Age Owner TLA Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * rewriteHandler.c
4 : * Primary module of query rewriter.
5 : *
6 : * Portions Copyright (c) 1996-2023, 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/pg_type.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, RuleLock *rulelocks,
90 : int varno, Query *parsetree, bool *hasUpdate);
91 : static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
92 : static bool view_has_instead_trigger(Relation view, CmdType event);
93 : static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
94 :
95 :
96 : /*
97 : * AcquireRewriteLocks -
98 : * Acquire suitable locks on all the relations mentioned in the Query.
99 : * These locks will ensure that the relation schemas don't change under us
100 : * while we are rewriting, planning, and executing the query.
101 : *
102 : * Caution: this may modify the querytree, therefore caller should usually
103 : * have done a copyObject() to make a writable copy of the querytree in the
104 : * current memory context.
105 : *
106 : * forExecute indicates that the query is about to be executed. If so,
107 : * we'll acquire the lock modes specified in the RTE rellockmode fields.
108 : * If forExecute is false, AccessShareLock is acquired on all relations.
109 : * This case is suitable for ruleutils.c, for example, where we only need
110 : * schema stability and we don't intend to actually modify any relations.
111 : *
112 : * forUpdatePushedDown indicates that a pushed-down FOR [KEY] UPDATE/SHARE
113 : * applies to the current subquery, requiring all rels to be opened with at
114 : * least RowShareLock. This should always be false at the top of the
115 : * recursion. When it is true, we adjust RTE rellockmode fields to reflect
116 : * the higher lock level. This flag is ignored if forExecute is false.
117 : *
118 : * A secondary purpose of this routine is to fix up JOIN RTE references to
119 : * dropped columns (see details below). Such RTEs are modified in-place.
120 : *
121 : * This processing can, and for efficiency's sake should, be skipped when the
122 : * querytree has just been built by the parser: parse analysis already got
123 : * all the same locks we'd get here, and the parser will have omitted dropped
124 : * columns from JOINs to begin with. But we must do this whenever we are
125 : * dealing with a querytree produced earlier than the current command.
126 : *
127 : * About JOINs and dropped columns: although the parser never includes an
128 : * already-dropped column in a JOIN RTE's alias var list, it is possible for
129 : * such a list in a stored rule to include references to dropped columns.
130 : * (If the column is not explicitly referenced anywhere else in the query,
131 : * the dependency mechanism won't consider it used by the rule and so won't
132 : * prevent the column drop.) To support get_rte_attribute_is_dropped(), we
133 : * replace join alias vars that reference dropped columns with null pointers.
134 : *
135 : * (In PostgreSQL 8.0, we did not do this processing but instead had
136 : * get_rte_attribute_is_dropped() recurse to detect dropped columns in joins.
137 : * That approach had horrible performance unfortunately; in particular
138 : * construction of a nested join was O(N^2) in the nesting depth.)
139 : */
140 : void
3321 tgl 141 CBC 32247 : AcquireRewriteLocks(Query *parsetree,
142 : bool forExecute,
143 : bool forUpdatePushedDown)
144 : {
145 : ListCell *l;
146 : int rt_index;
147 : acquireLocksOnSubLinks_context context;
148 :
149 32247 : context.for_execute = forExecute;
150 :
151 : /*
152 : * First, process RTEs of the current query level.
153 : */
6519 154 32247 : rt_index = 0;
155 64760 : foreach(l, parsetree->rtable)
156 : {
157 32513 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
158 : Relation rel;
159 : LOCKMODE lockmode;
160 : List *newaliasvars;
161 : Index curinputvarno;
162 : RangeTblEntry *curinputrte;
163 : ListCell *ll;
164 :
165 32513 : ++rt_index;
166 32513 : switch (rte->rtekind)
167 : {
168 20928 : case RTE_RELATION:
169 :
170 : /*
171 : * Grab the appropriate lock type for the relation, and do not
172 : * release it until end of transaction. This protects the
173 : * rewriter, planner, and executor against schema changes
174 : * mid-query.
175 : *
176 : * If forExecute is false, ignore rellockmode and just use
177 : * AccessShareLock.
178 : */
3321 179 20928 : if (!forExecute)
180 3178 : lockmode = AccessShareLock;
1652 181 17750 : else if (forUpdatePushedDown)
182 : {
183 : /* Upgrade RTE's lock mode to reflect pushed-down lock */
184 48 : if (rte->rellockmode == AccessShareLock)
185 48 : rte->rellockmode = RowShareLock;
1650 186 48 : lockmode = rte->rellockmode;
187 : }
188 : else
189 17702 : lockmode = rte->rellockmode;
190 :
1539 andres 191 20928 : rel = table_open(rte->relid, lockmode);
192 :
193 : /*
194 : * While we have the relation open, update the RTE's relkind,
195 : * just in case it changed since this rule was made.
196 : */
4429 tgl 197 20928 : rte->relkind = rel->rd_rel->relkind;
198 :
1539 andres 199 20928 : table_close(rel, NoLock);
6519 tgl 200 20928 : break;
201 :
202 6168 : case RTE_JOIN:
203 :
204 : /*
205 : * Scan the join's alias var list to see if any columns have
206 : * been dropped, and if so replace those Vars with null
207 : * pointers.
208 : *
209 : * Since a join has only two inputs, we can expect to see
210 : * multiple references to the same input RTE; optimize away
211 : * multiple fetches.
212 : */
213 6168 : newaliasvars = NIL;
6518 214 6168 : curinputvarno = 0;
215 6168 : curinputrte = NULL;
6519 216 229520 : foreach(ll, rte->joinaliasvars)
217 : {
3547 218 223352 : Var *aliasitem = (Var *) lfirst(ll);
219 223352 : Var *aliasvar = aliasitem;
220 :
221 : /* Look through any implicit coercion */
222 223352 : aliasvar = (Var *) strip_implicit_coercions((Node *) aliasvar);
223 :
224 : /*
225 : * If the list item isn't a simple Var, then it must
226 : * represent a merged column, ie a USING column, and so it
227 : * couldn't possibly be dropped, since it's referenced in
228 : * the join clause. (Conceivably it could also be a null
229 : * pointer already? But that's OK too.)
230 : */
231 223352 : if (aliasvar && IsA(aliasvar, Var))
232 : {
233 : /*
234 : * The elements of an alias list have to refer to
235 : * earlier RTEs of the same rtable, because that's the
236 : * order the planner builds things in. So we already
237 : * processed the referenced RTE, and so it's safe to
238 : * use get_rte_attribute_is_dropped on it. (This might
239 : * not hold after rewriting or planning, but it's OK
240 : * to assume here.)
241 : */
6519 242 223265 : Assert(aliasvar->varlevelsup == 0);
6518 243 223265 : if (aliasvar->varno != curinputvarno)
244 : {
245 16349 : curinputvarno = aliasvar->varno;
246 16349 : if (curinputvarno >= rt_index)
6518 tgl 247 UBC 0 : elog(ERROR, "unexpected varno %d in JOIN RTE %d",
248 : curinputvarno, rt_index);
6518 tgl 249 CBC 16349 : curinputrte = rt_fetch(curinputvarno,
250 : parsetree->rtable);
251 : }
252 223265 : if (get_rte_attribute_is_dropped(curinputrte,
253 223265 : aliasvar->varattno))
254 : {
255 : /* Replace the join alias item with a NULL */
3547 256 3 : aliasitem = NULL;
257 : }
258 : }
259 223352 : newaliasvars = lappend(newaliasvars, aliasitem);
260 : }
6519 261 6168 : rte->joinaliasvars = newaliasvars;
262 6168 : break;
263 :
264 1245 : case RTE_SUBQUERY:
265 :
266 : /*
267 : * The subquery RTE itself is all right, but we have to
268 : * recurse to process the represented subquery.
269 : */
4911 270 1245 : AcquireRewriteLocks(rte->subquery,
271 : forExecute,
272 2490 : (forUpdatePushedDown ||
2118 273 1245 : get_parse_rowmark(parsetree, rt_index) != NULL));
6519 274 1245 : break;
275 :
276 4172 : default:
277 : /* ignore other types of RTEs */
278 4172 : break;
279 : }
280 : }
281 :
282 : /* Recurse into subqueries in WITH */
5300 283 32326 : foreach(l, parsetree->cteList)
284 : {
285 79 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(l);
286 :
3321 287 79 : AcquireRewriteLocks((Query *) cte->ctequery, forExecute, false);
288 : }
289 :
290 : /*
291 : * Recurse into sublink subqueries, too. But we already did the ones in
292 : * the rtable and cteList.
293 : */
6519 294 32247 : if (parsetree->hasSubLinks)
3321 295 1860 : query_tree_walker(parsetree, acquireLocksOnSubLinks, &context,
296 : QTW_IGNORE_RC_SUBQUERIES);
6519 297 32247 : }
298 :
299 : /*
300 : * Walker to find sublink subqueries for AcquireRewriteLocks
301 : */
302 : static bool
3321 303 96203 : acquireLocksOnSubLinks(Node *node, acquireLocksOnSubLinks_context *context)
304 : {
6519 305 96203 : if (node == NULL)
306 26295 : return false;
307 69908 : if (IsA(node, SubLink))
308 : {
309 3903 : SubLink *sub = (SubLink *) node;
310 :
311 : /* Do what we came for */
3321 312 3903 : AcquireRewriteLocks((Query *) sub->subselect,
313 3903 : context->for_execute,
314 : false);
315 : /* Fall through to process lefthand args of SubLink */
316 : }
317 :
318 : /*
319 : * Do NOT recurse into Query nodes, because AcquireRewriteLocks already
320 : * processed subselects of subselects for us.
