4090 : * relation's defaults for any remaining DEFAULT items.
4091 : */
4092 91574 : if (defaults_remaining && product_queries != NIL)
4093 : {
4094 : ListCell *n;
4095 :
4096 : /*
4097 : * Each product query has its own copy of the VALUES RTE at the
4098 : * same index in the rangetable, so we must finalize each one.
4099 : *
4100 : * Note that if the product query is an INSERT ... SELECT, then
4101 : * the VALUES RTE will be at the same index in the SELECT part of
4102 : * the product query rather than the top-level product query
4103 : * itself.
4104 : */
4105 48 : foreach(n, product_queries)
4106 : {
4107 24 : Query *pt = (Query *) lfirst(n);
4108 : RangeTblEntry *values_rte;
4109 :
4110 24 : if (pt->commandType == CMD_INSERT &&
4111 48 : pt->jointree && IsA(pt->jointree, FromExpr) &&
4112 24 : list_length(pt->jointree->fromlist) == 1)
4113 : {
4114 24 : Node *jtnode = (Node *) linitial(pt->jointree->fromlist);
4115 :
4116 24 : if (IsA(jtnode, RangeTblRef))
4117 : {
4118 24 : int rtindex = ((RangeTblRef *) jtnode)->rtindex;
4119 24 : RangeTblEntry *src_rte = rt_fetch(rtindex, pt->rtable);
4120 :
4121 24 : if (src_rte->rtekind == RTE_SUBQUERY &&
4122 6 : src_rte->subquery &&
4123 6 : IsA(src_rte->subquery, Query) &&
4124 6 : src_rte->subquery->commandType == CMD_SELECT)
4125 6 : pt = src_rte->subquery;
4126 : }
4127 : }
4128 :
4129 24 : values_rte = rt_fetch(values_rte_index, pt->rtable);
4130 24 : if (values_rte->rtekind != RTE_VALUES)
4131 0 : elog(ERROR, "failed to find VALUES RTE in product query");
4132 :
4133 24 : rewriteValuesRTEToNulls(pt, values_rte);
4134 : }
4135 : }
4136 :
4137 : /*
4138 : * If there was no unqualified INSTEAD rule, and the target relation
4139 : * is a view without any INSTEAD OF triggers, see if the view can be
4140 : * automatically updated. If so, we perform the necessary query
4141 : * transformation here and add the resulting query to the
4142 : * product_queries list, so that it gets recursively rewritten if
4143 : * necessary. For MERGE, the view must be automatically updatable if
4144 : * any of the merge actions lack a corresponding INSTEAD OF trigger.
4145 : *
4146 : * If the view cannot be automatically updated, we throw an error here
4147 : * which is OK since the query would fail at runtime anyway. Throwing
4148 : * the error here is preferable to the executor check since we have
4149 : * more detailed information available about why the view isn't
4150 : * updatable.
4151 : */
4152 91574 : if (!instead &&
4153 90920 : rt_entry_relation->rd_rel->relkind == RELKIND_VIEW &&
4154 3692 : !view_has_instead_trigger(rt_entry_relation, event,
4155 : parsetree->mergeActionList))
4156 : {
4157 : /*
4158 : * If there were any qualified INSTEAD rules, don't allow the view
4159 : * to be automatically updated (an unqualified INSTEAD rule or
4160 : * INSTEAD OF trigger is required).
4161 : */
4162 3320 : if (qual_product != NULL)
4163 18 : error_view_not_updatable(rt_entry_relation,
4164 : parsetree->commandType,
4165 : parsetree->mergeActionList,
4166 : gettext_noop("Views with conditional DO INSTEAD rules are not automatically updatable."));
4167 :
4168 : /*
4169 : * Attempt to rewrite the query to automatically update the view.
4170 : * This throws an error if the view can't be automatically
4171 : * updated.
4172 : */
4173 3302 : parsetree = rewriteTargetView(parsetree, rt_entry_relation);
4174 :
4175 : /*
4176 : * At this point product_queries contains any DO ALSO rule
4177 : * actions. Add the rewritten query before or after those. This
4178 : * must match the handling the original query would have gotten
4179 : * below, if we allowed it to be included again.
4180 : */
4181 3044 : if (parsetree->commandType == CMD_INSERT)
4182 1044 : product_queries = lcons(parsetree, product_queries);
4183 : else
4184 2000 : product_queries = lappend(product_queries, parsetree);
4185 :
4186 : /*
4187 : * Set the "instead" flag, as if there had been an unqualified
4188 : * INSTEAD, to prevent the original query from being included a
4189 : * second time below. The transformation will have rewritten any
4190 : * RETURNING list, so we can also set "returning" to forestall
4191 : * throwing an error below.
4192 : */
4193 3044 : instead = true;
4194 3044 : returning = true;
4195 3044 : updatableview = true;
4196 : }
4197 :
4198 : /*
4199 : * If we got any product queries, recursively rewrite them --- but
4200 : * first check for recursion!