321 : */
6519 322 69908 : return expression_tree_walker(node, acquireLocksOnSubLinks, context);
323 : }
324 :
325 :
326 : /*
327 : * rewriteRuleAction -
328 : * Rewrite the rule action with appropriate qualifiers (taken from
329 : * the triggering query).
330 : *
331 : * Input arguments:
332 : * parsetree - original query
333 : * rule_action - one action (query) of a rule
334 : * rule_qual - WHERE condition of rule, or NULL if unconditional
335 : * rt_index - RT index of result relation in original query
336 : * event - type of rule event
337 : * Output arguments:
338 : * *returning_flag - set true if we rewrite RETURNING clause in rule_action
339 : * (must be initialized to false)
340 : * Return value:
341 : * rewritten form of rule_action
342 : */
343 : static Query *
7970 344 666 : rewriteRuleAction(Query *parsetree,
345 : Query *rule_action,
346 : Node *rule_qual,
347 : int rt_index,
348 : CmdType event,
349 : bool *returning_flag)
350 : {
351 : int current_varno,
352 : new_varno;
353 : int rt_length;
354 : Query *sub_action;
355 : Query **sub_action_ptr;
356 : acquireLocksOnSubLinks_context context;
357 : ListCell *lc;
358 :
3321 359 666 : context.for_execute = true;
360 :
361 : /*
362 : * Make modifiable copies of rule action and qual (what we're passed are
363 : * the stored versions in the relcache; don't touch 'em!).
364 : */
2222 peter_e 365 666 : rule_action = copyObject(rule_action);
366 666 : rule_qual = copyObject(rule_qual);
367 :
368 : /*
369 : * Acquire necessary locks and fix any deleted JOIN RTE entries.
370 : */
3321 tgl 371 666 : AcquireRewriteLocks(rule_action, true, false);
372 666 : (void) acquireLocksOnSubLinks(rule_qual, &context);
373 :
7970 374 666 : current_varno = rt_index;
6888 neilc 375 666 : rt_length = list_length(parsetree->rtable);
7970 tgl 376 666 : new_varno = PRS2_NEW_VARNO + rt_length;
377 :
378 : /*
379 : * Adjust rule action and qual to offset its varnos, so that we can merge
380 : * its rtable with the main parsetree's rtable.
381 : *
382 : * If the rule action is an INSERT...SELECT, the OLD/NEW rtable entries
383 : * will be in the SELECT part, and we have to modify that rather than the
384 : * top-level INSERT (kluge!).
385 : */
386 666 : sub_action = getInsertSelectQuery(rule_action, &sub_action_ptr);
387 :
8160 388 666 : OffsetVarNodes((Node *) sub_action, rt_length, 0);
7970 389 666 : OffsetVarNodes(rule_qual, rt_length, 0);
390 : /* but references to OLD should point at original rt_index */
8160 391 666 : ChangeVarNodes((Node *) sub_action,
392 : PRS2_OLD_VARNO + rt_length, rt_index, 0);
7970 393 666 : ChangeVarNodes(rule_qual,
394 : PRS2_OLD_VARNO + rt_length, rt_index, 0);
395 :
396 : /*
397 : * Mark any subquery RTEs in the rule action as LATERAL if they contain
398 : * Vars referring to the current query level (references to NEW/OLD).
399 : * Those really are lateral references, but we've historically not
400 : * required users to mark such subqueries with LATERAL explicitly. But
401 : * the planner will complain if such Vars exist in a non-LATERAL subquery,
402 : * so we have to fix things up here.
403 : */
43 dean.a.rasheed 404 2637 : foreach(lc, sub_action->rtable)
405 : {
406 1971 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
407 :
408 1977 : if (rte->rtekind == RTE_SUBQUERY && !rte->lateral &&
409 6 : contain_vars_of_level((Node *) rte->subquery, 1))
410 6 : rte->lateral = true;
411 : }
412 :
413 : /*
414 : * Generate expanded rtable consisting of main parsetree's rtable plus
415 : * rule action's rtable; this becomes the complete rtable for the rule
416 : * action. Some of the entries may be unused after we finish rewriting,
417 : * but we leave them all in place to avoid having to adjust the query's
418 : * varnos. RT entries that are not referenced in the completed jointree
419 : * will be ignored by the planner, so they do not affect query semantics.
420 : *
421 : * Also merge RTEPermissionInfo lists to ensure that all permissions are
422 : * checked correctly.
423 : *
424 : * If the rule is INSTEAD, then the original query won't be executed at
425 : * all, and so its rteperminfos must be preserved so that the executor
426 : * will do the correct permissions checks on the relations referenced in
427 : * it. This allows us to check that the caller has, say, insert-permission
428 : * on a view, when the view is not semantically referenced at all in the
429 : * resulting query.
430 : *
431 : * When a rule is not INSTEAD, the permissions checks done using the
432 : * copied entries will be redundant with those done during execution of
433 : * the original query, but we don't bother to treat that case differently.
434 : *
435 : * NOTE: because planner will destructively alter rtable and rteperminfos,
436 : * we must ensure that rule action's lists are separate and shares no
437 : * substructure with the main query's lists. Hence do a deep copy here
438 : * for both.
439 : */
440 : {
124 alvherre 441 GNC 666 : List *rtable_tail = sub_action->rtable;
442 666 : List *perminfos_tail = sub_action->rteperminfos;
443 :
444 : /*
445 : * RewriteQuery relies on the fact that RT entries from the original
446 : * query appear at the start of the expanded rtable, so we put the
447 : * action's original table at the end of the list.
448 : */
449 666 : sub_action->rtable = copyObject(parsetree->rtable);
450 666 : sub_action->rteperminfos = copyObject(parsetree->rteperminfos);
451 666 : CombineRangeTables(&sub_action->rtable, &sub_action->rteperminfos,
452 : rtable_tail, perminfos_tail);
453 : }
454 :
455 : /*
5310 tgl 456 ECB : * There could have been some SubLinks in parsetree's rtable, in which
457 : * case we'd better mark the sub_action correctly.
458 : */
5310 tgl 459 GIC 666 : if (parsetree->hasSubLinks && !sub_action->hasSubLinks)
460 : {
461 27 : foreach(lc, parsetree->rtable)
462 : {
463 18 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
464 :
465 18 : switch (rte->rtekind)
5310 tgl 466 ECB : {
2815 tgl 467 GIC 15 : case RTE_RELATION:
2815 tgl 468 CBC 15 : sub_action->hasSubLinks =
2815 tgl 469 GIC 15 : checkExprHasSubLink((Node *) rte->tablesample);
2815 tgl 470 CBC 15 : break;
5310 tgl 471 UIC 0 : case RTE_FUNCTION:
5310 tgl 472 LBC 0 : sub_action->hasSubLinks =
3426 tgl 473 UIC 0 : checkExprHasSubLink((Node *) rte->functions);
5310 tgl 474 LBC 0 : break;
2223 alvherre 475 0 : case RTE_TABLEFUNC:
476 0 : sub_action->hasSubLinks =
477 0 : checkExprHasSubLink((Node *) rte->tablefunc);
2223 alvherre 478 UBC 0 : break;
5310 tgl 479 0 : case RTE_VALUES:
480 0 : sub_action->hasSubLinks =
481 0 : checkExprHasSubLink((Node *) rte->values_lists);
482 0 : break;
5310 tgl 483 GBC 3 : default:
5310 tgl 484 EUB : /* other RTE types don't contain bare expressions */
5310 tgl 485 GBC 3 : break;
5310 tgl 486 EUB : }
5310 tgl 487 GBC 18 : if (sub_action->hasSubLinks)
5050 bruce 488 UBC 0 : break; /* no need to keep scanning rtable */
5310 tgl 489 EUB : }
5310 tgl 490 ECB : }
491 :
2341 492 : /*
493 : * Also, we might have absorbed some RTEs with RLS conditions into the
494 : * sub_action. If so, mark it as hasRowSecurity, whether or not those
2341 tgl 495 EUB : * RTEs will be referenced after we finish rewriting. (Note: currently
496 : * this is a no-op because RLS conditions aren't added till later, but it
497 : * seems like good future-proofing to do this anyway.)
498 : */
2341 tgl 499 GIC 666 : sub_action->hasRowSecurity |= parsetree->hasRowSecurity;
500 :
501 : /*
502 : * Each rule action's jointree should be the main parsetree's jointree
503 : * plus that rule's jointree, but usually *without* the original rtindex
504 : * that we're replacing (if present, which it won't be for INSERT). Note
505 : * that if the rule action refers to OLD, its jointree will add a
6385 bruce 506 ECB : * reference to rt_index. If the rule action doesn't refer to OLD, but
507 : * either the rule_qual or the user query quals do, then we need to keep
508 : * the original rtindex in the jointree to provide data for the quals. We
509 : * don't want the original rtindex to be joined twice, however, so avoid
510 : * keeping it if the rule action mentions it.
511 : *
512 : * As above, the action's jointree must not share substructure with the
513 : * main parsetree's.
514 : */
7207 tgl 515 GIC 666 : if (sub_action->commandType != CMD_UTILITY)
516 : {
517 : bool keeporig;
518 : List *newjointree;
519 :
520 654 : Assert(sub_action->jointree != NULL);
8053 bruce 521 654 : keeporig = (!rangeTableEntry_used((Node *) sub_action->jointree,
8053 bruce 522 CBC 1554 : rt_index, 0)) &&
7970 tgl 523 GIC 900 : (rangeTableEntry_used(rule_qual, rt_index, 0) ||
6385 bruce 524 450 : rangeTableEntry_used(parsetree->jointree->quals, rt_index, 0));
8107 tgl 525 654 : newjointree = adjustJoinTreeList(parsetree, !keeporig, rt_index);
7207 526 654 : if (newjointree != NIL)
7207 tgl 527 ECB : {
528 : /*
6385 bruce 529 : * If sub_action is a setop, manipulating its jointree will do no
3260 530 : * good at all, because the jointree is dummy. (Perhaps someday
6385 531 : * we could push the joining and quals down to the member
532 : * statements of the setop?)
7207 tgl 533 : */
7207 tgl 534 GIC 138 : if (sub_action->setOperations != NULL)
7198 tgl 535 UIC 0 : ereport(ERROR,
536 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
537 : errmsg("conditional UNION/INTERSECT/EXCEPT statements are not implemented")));
538 :
7207 tgl 539 GIC 276 : sub_action->jointree->fromlist =
6888 neilc 540 138 : list_concat(newjointree, sub_action->jointree->fromlist);
6346 tgl 541 ECB :
6346 tgl 542 EUB : /*
543 : * There could have been some SubLinks in newjointree, in which
544 : * case we'd better mark the sub_action correctly.
545 : */
6346 tgl 546 CBC 138 : if (parsetree->hasSubLinks && !sub_action->hasSubLinks)
547 3 : sub_action->hasSubLinks =
6346 tgl 548 GIC 3 : checkExprHasSubLink((Node *) newjointree);
549 : }
550 : }
551 :
552 : /*
4322 bruce 553 ECB : * If the original query has any CTEs, copy them into the rule action. But
554 : * we don't need them for a utility action.
4324 tgl 555 : */
4324 tgl 556 GIC 666 : if (parsetree->cteList != NIL && sub_action->commandType != CMD_UTILITY)
557 : {
558 : /*
559 : * Annoying implementation restriction: because CTEs are identified by
560 : * name within a cteList, we can't merge a CTE from the original query
561 : * if it has the same name as any CTE in the rule action.
562 : *
4324 tgl 563 ECB : * This could possibly be fixed by using some sort of internally
564 : * generated ID, instead of names, to link CTE RTEs to their CTEs.
565 : * However, decompiling the results would be quite confusing; note the
566 : * merge of hasRecursive flags below, which could change the apparent
567 : * semantics of such redundantly-named CTEs.
568 : */
4324 tgl 569 GIC 30 : foreach(lc, parsetree->cteList)
570 : {
571 15 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
572 : ListCell *lc2;
573 :
574 15 : foreach(lc2, sub_action->cteList)
575 : {
4324 tgl 576 LBC 0 : CommonTableExpr *cte2 = (CommonTableExpr *) lfirst(lc2);
577 :
578 0 : if (strcmp(cte->ctename, cte2->ctename) == 0)
4324 tgl 579 UIC 0 : ereport(ERROR,
580 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4324 tgl 581 ECB : errmsg("WITH query name \"%s\" appears in both a rule action and the query being rewritten",
582 : cte->ctename)));
4324 tgl 583 EUB : }
584 : }
585 :
586 : /* OK, it's safe to combine the CTE lists */
4324 tgl 587 GIC 15 : sub_action->cteList = list_concat(sub_action->cteList,
588 15 : copyObject(parsetree->cteList));
589 : /* ... and don't forget about the associated flags */
578 590 15 : sub_action->hasRecursive |= parsetree->hasRecursive;
591 15 : sub_action->hasModifyingCTE |= parsetree->hasModifyingCTE;
592 :
593 : /*
578 tgl 594 ECB : * If rule_action is different from sub_action (i.e., the rule action
595 : * is an INSERT...SELECT), then we might have just added some
596 : * data-modifying CTEs that are not at the top query level. This is
597 : * disallowed by the parser and we mustn't generate such trees here
598 : * either, so throw an error.
599 : *
600 : * Conceivably such cases could be supported by attaching the original
601 : * query's CTEs to rule_action not sub_action. But to do that, we'd
602 : * have to increment ctelevelsup in RTEs and SubLinks copied from the
603 : * original query. For now, it doesn't seem worth the trouble.
604 : */
578 tgl 605 GIC 15 : if (sub_action->hasModifyingCTE && rule_action != sub_action)
606 3 : ereport(ERROR,
607 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
608 : errmsg("INSERT ... SELECT rule actions are not supported for queries having data-modifying statements in WITH")));
609 : }
610 :
611 : /*
6385 bruce 612 ECB : * Event Qualification forces copying of parsetree and splitting into two
613 : * queries one w/rule_qual, one w/NOT rule_qual. Also add user query qual
614 : * onto rule action
615 : */
7970 tgl 616 GIC 663 : AddQual(sub_action, rule_qual);
617 :
8160 618 663 : AddQual(sub_action, parsetree->jointree->quals);
619 :
620 : /*
621 : * Rewrite new.attribute with right hand side of target-list entry for
622 : * appropriate field name in insert/update.
8160 tgl 623 ECB : *
624 : * KLUGE ALERT: since ReplaceVarsFromTargetList returns a mutated copy, we
3804 625 : * can't just apply it to sub_action; we have to remember to update the
626 : * sublink inside rule_action, too.
627 : */
6819 tgl 628 GIC 663 : if ((event == CMD_INSERT || event == CMD_UPDATE) &&
629 582 : sub_action->commandType != CMD_UTILITY)
630 : {
631 : sub_action = (Query *)
3804 632 1140 : ReplaceVarsFromTargetList((Node *) sub_action,
633 : new_varno,
634 : 0,
3804 tgl 635 CBC 570 : rt_fetch(new_varno, sub_action->rtable),
3804 tgl 636 ECB : parsetree->targetList,
637 : (event == CMD_UPDATE) ?
638 : REPLACEVARS_CHANGE_VARNO :
639 : REPLACEVARS_SUBSTITUTE_NULL,
640 : current_varno,
641 : NULL);
8160 tgl 642 CBC 570 : if (sub_action_ptr)
8160 tgl 643 GIC 27 : *sub_action_ptr = sub_action;
644 : else
7970 645 543 : rule_action = sub_action;
646 : }
647 :
648 : /*
6031 bruce 649 ECB : * If rule_action has a RETURNING clause, then either throw it away if the
650 : * triggering query has no RETURNING clause, or rewrite it to emit what
651 : * the triggering query's RETURNING clause asks for. Throw an error if
652 : * more than one rule has a RETURNING clause.
653 : */
6063 tgl 654 GIC 663 : if (!parsetree->returningList)
655 603 : rule_action->returningList = NIL;
656 60 : else if (rule_action->returningList)
657 : {
658 54 : if (*returning_flag)
6063 tgl 659 UIC 0 : ereport(ERROR,
660 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2118 tgl 661 ECB : errmsg("cannot have RETURNING lists in multiple rules")));
6063 tgl 662 CBC 54 : *returning_flag = true;
663 54 : rule_action->returningList = (List *)
3804 tgl 664 GIC 54 : ReplaceVarsFromTargetList((Node *) parsetree->returningList,
3804 tgl 665 ECB : parsetree->resultRelation,
3804 tgl 666 EUB : 0,
3804 tgl 667 GIC 54 : rt_fetch(parsetree->resultRelation,
668 : parsetree->rtable),
3804 tgl 669 ECB : rule_action->returningList,
670 : REPLACEVARS_REPORT_ERROR,
671 : 0,
672 : &rule_action->hasSubLinks);
673 :
5310 674 : /*
675 : * There could have been some SubLinks in parsetree's returningList,
676 : * in which case we'd better mark the rule_action correctly.
677 : */
5310 tgl 678 GIC 54 : if (parsetree->hasSubLinks && !rule_action->hasSubLinks)
5310 tgl 679 UIC 0 : rule_action->hasSubLinks =
5050 bruce 680 0 : checkExprHasSubLink((Node *) rule_action->returningList);
681 : }
682 :
7970 tgl 683 GIC 663 : return rule_action;
684 : }
9770 scrappy 685 ECB :
8955 bruce 686 EUB : /*
8107 tgl 687 : * Copy the query's jointree list, and optionally attempt to remove any
688 : * occurrence of the given rt_index as a top-level join item (we do not look
689 : * for it within join items; this is OK because we are only expecting to find
8107 tgl 690 ECB : * it as an UPDATE or DELETE target relation, which will be at the top level
691 : * of the join). Returns modified jointree list --- this is a separate copy
692 : * sharing no nodes with the original.
693 : */
694 : static List *
8107 tgl 695 GIC 654 : adjustJoinTreeList(Query *parsetree, bool removert, int rt_index)
696 : {
7971 697 654 : List *newjointree = copyObject(parsetree->jointree->fromlist);
698 : ListCell *l;
699 :
8107 700 654 : if (removert)
701 : {
6892 neilc 702 CBC 774 : foreach(l, newjointree)
703 : {
704 351 : RangeTblRef *rtr = lfirst(l);
705 :
7418 tgl 706 GIC 351 : if (IsA(rtr, RangeTblRef) &&
7418 tgl 707 CBC 351 : rtr->rtindex == rt_index)
708 : {
899 drowley 709 231 : newjointree = foreach_delete_current(newjointree, l);
8107 tgl 710 GIC 231 : break;
8107 tgl 711 ECB : }
712 : }
9770 scrappy 713 : }
8244 tgl 714 CBC 654 : return newjointree;
715 : }
8994 bruce 716 ECB :
9345 717 :
718 : /*
719 : * rewriteTargetListIU - rewrite INSERT/UPDATE targetlist into standard form
720 : *
7674 tgl 721 : * This has the following responsibilities:
722 : *
723 : * 1. For an INSERT, add tlist entries to compute default values for any
724 : * attributes that have defaults and are not assigned to in the given tlist.
725 : * (We do not insert anything for default-less attributes, however. The
726 : * planner will later insert NULLs for them, but there's no reason to slow
727 : * down rewriter processing with extra tlist nodes.) Also, for both INSERT
728 : * and UPDATE, replace explicit DEFAULT specifications with column default
729 : * expressions.