4201 : */
4202 91298 : if (product_queries != NIL)
4203 : {
4204 : ListCell *n;
4205 : rewrite_event *rev;
4206 :
4207 5060 : foreach(n, rewrite_events)
4208 : {
4209 930 : rev = (rewrite_event *) lfirst(n);
4210 930 : if (rev->relation == RelationGetRelid(rt_entry_relation) &&
4211 0 : rev->event == event)
4212 0 : ereport(ERROR,
4213 : (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
4214 : errmsg("infinite recursion detected in rules for relation \"%s\"",
4215 : RelationGetRelationName(rt_entry_relation))));
4216 : }
4217 :
4218 4130 : rev = (rewrite_event *) palloc(sizeof(rewrite_event));
4219 4130 : rev->relation = RelationGetRelid(rt_entry_relation);
4220 4130 : rev->event = event;
4221 4130 : rewrite_events = lappend(rewrite_events, rev);
4222 :
4223 8386 : foreach(n, product_queries)
4224 : {
4225 4364 : Query *pt = (Query *) lfirst(n);
4226 : List *newstuff;
4227 :
4228 : /*
4229 : * For an updatable view, pt might be the rewritten version of
4230 : * the original query, in which case we pass on orig_rt_length
4231 : * to finish processing any VALUES RTE it contained.
4232 : *
4233 : * Otherwise, we have a product query created by fireRules().
4234 : * Any VALUES RTEs from the original query have been fully
4235 : * processed, and must be skipped when we recurse.
4236 : */
4237 4364 : newstuff = RewriteQuery(pt, rewrite_events,
4238 : pt == parsetree ?
4239 : orig_rt_length :
4240 : product_orig_rt_length);
4241 4256 : rewritten = list_concat(rewritten, newstuff);
4242 : }
4243 :
4244 4022 : rewrite_events = list_delete_last(rewrite_events);
4245 : }
4246 :
4247 : /*
4248 : * If there is an INSTEAD, and the original query has a RETURNING, we
4249 : * have to have found a RETURNING in the rule(s), else fail. (Because
4250 : * DefineQueryRewrite only allows RETURNING in unconditional INSTEAD
4251 : * rules, there's no need to worry whether the substituted RETURNING
4252 : * will actually be executed --- it must be.)
4253 : */
4254 91190 : if ((instead || qual_product != NULL) &&
4255 3902 : parsetree->returningList &&
4256 234 : !returning)
4257 : {
4258 6 : switch (event)
4259 : {
4260 6 : case CMD_INSERT:
4261 6 : ereport(ERROR,
4262 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4263 : errmsg("cannot perform INSERT RETURNING on relation \"%s\"",
4264 : RelationGetRelationName(rt_entry_relation)),
4265 : errhint("You need an unconditional ON INSERT DO INSTEAD rule with a RETURNING clause.")));
4266 : break;
4267 0 : case CMD_UPDATE:
4268 0 : ereport(ERROR,
4269 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4270 : errmsg("cannot perform UPDATE RETURNING on relation \"%s\"",
4271 : RelationGetRelationName(rt_entry_relation)),
4272 : errhint("You need an unconditional ON UPDATE DO INSTEAD rule with a RETURNING clause.")));
4273 : break;
4274 0 : case CMD_DELETE:
4275 0 : ereport(ERROR,
4276 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4277 : errmsg("cannot perform DELETE RETURNING on relation \"%s\"",
4278 : RelationGetRelationName(rt_entry_relation)),
4279 : errhint("You need an unconditional ON DELETE DO INSTEAD rule with a RETURNING clause.")));
4280 : break;
4281 0 : default:
4282 0 : elog(ERROR, "unrecognized commandType: %d",
4283 : (int) event);
4284 : break;
4285 : }
4286 91184 : }
4287 :
4288 : /*
4289 : * Updatable views are supported by ON CONFLICT, so don't prevent that
4290 : * case from proceeding
4291 : */
4292 91184 : if (parsetree->onConflict &&
4293 1430 : (product_queries != NIL || hasUpdate) &&
4294 168 : !updatableview)
4295 12 : ereport(ERROR,
4296 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4297 : errmsg("INSERT with ON CONFLICT clause cannot be used with table that has INSERT or UPDATE rules")));
4298 :
4299 91172 : table_close(rt_entry_relation, NoLock);
4300 : }
4301 :
4302 : /*
4303 : * For INSERTs, the original query is done first; for UPDATE/DELETE, it is
4304 : * done last. This is needed because update and delete rule actions might
4305 : * not do anything if they are invoked after the update or delete is
4306 : * performed. The command counter increment between the query executions
4307 : * makes the deleted (and maybe the updated) tuples disappear so the scans
4308 : * for them in the rule actions cannot find them.
4309 : *
4310 : * If we found any unqualified INSTEAD, the original query is not done at
4311 : * all, in any form. Otherwise, we add the modified form if qualified
4312 : * INSTEADs were found, else the unmodified form.