730 : *
731 : * 2. Merge multiple entries for the same target attribute, or declare error
732 : * if we can't. Multiple entries are only allowed for INSERT/UPDATE of
733 : * portions of an array or record field, for example
734 : * UPDATE table SET foo[2] = 42, foo[4] = 43;
735 : * We can merge such operations into a single assignment op. Essentially,
736 : * the expression we want to produce in this case is like
737 : * foo = array_set_element(array_set_element(foo, 2, 42), 4, 43)
738 : *
739 : * 3. Sort the tlist into standard order: non-junk fields in order by resno,
740 : * then junk fields (these in no particular order).
741 : *
742 : * We must do items 1 and 2 before firing rewrite rules, else rewritten
743 : * references to NEW.foo will produce wrong or incomplete results. Item 3
744 : * is not needed for rewriting, but it is helpful for the planner, and we
745 : * can do it essentially for free while handling the other items.
746 : *
747 : * If values_rte is non-NULL (i.e., we are doing a multi-row INSERT using
748 : * values from a VALUES RTE), we populate *unused_values_attrnos with the
749 : * attribute numbers of any unused columns from the VALUES RTE. This can
750 : * happen for identity and generated columns whose targetlist entries are
751 : * replaced with generated expressions (if INSERT ... OVERRIDING USER VALUE is
752 : * used, or all the values to be inserted are DEFAULT). This information is
753 : * required by rewriteValuesRTE() to handle any DEFAULT items in the unused
754 : * columns. The caller must have initialized *unused_values_attrnos to NULL.
755 : */
756 : static List *
2893 andres 757 GIC 52177 : rewriteTargetListIU(List *targetList,
758 : CmdType commandType,
759 : OverridingKind override,
760 : Relation target_relation,
761 : RangeTblEntry *values_rte,
762 : int values_rte_index,
763 : Bitmapset **unused_values_attrnos)
7674 tgl 764 ECB : {
765 : TargetEntry **new_tles;
7674 tgl 766 GIC 52177 : List *new_tlist = NIL;
6588 767 52177 : List *junk_tlist = NIL;
768 : Form_pg_attribute att_tup;
769 : int attrno,
770 : next_junk_attrno,
771 : numattrs;
772 : ListCell *temp;
868 tgl 773 CBC 52177 : Bitmapset *default_only_cols = NULL;
7674 tgl 774 ECB :
775 : /*
776 : * We process the normal (non-junk) attributes by scanning the input tlist
777 : * once and transferring TLEs into an array, then scanning the array to
778 : * build an output tlist. This avoids O(N^2) behavior for large numbers
779 : * of attributes.
6588 780 : *
781 : * Junk attributes are tossed into a separate list during the same tlist
782 : * scan, then appended to the reconstructed tlist.
783 : */
7674 tgl 784 GIC 52177 : numattrs = RelationGetNumberOfAttributes(target_relation);
6588 785 52177 : new_tles = (TargetEntry **) palloc0(numattrs * sizeof(TargetEntry *));
786 52177 : next_junk_attrno = numattrs + 1;
787 :
2893 andres 788 193284 : foreach(temp, targetList)
789 : {
6588 tgl 790 141116 : TargetEntry *old_tle = (TargetEntry *) lfirst(temp);
7555 tgl 791 ECB :
6577 tgl 792 CBC 141116 : if (!old_tle->resjunk)
6588 tgl 793 ECB : {
794 : /* Normal attr: stash it into new_tles[] */
6577 tgl 795 CBC 141053 : attrno = old_tle->resno;
6588 tgl 796 GIC 141053 : if (attrno < 1 || attrno > numattrs)
6588 tgl 797 LBC 0 : elog(ERROR, "bogus resno %d in targetlist", attrno);
2058 andres 798 GIC 141053 : att_tup = TupleDescAttr(target_relation->rd_att, attrno - 1);
6588 tgl 799 ECB :
800 : /* We can (and must) ignore deleted attributes */
6588 tgl 801 GIC 141053 : if (att_tup->attisdropped)
6588 tgl 802 LBC 0 : continue;
6588 tgl 803 ECB :
6588 tgl 804 EUB : /* Merge with any prior assignment to same attribute */
6588 tgl 805 CBC 141044 : new_tles[attrno - 1] =
6588 tgl 806 GIC 141053 : process_matched_tle(old_tle,
807 141053 : new_tles[attrno - 1],
6588 tgl 808 CBC 141053 : NameStr(att_tup->attname));
6588 tgl 809 EUB : }
810 : else
811 : {
6588 tgl 812 ECB : /*
6385 bruce 813 : * Copy all resjunk tlist entries to junk_tlist, and assign them
814 : * resnos above the last real resno.
6588 tgl 815 : *
816 : * Typical junk entries include ORDER BY or GROUP BY expressions
817 : * (are these actually possible in an INSERT or UPDATE?), system
818 : * attribute references, etc.
819 : */
820 :
821 : /* Get the resno right, but don't copy unnecessarily */
6577 tgl 822 GIC 63 : if (old_tle->resno != next_junk_attrno)
823 : {
6577 tgl 824 UIC 0 : old_tle = flatCopyTargetEntry(old_tle);
825 0 : old_tle->resno = next_junk_attrno;
826 : }
6588 tgl 827 GIC 63 : junk_tlist = lappend(junk_tlist, old_tle);
828 63 : next_junk_attrno++;
7674 tgl 829 ECB : }
830 : }
6588 tgl 831 EUB :
6588 tgl 832 GBC 276029 : for (attrno = 1; attrno <= numattrs; attrno++)
833 : {
6588 tgl 834 CBC 223924 : TargetEntry *new_tle = new_tles[attrno - 1];
2153 bruce 835 ECB : bool apply_default;
836 :
2058 andres 837 GIC 223924 : att_tup = TupleDescAttr(target_relation->rd_att, attrno - 1);
838 :
6588 tgl 839 ECB : /* We can (and must) ignore deleted attributes */
6588 tgl 840 GIC 223924 : if (att_tup->attisdropped)
6588 tgl 841 CBC 448 : continue;
842 :
843 : /*
6385 bruce 844 ECB : * Handle the two cases where we need to insert a default expression:
845 : * it's an INSERT and there's no tlist entry for the column, or the
846 : * tlist entry is a DEFAULT placeholder node.
7220 tgl 847 : */
2194 peter_e 848 CBC 364384 : apply_default = ((new_tle == NULL && commandType == CMD_INSERT) ||
2118 tgl 849 GIC 140908 : (new_tle && new_tle->expr && IsA(new_tle->expr, SetToDefault)));
850 :
2194 peter_e 851 223476 : if (commandType == CMD_INSERT)
852 : {
868 tgl 853 141605 : int values_attrno = 0;
854 :
868 tgl 855 ECB : /* Source attribute number for values that come from a VALUES RTE */
868 tgl 856 CBC 141605 : if (values_rte && new_tle && IsA(new_tle->expr, Var))
857 : {
858 3565 : Var *var = (Var *) new_tle->expr;
859 :
860 3565 : if (var->varno == values_rte_index)
868 tgl 861 GIC 3565 : values_attrno = var->varattno;
862 : }
868 tgl 863 ECB :
864 : /*
865 : * Can only insert DEFAULT into GENERATED ALWAYS identity columns,
866 : * unless either OVERRIDING USER VALUE or OVERRIDING SYSTEM VALUE
867 : * is specified.
868 : */
2194 peter_e 869 GIC 141605 : if (att_tup->attidentity == ATTRIBUTE_IDENTITY_ALWAYS && !apply_default)
870 : {
1104 peter 871 70 : if (override == OVERRIDING_USER_VALUE)
872 21 : apply_default = true;
873 49 : else if (override != OVERRIDING_SYSTEM_VALUE)
874 : {
875 : /*
868 tgl 876 ECB : * If this column's values come from a VALUES RTE, test
877 : * whether it contains only SetToDefault items. Since the
878 : * VALUES list might be quite large, we arrange to only
879 : * scan it once.
880 : */
868 tgl 881 GIC 25 : if (values_attrno != 0)
882 : {
883 13 : if (default_only_cols == NULL)
884 13 : default_only_cols = findDefaultOnlyColumns(values_rte);
885 :
886 13 : if (bms_is_member(values_attrno, default_only_cols))
887 4 : apply_default = true;
868 tgl 888 ECB : }
889 :
868 tgl 890 CBC 25 : if (!apply_default)
891 21 : ereport(ERROR,
892 : (errcode(ERRCODE_GENERATED_ALWAYS),
867 tgl 893 ECB : errmsg("cannot insert a non-DEFAULT value into column \"%s\"",
868 894 : NameStr(att_tup->attname)),
895 : errdetail("Column \"%s\" is an identity column defined as GENERATED ALWAYS.",
896 : NameStr(att_tup->attname)),
897 : errhint("Use OVERRIDING SYSTEM VALUE to override.")));
898 : }
899 : }
900 :
901 : /*
902 : * Although inserting into a GENERATED BY DEFAULT identity column
903 : * is allowed, apply the default if OVERRIDING USER VALUE is
904 : * specified.
905 : */
868 tgl 906 GIC 141584 : if (att_tup->attidentity == ATTRIBUTE_IDENTITY_BY_DEFAULT &&
907 : override == OVERRIDING_USER_VALUE)
2194 peter_e 908 9 : apply_default = true;
909 :
910 : /*
911 : * Can only insert DEFAULT into generated columns, regardless of
912 : * any OVERRIDING clauses.
868 tgl 913 ECB : */
1471 peter 914 GIC 141584 : if (att_tup->attgenerated && !apply_default)
868 tgl 915 ECB : {
916 : /*
917 : * If this column's values come from a VALUES RTE, test
918 : * whether it contains only SetToDefault items, as above.
919 : */
868 tgl 920 GIC 43 : if (values_attrno != 0)
868 tgl 921 ECB : {
868 tgl 922 GIC 28 : if (default_only_cols == NULL)
923 28 : default_only_cols = findDefaultOnlyColumns(values_rte);
924 :
925 28 : if (bms_is_member(values_attrno, default_only_cols))
926 7 : apply_default = true;
868 tgl 927 ECB : }
928 :
868 tgl 929 CBC 43 : if (!apply_default)
930 36 : ereport(ERROR,
931 : (errcode(ERRCODE_GENERATED_ALWAYS),
867 tgl 932 ECB : errmsg("cannot insert a non-DEFAULT value into column \"%s\"",
868 933 : NameStr(att_tup->attname)),
934 : errdetail("Column \"%s\" is a generated column.",
935 : NameStr(att_tup->attname))));
936 : }
937 :
938 : /*
939 : * For an INSERT from a VALUES RTE, return the attribute numbers
940 : * of any VALUES columns that will no longer be used (due to the
941 : * targetlist entry being replaced by a default expression).
942 : */
868 tgl 943 GIC 141548 : if (values_attrno != 0 && apply_default && unused_values_attrnos)
944 23 : *unused_values_attrnos = bms_add_member(*unused_values_attrnos,
945 : values_attrno);
946 : }
947 :
948 : /*
949 : * Updates to identity and generated columns follow the same rules as
868 tgl 950 ECB : * above, except that UPDATE doesn't admit OVERRIDING clauses. Also,
951 : * the source can't be a VALUES RTE, so we needn't consider that.
952 : */
2194 peter_e 953 GIC 223419 : if (commandType == CMD_UPDATE)
954 : {
867 tgl 955 81871 : if (att_tup->attidentity == ATTRIBUTE_IDENTITY_ALWAYS &&
956 6 : new_tle && !apply_default)
2194 peter_e 957 3 : ereport(ERROR,
958 : (errcode(ERRCODE_GENERATED_ALWAYS),
959 : errmsg("column \"%s\" can only be updated to DEFAULT",
867 tgl 960 ECB : NameStr(att_tup->attname)),
961 : errdetail("Column \"%s\" is an identity column defined as GENERATED ALWAYS.",
2194 peter_e 962 : NameStr(att_tup->attname))));
1471 peter 963 :
1471 peter 964 CBC 81868 : if (att_tup->attgenerated && new_tle && !apply_default)
1471 peter 965 GIC 3 : ereport(ERROR,
966 : (errcode(ERRCODE_GENERATED_ALWAYS),
967 : errmsg("column \"%s\" can only be updated to DEFAULT",
968 : NameStr(att_tup->attname)),
969 : errdetail("Column \"%s\" is a generated column.",
970 : NameStr(att_tup->attname))));
2194 peter_e 971 ECB : }
972 :
1471 peter 973 GIC 223413 : if (att_tup->attgenerated)
974 : {
975 : /*
976 : * stored generated column will be fixed in executor
977 : */
978 443 : new_tle = NULL;
979 : }
1471 peter 980 CBC 222970 : else if (apply_default)
981 : {
982 : Node *new_expr;
983 :
1892 peter_e 984 GIC 11684 : new_expr = build_column_default(target_relation, attrno);
7674 tgl 985 ECB :
986 : /*
6385 bruce 987 : * If there is no default (ie, default is effectively NULL), we
988 : * can omit the tlist entry in the INSERT case, since the planner
989 : * can insert a NULL for itself, and there's no point in spending
990 : * any more rewriter cycles on the entry. But in the UPDATE case
991 : * we've got to explicitly set the column to NULL.
992 : */
7220 tgl 993 GIC 11684 : if (!new_expr)
994 : {
995 9025 : if (commandType == CMD_INSERT)
996 9016 : new_tle = NULL;
997 : else
998 : {
999 9 : new_expr = (Node *) makeConst(att_tup->atttypid,
5867 tgl 1000 ECB : -1,
1001 : att_tup->attcollation,
7220 tgl 1002 CBC 9 : att_tup->attlen,
7220 tgl 1003 ECB : (Datum) 0,
1004 : true, /* isnull */
7220 tgl 1005 GIC 9 : att_tup->attbyval);
7220 tgl 1006 ECB : /* this is to catch a NOT NULL domain constraint */
7220 tgl 1007 GIC 9 : new_expr = coerce_to_domain(new_expr,
1008 : InvalidOid, -1,
7220 tgl 1009 ECB : att_tup->atttypid,
1010 : COERCION_IMPLICIT,
1011 : COERCE_IMPLICIT_CAST,
5337 1012 : -1,
1013 : false);
7220 1014 : }
1015 : }
1016 :
7674 tgl 1017 GIC 11684 : if (new_expr)
6577 1018 2668 : new_tle = makeTargetEntry((Expr *) new_expr,
1019 : attrno,
1020 2668 : pstrdup(NameStr(att_tup->attname)),
1021 : false);
1022 : }
1023 :
7674 tgl 1024 CBC 223413 : if (new_tle)
1025 143183 : new_tlist = lappend(new_tlist, new_tle);
1026 : }
7674 tgl 1027 ECB :
6588 tgl 1028 GIC 52105 : pfree(new_tles);
1029 :
2893 andres 1030 52105 : return list_concat(new_tlist, junk_tlist);
7674 tgl 1031 ECB : }
1032 :
1033 :
1034 : /*
1035 : * Convert a matched TLE from the original tlist into a correct new TLE.
1036 : *
1037 : * This routine detects and handles multiple assignments to the same target
1038 : * attribute. (The attribute name is needed only for error messages.)
1039 : */
1040 : static TargetEntry *
7674 tgl 1041 GIC 141053 : process_matched_tle(TargetEntry *src_tle,
1042 : TargetEntry *prior_tle,
1043 : const char *attrName)
1044 : {
1045 : TargetEntry *result;
2098 1046 141053 : CoerceToDomain *coerce_expr = NULL;
1047 : Node *src_expr;
6878 tgl 1048 ECB : Node *prior_expr;
1049 : Node *src_input;
1050 : Node *prior_input;
1051 : Node *priorbottom;
1052 : Node *newexpr;
7674 1053 :
7674 tgl 1054 GIC 141053 : if (prior_tle == NULL)
1055 : {
1056 : /*
1057 : * Normal case where this is the first assignment to the attribute.
1058 : */
1059 140944 : return src_tle;
1060 : }
7674 tgl 1061 ECB :
1062 : /*----------
1063 : * Multiple assignments to same attribute. Allow only if all are
1064 : * FieldStore or SubscriptingRef assignment operations. This is a bit
1065 : * tricky because what we may actually be looking at is a nest of
6878 1066 : * such nodes; consider
1067 : * UPDATE tab SET col.fld1.subfld1 = x, col.fld2.subfld2 = y
1068 : * The two expressions produced by the parser will look like
1069 : * FieldStore(col, fld1, FieldStore(placeholder, subfld1, x))
1070 : * FieldStore(col, fld2, FieldStore(placeholder, subfld2, y))
1071 : * However, we can ignore the substructure and just consider the top
1072 : * FieldStore or SubscriptingRef from each assignment, because it works to
1073 : * combine these as
1074 : * FieldStore(FieldStore(col, fld1,
1075 : * FieldStore(placeholder, subfld1, x)),
1076 : * fld2, FieldStore(placeholder, subfld2, y))
1077 : * Note the leftmost expression goes on the inside so that the
1078 : * assignments appear to occur left-to-right.
1079 : *
1080 : * For FieldStore, instead of nesting we can generate a single
1081 : * FieldStore with multiple target fields. We must nest when
1082 : * SubscriptingRefs are involved though.
1083 : *
1084 : * As a further complication, the destination column might be a domain,
1085 : * resulting in each assignment containing a CoerceToDomain node over a
1086 : * FieldStore or SubscriptingRef. These should have matching target
1087 : * domains, so we strip them and reconstitute a single CoerceToDomain over
1088 : * the combined FieldStore/SubscriptingRef nodes. (Notice that this has the
1089 : * result that the domain's checks are applied only after we do all the
1090 : * field or element updates, not after each one. This is arguably desirable.)
1091 : *----------
1092 : */
6878 tgl 1093 GIC 109 : src_expr = (Node *) src_tle->expr;
1094 109 : prior_expr = (Node *) prior_tle->expr;
1095 :
2098 1096 109 : if (src_expr && IsA(src_expr, CoerceToDomain) &&
1097 30 : prior_expr && IsA(prior_expr, CoerceToDomain) &&
1098 30 : ((CoerceToDomain *) src_expr)->resulttype ==
1099 30 : ((CoerceToDomain *) prior_expr)->resulttype)
2098 tgl 1100 ECB : {
1101 : /* we assume without checking that resulttypmod/resultcollid match */
2098 tgl 1102 GIC 30 : coerce_expr = (CoerceToDomain *) src_expr;
2098 tgl 1103 CBC 30 : src_expr = (Node *) ((CoerceToDomain *) src_expr)->arg;
1104 30 : prior_expr = (Node *) ((CoerceToDomain *) prior_expr)->arg;
2098 tgl 1105 ECB : }
1106 :
6878 tgl 1107 GIC 109 : src_input = get_assignment_input(src_expr);
1108 109 : prior_input = get_assignment_input(prior_expr);
6878 tgl 1109 CBC 109 : if (src_input == NULL ||
1110 100 : prior_input == NULL ||
1111 100 : exprType(src_expr) != exprType(prior_expr))
7198 tgl 1112 GIC 9 : ereport(ERROR,
1113 : (errcode(ERRCODE_SYNTAX_ERROR),
7136 peter_e 1114 ECB : errmsg("multiple assignments to same column \"%s\"",
7181 tgl 1115 : attrName)));
7674 1116 :
1117 : /*
6385 bruce 1118 : * Prior TLE could be a nest of assignments if we do this more than once.