4313 : */
4314 433772 : if (!instead)
4315 : {
4316 430200 : if (parsetree->commandType == CMD_INSERT)
4317 : {
4318 68942 : if (qual_product != NULL)
4319 294 : rewritten = lcons(qual_product, rewritten);
4320 : else
4321 68648 : rewritten = lcons(parsetree, rewritten);
4322 : }
4323 : else
4324 : {
4325 361258 : if (qual_product != NULL)
4326 18 : rewritten = lappend(rewritten, qual_product);
4327 : else
4328 361240 : rewritten = lappend(rewritten, parsetree);
4329 : }
4330 : }
4331 :
4332 : /*
4333 : * If the original query has a CTE list, and we generated more than one
4334 : * non-utility result query, we have to fail because we'll have copied the
4335 : * CTE list into each result query. That would break the expectation of
4336 : * single evaluation of CTEs. This could possibly be fixed by
4337 : * restructuring so that a CTE list can be shared across multiple Query
4338 : * and PlannableStatement nodes.
4339 : */
4340 433772 : if (parsetree->cteList != NIL)
4341 : {
4342 2040 : int qcount = 0;
4343 :
4344 4080 : foreach(lc1, rewritten)
4345 : {
4346 2040 : Query *q = (Query *) lfirst(lc1);
4347 :
4348 2040 : if (q->commandType != CMD_UTILITY)
4349 2040 : qcount++;
4350 : }
4351 2040 : if (qcount > 1)
4352 0 : ereport(ERROR,
4353 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4354 : errmsg("WITH cannot be used in a query that is rewritten by rules into multiple queries")));
4355 : }
4356 :
4357 433772 : return rewritten;
4358 : }
4359 :
4360 :
4361 : /*
4362 : * QueryRewrite -
4363 : * Primary entry point to the query rewriter.
4364 : * Rewrite one query via query rewrite system, possibly returning 0
4365 : * or many queries.
4366 : *
4367 : * NOTE: the parsetree must either have come straight from the parser,
4368 : * or have been scanned by AcquireRewriteLocks to acquire suitable locks.
4369 : */
4370 : List *
4371 429690 : QueryRewrite(Query *parsetree)
4372 : {
4373 429690 : uint64 input_query_id = parsetree->queryId;
4374 : List *querylist;
4375 : List *results;
4376 : ListCell *l;
4377 : CmdType origCmdType;
4378 : bool foundOriginalQuery;
4379 : Query *lastInstead;
4380 :
4381 : /*
4382 : * This function is only applied to top-level original queries
4383 : */
4384 : Assert(parsetree->querySource == QSRC_ORIGINAL);
4385 : Assert(parsetree->canSetTag);
4386 :
4387 : /*
4388 : * Step 1
4389 : *
4390 : * Apply all non-SELECT rules possibly getting 0 or many queries
4391 : */
4392 429690 : querylist = RewriteQuery(parsetree, NIL, 0);
4393 :
4394 : /*
4395 : * Step 2
4396 : *
4397 : * Apply all the RIR rules on each query
4398 : *
4399 : * This is also a handy place to mark each query with the original queryId
4400 : */
4401 429198 : results = NIL;
4402 858954 : foreach(l, querylist)
4403 : {
4404 429852 : Query *query = (Query *) lfirst(l);
4405 :
4406 429852 : query = fireRIRrules(query, NIL);
4407 :
4408 429756 : query->queryId = input_query_id;
4409 :
4410 429756 : results = lappend(results, query);
4411 : }
4412 :
4413 : /*
4414 : * Step 3
4415 : *
4416 : * Determine which, if any, of the resulting queries is supposed to set
4417 : * the command-result tag; and update the canSetTag fields accordingly.
4418 : *
4419 : * If the original query is still in the list, it sets the command tag.
4420 : * Otherwise, the last INSTEAD query of the same kind as the original is
4421 : * allowed to set the tag. (Note these rules can leave us with no query
4422 : * setting the tag. The tcop code has to cope with this by setting up a
4423 : * default tag based on the original un-rewritten query.)
4424 : *
4425 : * The Asserts verify that at most one query in the result list is marked
4426 : * canSetTag. If we aren't checking asserts, we can fall out of the loop
4427 : * as soon as we find the original query.
4428 : */
4429 429102 : origCmdType = parsetree->commandType;
4430 429102 : foundOriginalQuery = false;
4431 429102 : lastInstead = NULL;
4432 :
4433 429906 : foreach(l, results)
4434 : {
4435 429300 : Query *query = (Query *) lfirst(l);
4436 :
4437 429300 : if (query->querySource == QSRC_ORIGINAL)
4438 : {
4439 : Assert(query->canSetTag);
4440 : Assert(!foundOriginalQuery);
4441 428496 : foundOriginalQuery = true;
4442 : #ifndef USE_ASSERT_CHECKING
4443 428496 : break;
4444 : #endif
4445 : }
4446 : else
4447 : {
4448 : Assert(!query->canSetTag);
4449 804 : if (query->commandType == origCmdType &&
4450 606 : (query->querySource == QSRC_INSTEAD_RULE ||
4451 108 : query->querySource == QSRC_QUAL_INSTEAD_RULE))
4452 546 : lastInstead = query;
4453 : }
4454 : }
4455 :
4456 429102 : if (!foundOriginalQuery && lastInstead != NULL)
4457 522 : lastInstead->canSetTag = true;
4458 :
4459 429102 : return results;
4460 : }
|