7674 tgl 1119 : */
6878 tgl 1120 GIC 100 : priorbottom = prior_input;
1121 : for (;;)
1122 21 : {
6797 bruce 1123 121 : Node *newbottom = get_assignment_input(priorbottom);
1124 :
6878 tgl 1125 121 : if (newbottom == NULL)
1126 100 : break; /* found the original Var reference */
6878 tgl 1127 CBC 21 : priorbottom = newbottom;
1128 : }
1129 100 : if (!equal(priorbottom, src_input))
7198 tgl 1130 LBC 0 : ereport(ERROR,
1131 : (errcode(ERRCODE_SYNTAX_ERROR),
7136 peter_e 1132 ECB : errmsg("multiple assignments to same column \"%s\"",
7181 tgl 1133 : attrName)));
7674 1134 :
1135 : /*
1136 : * Looks OK to nest 'em.
7674 tgl 1137 EUB : */
6878 tgl 1138 GIC 100 : if (IsA(src_expr, FieldStore))
1139 : {
6797 bruce 1140 33 : FieldStore *fstore = makeNode(FieldStore);
1141 :
6878 tgl 1142 33 : if (IsA(prior_expr, FieldStore))
1143 : {
1144 : /* combine the two */
6878 tgl 1145 CBC 33 : memcpy(fstore, prior_expr, sizeof(FieldStore));
6878 tgl 1146 GIC 33 : fstore->newvals =
1336 tgl 1147 CBC 33 : list_concat_copy(((FieldStore *) prior_expr)->newvals,
1336 tgl 1148 GIC 33 : ((FieldStore *) src_expr)->newvals);
6878 tgl 1149 CBC 33 : fstore->fieldnums =
1336 tgl 1150 GIC 33 : list_concat_copy(((FieldStore *) prior_expr)->fieldnums,
1151 33 : ((FieldStore *) src_expr)->fieldnums);
6878 tgl 1152 ECB : }
1153 : else
1154 : {
1155 : /* general case, just nest 'em */
6878 tgl 1156 LBC 0 : memcpy(fstore, src_expr, sizeof(FieldStore));
1157 0 : fstore->arg = (Expr *) prior_expr;
6878 tgl 1158 ECB : }
6878 tgl 1159 GIC 33 : newexpr = (Node *) fstore;
1160 : }
1528 alvherre 1161 67 : else if (IsA(src_expr, SubscriptingRef))
1162 : {
1528 alvherre 1163 GBC 67 : SubscriptingRef *sbsref = makeNode(SubscriptingRef);
6878 tgl 1164 EUB :
1528 alvherre 1165 GIC 67 : memcpy(sbsref, src_expr, sizeof(SubscriptingRef));
1528 alvherre 1166 CBC 67 : sbsref->refexpr = (Expr *) prior_expr;
1528 alvherre 1167 GIC 67 : newexpr = (Node *) sbsref;
6878 tgl 1168 ECB : }
1169 : else
1170 : {
5911 bruce 1171 UIC 0 : elog(ERROR, "cannot happen");
6878 tgl 1172 ECB : newexpr = NULL;
1173 : }
7674 1174 :
2098 tgl 1175 GIC 100 : if (coerce_expr)
1176 : {
1177 : /* put back the CoerceToDomain */
2098 tgl 1178 GBC 30 : CoerceToDomain *newcoerce = makeNode(CoerceToDomain);
1179 :
2098 tgl 1180 GIC 30 : memcpy(newcoerce, coerce_expr, sizeof(CoerceToDomain));
1181 30 : newcoerce->arg = (Expr *) newexpr;
2098 tgl 1182 CBC 30 : newexpr = (Node *) newcoerce;
1183 : }
1184 :
6577 1185 100 : result = flatCopyTargetEntry(src_tle);
6577 tgl 1186 GIC 100 : result->expr = (Expr *) newexpr;
6577 tgl 1187 CBC 100 : return result;
7674 tgl 1188 ECB : }
1189 :
1190 : /*
1191 : * If node is an assignment node, return its input; else return NULL
6878 1192 : */
1193 : static Node *
6878 tgl 1194 CBC 339 : get_assignment_input(Node *node)
1195 : {
6878 tgl 1196 GIC 339 : if (node == NULL)
6878 tgl 1197 UIC 0 : return NULL;
6878 tgl 1198 GIC 339 : if (IsA(node, FieldStore))
1199 : {
1200 66 : FieldStore *fstore = (FieldStore *) node;
6878 tgl 1201 ECB :
6878 tgl 1202 GIC 66 : return (Node *) fstore->arg;
6878 tgl 1203 ECB : }
1528 alvherre 1204 GBC 273 : else if (IsA(node, SubscriptingRef))
6878 tgl 1205 ECB : {
1528 alvherre 1206 GIC 155 : SubscriptingRef *sbsref = (SubscriptingRef *) node;
6878 tgl 1207 ECB :
1528 alvherre 1208 GIC 155 : if (sbsref->refassgnexpr == NULL)
6878 tgl 1209 LBC 0 : return NULL;
1210 :
1528 alvherre 1211 CBC 155 : return (Node *) sbsref->refexpr;
1212 : }
1528 alvherre 1213 ECB :
6878 tgl 1214 GIC 118 : return NULL;
6878 tgl 1215 ECB : }
7674 tgl 1216 EUB :
1217 : /*
7674 tgl 1218 ECB : * Make an expression tree for the default value for a column.
1219 : *
1220 : * If there is no default, return a NULL instead.
1221 : */
1222 : Node *
7674 tgl 1223 GIC 95629 : build_column_default(Relation rel, int attrno)
1224 : {
1225 95629 : TupleDesc rd_att = rel->rd_att;
2058 andres 1226 95629 : Form_pg_attribute att_tup = TupleDescAttr(rd_att, attrno - 1);
7674 tgl 1227 95629 : Oid atttype = att_tup->atttypid;
1228 95629 : int32 atttypmod = att_tup->atttypmod;
1229 95629 : Node *expr = NULL;
7674 tgl 1230 ECB : Oid exprtype;
1231 :
1892 peter_e 1232 CBC 95629 : if (att_tup->attidentity)
1892 peter_e 1233 ECB : {
1892 peter_e 1234 CBC 187 : NextValueExpr *nve = makeNode(NextValueExpr);
1892 peter_e 1235 ECB :
1357 peter 1236 CBC 187 : nve->seqid = getIdentitySequence(RelationGetRelid(rel), attrno, false);
1892 peter_e 1237 GIC 187 : nve->typeId = att_tup->atttypid;
1238 :
1892 peter_e 1239 CBC 187 : return (Node *) nve;
1240 : }
1892 peter_e 1241 ECB :
1242 : /*
733 tgl 1243 : * If relation has a default for this column, fetch that expression.
7674 1244 : */
733 tgl 1245 GIC 95442 : if (att_tup->atthasdef)
7674 tgl 1246 ECB : {
733 tgl 1247 GIC 73594 : if (rd_att->constr && rd_att->constr->num_defval > 0)
1248 : {
1249 73594 : AttrDefault *defval = rd_att->constr->defval;
1250 73594 : int ndef = rd_att->constr->num_defval;
1251 :
733 tgl 1252 CBC 110980 : while (--ndef >= 0)
1253 : {
1254 110980 : if (attrno == defval[ndef].adnum)
1255 : {
733 tgl 1256 ECB : /* Found it, convert string representation to node tree. */
733 tgl 1257 CBC 73594 : expr = stringToNode(defval[ndef].adbin);
733 tgl 1258 GIC 73594 : break;
733 tgl 1259 ECB : }
1260 : }
7674 1261 : }
733 tgl 1262 GIC 73594 : if (expr == NULL)
733 tgl 1263 UIC 0 : elog(ERROR, "default expression not found for attribute %d of relation \"%s\"",
733 tgl 1264 ECB : attrno, RelationGetRelationName(rel));
7674 1265 : }
1266 :
1267 : /*
1268 : * No per-column default, so look for a default for the type itself. But
1471 peter 1269 : * not for generated columns.
1471 peter 1270 EUB : */
1471 peter 1271 GIC 95442 : if (expr == NULL && !att_tup->attgenerated)
6947 tgl 1272 21848 : expr = get_typdefault(atttype);
1273 :
7674 1274 95442 : if (expr == NULL)
1275 21736 : return NULL; /* No default anywhere */
1276 :
1277 : /*
7194 tgl 1278 ECB : * Make sure the value is coerced to the target column type; this will
1279 : * generally be true already, but there seem to be some corner cases
1280 : * involving domain defaults where it might not be true. This should match
6385 bruce 1281 : * the parser's processing of non-defaulted expressions --- see
6094 mail 1282 : * transformAssignedExpr().
1283 : */
7674 tgl 1284 GIC 73706 : exprtype = exprType(expr);
1285 :
7188 bruce 1286 73706 : expr = coerce_to_target_type(NULL, /* no UNKNOWN params here */
1287 : expr, exprtype,
1288 : atttype, atttypmod,
1289 : COERCION_ASSIGNMENT,
1290 : COERCE_IMPLICIT_CAST,
5337 tgl 1291 ECB : -1);
7508 tgl 1292 GIC 73706 : if (expr == NULL)
7198 tgl 1293 LBC 0 : ereport(ERROR,
1294 : (errcode(ERRCODE_DATATYPE_MISMATCH),
1295 : errmsg("column \"%s\" is of type %s"
1296 : " but default expression is of type %s",
1297 : NameStr(att_tup->attname),
1298 : format_type_be(atttype),
7198 tgl 1299 ECB : format_type_be(exprtype)),
2118 tgl 1300 EUB : errhint("You will need to rewrite or cast the expression.")));
1301 :
7674 tgl 1302 GIC 73706 : return expr;
1303 : }
1304 :
1305 :
1306 : /* Does VALUES RTE contain any SetToDefault items? */
1307 : static bool
6094 mail 1308 2024 : searchForDefault(RangeTblEntry *rte)
6094 mail 1309 ECB : {
1310 : ListCell *lc;
1311 :
6094 mail 1312 GIC 78527 : foreach(lc, rte->values_lists)
1313 : {
6031 bruce 1314 76634 : List *sublist = (List *) lfirst(lc);
6031 bruce 1315 ECB : ListCell *lc2;
1316 :
6094 mail 1317 GIC 159135 : foreach(lc2, sublist)
1318 : {
6031 bruce 1319 CBC 82632 : Node *col = (Node *) lfirst(lc2);
1320 :
6094 mail 1321 82632 : if (IsA(col, SetToDefault))
6094 mail 1322 GIC 131 : return true;
1323 : }
6094 mail 1324 ECB : }
6094 mail 1325 GIC 1893 : return false;
6094 mail 1326 ECB : }
1327 :
868 tgl 1328 :
1329 : /*
1330 : * Search a VALUES RTE for columns that contain only SetToDefault items,
1331 : * returning a Bitmapset containing the attribute numbers of any such columns.
1332 : */
1333 : static Bitmapset *
868 tgl 1334 GIC 41 : findDefaultOnlyColumns(RangeTblEntry *rte)
1335 : {
1336 41 : Bitmapset *default_only_cols = NULL;
1337 : ListCell *lc;
1338 :
1339 72 : foreach(lc, rte->values_lists)
1340 : {
868 tgl 1341 CBC 61 : List *sublist = (List *) lfirst(lc);
1342 : ListCell *lc2;
868 tgl 1343 ECB : int i;
1344 :
868 tgl 1345 GIC 61 : if (default_only_cols == NULL)
868 tgl 1346 ECB : {
1347 : /* Populate the initial result bitmap from the first row */
868 tgl 1348 CBC 41 : i = 0;
868 tgl 1349 GIC 122 : foreach(lc2, sublist)
1350 : {
1351 81 : Node *col = (Node *) lfirst(lc2);
868 tgl 1352 ECB :
868 tgl 1353 GIC 81 : i++;
1354 81 : if (IsA(col, SetToDefault))
868 tgl 1355 CBC 20 : default_only_cols = bms_add_member(default_only_cols, i);
868 tgl 1356 ECB : }
1357 : }
1358 : else
1359 : {
1360 : /* Update the result bitmap from this next row */
868 tgl 1361 CBC 20 : i = 0;
1362 59 : foreach(lc2, sublist)
1363 : {
868 tgl 1364 GIC 39 : Node *col = (Node *) lfirst(lc2);
1365 :
1366 39 : i++;
1367 39 : if (!IsA(col, SetToDefault))
868 tgl 1368 CBC 28 : default_only_cols = bms_del_member(default_only_cols, i);
868 tgl 1369 ECB : }
1370 : }
1371 :
1372 : /*
1373 : * If no column in the rows read so far contains only DEFAULT items,
1374 : * we are done.
1375 : */
868 tgl 1376 GIC 61 : if (bms_is_empty(default_only_cols))
1377 30 : break;
1378 : }
1379 :
1380 41 : return default_only_cols;
1381 : }
1382 :
868 tgl 1383 ECB :
6094 mail 1384 : /*
1385 : * When processing INSERT ... VALUES with a VALUES RTE (ie, multiple VALUES
1386 : * lists), we have to replace any DEFAULT items in the VALUES lists with
4564 tgl 1387 : * the appropriate default expressions. The other aspects of targetlist
1388 : * rewriting need be applied only to the query's targetlist proper.
1389 : *
1390 : * For an auto-updatable view, each DEFAULT item in the VALUES list is
1391 : * replaced with the default from the view, if it has one. Otherwise it is
1392 : * left untouched so that the underlying base relation's default can be
1393 : * applied instead (when we later recurse to here after rewriting the query
1394 : * to refer to the base relation instead of the view).
1395 : *
1396 : * For other types of relation, including rule- and trigger-updatable views,
1397 : * all DEFAULT items are replaced, and if the target relation doesn't have a
1398 : * default, the value is explicitly set to NULL.
1399 : *
1400 : * Also, if a DEFAULT item is found in a column mentioned in unused_cols,
1401 : * it is explicitly set to NULL. This happens for columns in the VALUES RTE
1402 : * whose corresponding targetlist entries have already been replaced with the
1403 : * relation's default expressions, so that any values in those columns of the
1404 : * VALUES RTE are no longer used. This can happen for identity and generated
1405 : * columns (if INSERT ... OVERRIDING USER VALUE is used, or all the values to
1406 : * be inserted are DEFAULT). In principle we could replace all entries in
1407 : * such a column with NULL, whether DEFAULT or not; but it doesn't seem worth
1408 : * the trouble.
1409 : *
1410 : * Note that we may have subscripted or field assignment targetlist entries,
1411 : * as well as more complex expressions from already-replaced DEFAULT items if
1412 : * we have recursed to here for an auto-updatable view. However, it ought to
1413 : * be impossible for such entries to have DEFAULTs assigned to them, except
1414 : * for unused columns, as described above --- we should only have to replace
1415 : * DEFAULT items for targetlist entries that contain simple Vars referencing
1416 : * the VALUES RTE, or which are no longer referred to by the targetlist.
1417 : *
1418 : * Returns true if all DEFAULT items were replaced, and false if some were
1419 : * left untouched.
1420 : */
1421 : static bool
1498 dean.a.rasheed 1422 GIC 2024 : rewriteValuesRTE(Query *parsetree, RangeTblEntry *rte, int rti,
1423 : Relation target_relation,
1424 : Bitmapset *unused_cols)
1425 : {
1426 : List *newValues;
1427 : ListCell *lc;
1428 : bool isAutoUpdatableView;
1509 dean.a.rasheed 1429 ECB : bool allReplaced;
1430 : int numattrs;
1431 : int *attrnos;
1432 :
1433 : /* Steps below are not sensible for non-INSERT queries */
180 tgl 1434 GIC 2024 : Assert(parsetree->commandType == CMD_INSERT);
1435 2024 : Assert(rte->rtekind == RTE_VALUES);
1436 :
1437 : /*
1438 : * Rebuilding all the lists is a pretty expensive proposition in a big
1439 : * VALUES list, and it's a waste of time if there aren't any DEFAULT
1440 : * placeholders. So first scan to see if there are any.
6094 mail 1441 ECB : */
180 tgl 1442 CBC 2024 : if (!searchForDefault(rte))
1509 dean.a.rasheed 1443 GIC 1893 : return true; /* nothing to do */
1444 :
1445 : /*
1446 : * Scan the targetlist for entries referring to the VALUES RTE, and note
1447 : * the target attributes. As noted above, we should only need to do this
1448 : * for targetlist entries containing simple Vars --- nothing else in the
868 tgl 1449 ECB : * VALUES RTE should contain DEFAULT items (except possibly for unused
1450 : * columns), and we complain if such a thing does occur.
1451 : */
1498 dean.a.rasheed 1452 GIC 131 : numattrs = list_length(linitial(rte->values_lists));
1453 131 : attrnos = (int *) palloc0(numattrs * sizeof(int));
1454 :
1455 556 : foreach(lc, parsetree->targetList)
1456 : {
1457 425 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
1458 :
1498 dean.a.rasheed 1459 CBC 425 : if (IsA(tle->expr, Var))
1498 dean.a.rasheed 1460 ECB : {
1498 dean.a.rasheed 1461 GIC 358 : Var *var = (Var *) tle->expr;
1498 dean.a.rasheed 1462 ECB :
1498 dean.a.rasheed 1463 GIC 358 : if (var->varno == rti)
1498 dean.a.rasheed 1464 ECB : {
1498 dean.a.rasheed 1465 GIC 358 : int attrno = var->varattno;
1498 dean.a.rasheed 1466 ECB :
1498 dean.a.rasheed 1467 GIC 358 : Assert(attrno >= 1 && attrno <= numattrs);
1498 dean.a.rasheed 1468 CBC 358 : attrnos[attrno - 1] = tle->resno;
1469 : }
1498 dean.a.rasheed 1470 ECB : }
1471 : }
6094 mail 1472 :
1473 : /*
1509 dean.a.rasheed 1474 : * Check if the target relation is an auto-updatable view, in which case
1475 : * unresolved defaults will be left untouched rather than being set to
1476 : * NULL.
1477 : */
1509 dean.a.rasheed 1478 GIC 131 : isAutoUpdatableView = false;
180 tgl 1479 131 : if (target_relation->rd_rel->relkind == RELKIND_VIEW &&
1509 dean.a.rasheed 1480 45 : !view_has_instead_trigger(target_relation, CMD_INSERT))
1481 : {
1482 : List *locks;
1483 : bool hasUpdate;
1484 : bool found;
1509 dean.a.rasheed 1485 ECB : ListCell *l;
1486 :
1487 : /* Look for an unconditional DO INSTEAD rule */
1509 dean.a.rasheed 1488 GIC 39 : locks = matchLocks(CMD_INSERT, target_relation->rd_rules,
1489 : parsetree->resultRelation, parsetree, &hasUpdate);
1490 :
1491 39 : found = false;
1492 51 : foreach(l, locks)
1493 : {
1494 18 : RewriteRule *rule_lock = (RewriteRule *) lfirst(l);
1509 dean.a.rasheed 1495 ECB :
1509 dean.a.rasheed 1496 GIC 18 : if (rule_lock->isInstead &&
1497 6 : rule_lock->qual == NULL)
1509 dean.a.rasheed 1498 ECB : {
1509 dean.a.rasheed 1499 CBC 6 : found = true;
1509 dean.a.rasheed 1500 GIC 6 : break;
1509 dean.a.rasheed 1501 ECB : }
1502 : }
1503 :
1504 : /*
1505 : * If we didn't find an unconditional DO INSTEAD rule, assume that the
1506 : * view is auto-updatable. If it isn't, rewriteTargetView() will
1507 : * throw an error.
1508 : */
1509 dean.a.rasheed 1509 GIC 39 : if (!found)
1510 33 : isAutoUpdatableView = true;
1511 : }
1512 :
6094 mail 1513 131 : newValues = NIL;
1509 dean.a.rasheed 1514 131 : allReplaced = true;
6094 mail 1515 399 : foreach(lc, rte->values_lists)
6094 mail 1516 ECB : {
6031 bruce 1517 CBC 268 : List *sublist = (List *) lfirst(lc);
6031 bruce 1518 GIC 268 : List *newList = NIL;
1519 : ListCell *lc2;
1498 dean.a.rasheed 1520 ECB : int i;
1521 :
1498 dean.a.rasheed 1522 CBC 268 : Assert(list_length(sublist) == numattrs);
1523 :
1524 268 : i = 0;
1525 1099 : foreach(lc2, sublist)
1526 : {
6031 bruce 1527 GIC 831 : Node *col = (Node *) lfirst(lc2);
1498 dean.a.rasheed 1528 831 : int attrno = attrnos[i++];
6094 mail 1529 ECB :
6094 mail 1530 GIC 831 : if (IsA(col, SetToDefault))
6094 mail 1531 ECB : {
1532 : Form_pg_attribute att_tup;
1533 : Node *new_expr;
1534 :
868 tgl 1535 : /*
1536 : * If this column isn't used, just replace the DEFAULT with
1537 : * NULL (attrno will be 0 in this case because the targetlist
1538 : * entry will have been replaced by the default expression).
1539 : */
868 tgl 1540 GIC 394 : if (bms_is_member(i, unused_cols))
1541 34 : {
1542 34 : SetToDefault *def = (SetToDefault *) col;
1543 :
1544 34 : newList = lappend(newList,
1545 34 : makeNullConst(def->typeId,
1546 : def->typeMod,
868 tgl 1547 ECB : def->collation));
868 tgl 1548 CBC 34 : continue;
868 tgl 1549 ECB : }
1550 :
1498 dean.a.rasheed 1551 CBC 360 : if (attrno == 0)
1498 dean.a.rasheed 1552 LBC 0 : elog(ERROR, "cannot set value in column %d to DEFAULT", i);
180 tgl 1553 GIC 360 : Assert(attrno > 0 && attrno <= target_relation->rd_att->natts);
2058 andres 1554 360 : att_tup = TupleDescAttr(target_relation->rd_att, attrno - 1);
6094 mail 1555 ECB :
180 tgl 1556 GIC 360 : if (!att_tup->attisdropped)
6094 mail 1557 360 : new_expr = build_column_default(target_relation, attrno);
6094 mail 1558 ECB : else
6031 bruce 1559 UBC 0 : new_expr = NULL; /* force a NULL if dropped */
6094 mail 1560 ECB :
1561 : /*
1562 : * If there is no default (ie, default is effectively NULL),
1509 dean.a.rasheed 1563 : * we've got to explicitly set the column to NULL, unless the
1564 : * target relation is an auto-updatable view.
1565 : */
6094 mail 1566 GBC 360 : if (!new_expr)
1567 : {
1509 dean.a.rasheed 1568 GIC 165 : if (isAutoUpdatableView)
1569 : {
1570 : /* Leave the value untouched */
1571 63 : newList = lappend(newList, col);
1572 63 : allReplaced = false;
1509 dean.a.rasheed 1573 CBC 63 : continue;
1574 : }
1509 dean.a.rasheed 1575 ECB :
6094 mail 1576 GIC 102 : new_expr = (Node *) makeConst(att_tup->atttypid,
1577 : -1,
4398 tgl 1578 ECB : att_tup->attcollation,
6094 mail 1579 CBC 102 : att_tup->attlen,
6094 mail 1580 ECB : (Datum) 0,
1581 : true, /* isnull */
6094 mail 1582 GIC 102 : att_tup->attbyval);
6094 mail 1583 ECB : /* this is to catch a NOT NULL domain constraint */
6094 mail 1584 GIC 102 : new_expr = coerce_to_domain(new_expr,
1585 : InvalidOid, -1,
6094 mail 1586 ECB : att_tup->atttypid,
1587 : COERCION_IMPLICIT,
1588 : COERCE_IMPLICIT_CAST,
5337 tgl 1589 : -1,
1590 : false);
6094 mail 1591 : }
6094 mail 1592 GIC 297 : newList = lappend(newList, new_expr);
1593 : }
1594 : else
1595 437 : newList = lappend(newList, col);
1596 : }
1597 268 : newValues = lappend(newValues, newList);
1598 : }
6094 mail 1599 CBC 131 : rte->values_lists = newValues;
1600 :
1498 dean.a.rasheed 1601 GIC 131 : pfree(attrnos);
1498 dean.a.rasheed 1602 ECB :
1509 dean.a.rasheed 1603 GIC 131 : return allReplaced;
6094 mail 1604 ECB : }
1605 :
180 tgl 1606 : /*
1607 : * Mop up any remaining DEFAULT items in the given VALUES RTE by
1608 : * replacing them with NULL constants.
1609 : *
1610 : * This is used for the product queries generated by DO ALSO rules attached to
1611 : * an auto-updatable view. The action can't depend on the "target relation"
1612 : * since the product query might not have one (it needn't be an INSERT).
1613 : * Essentially, such queries are treated as being attached to a rule-updatable
1614 : * view.
1615 : */
1616 : static void
180 tgl 1617 GIC 12 : rewriteValuesRTEToNulls(Query *parsetree, RangeTblEntry *rte)
1618 : {
1619 : List *newValues;
1620 : ListCell *lc;
1621 :
1622 12 : newValues = NIL;
1623 36 : foreach(lc, rte->values_lists)
180 tgl 1624 ECB : {
180 tgl 1625 GIC 24 : List *sublist = (List *) lfirst(lc);
1626 24 : List *newList = NIL;
1627 : ListCell *lc2;
1628 :
180 tgl 1629 CBC 102 : foreach(lc2, sublist)
180 tgl 1630 ECB : {
180 tgl 1631 GIC 78 : Node *col = (Node *) lfirst(lc2);
180 tgl 1632 ECB :
180 tgl 1633 CBC 78 : if (IsA(col, SetToDefault))
1634 : {
180 tgl 1635 GIC 33 : SetToDefault *def = (SetToDefault *) col;
180 tgl 1636 ECB :
180 tgl 1637 GIC 33 : newList = lappend(newList, makeNullConst(def->typeId,
180 tgl 1638 ECB : def->typeMod,
1639 : def->collation));
1640 : }
1641 : else
180 tgl 1642 CBC 45 : newList = lappend(newList, col);
1643 : }
1644 24 : newValues = lappend(newValues, newList);
1645 : }
180 tgl 1646 GIC 12 : rte->values_lists = newValues;
1647 12 : }
1648 :
6094 mail 1649 ECB :
1650 : /*
8227 tgl 1651 : * matchLocks -
1652 : * match the list of locks and returns the matching rules
8955 bruce 1653 : */
8227 tgl 1654 : static List *
8227 tgl 1655 GIC 53547 : matchLocks(CmdType event,
1656 : RuleLock *rulelocks,
1657 : int varno,
1658 : Query *parsetree,
1659 : bool *hasUpdate)
1660 : {
7477 1661 53547 : List *matching_locks = NIL;
8227 tgl 1662 ECB : int nlocks;
1663 : int i;
1664 :
7348 tgl 1665 GIC 53547 : if (rulelocks == NULL)
1666 51314 : return NIL;
1667 :
377 alvherre 1668 ECB : /* No rule support for MERGE */
377 alvherre 1669 GIC 2233 : if (parsetree->commandType == CMD_MERGE)
377 alvherre 1670 UIC 0 : return NIL;
1671 :
8227 tgl 1672 CBC 2233 : if (parsetree->commandType != CMD_SELECT)
8591 tgl 1673 ECB : {
8227 tgl 1674 GIC 2233 : if (parsetree->resultRelation != varno)
8227 tgl 1675 UIC 0 : return NIL;
8591 tgl 1676 ECB : }
8955 bruce 1677 EUB :
8227 tgl 1678 GIC 2233 : nlocks = rulelocks->numLocks;
8955 bruce 1679 ECB :
8227 tgl 1680 GIC 5255 : for (i = 0; i < nlocks; i++)
8720 bruce 1681 ECB : {
8227 tgl 1682 GBC 3022 : RewriteRule *oneLock = rulelocks->rules[i];
1683 :
2893 andres 1684 GIC 3022 : if (oneLock->event == CMD_UPDATE)
2893 andres 1685 CBC 315 : *hasUpdate = true;
1686 :
5865 JanWieck 1687 ECB : /*
1688 : * Suppress ON INSERT/UPDATE/DELETE rules that are disabled or
5624 bruce 1689 : * configured to not fire during the current sessions replication
1690 : * role. ON SELECT rules will always be applied in order to keep views
1691 : * working even in LOCAL or REPLICA role.
5865 JanWieck 1692 : */
5865 JanWieck 1693 GIC 3022 : if (oneLock->event != CMD_SELECT)
1694 : {
1695 1299 : if (SessionReplicationRole == SESSION_REPLICATION_ROLE_REPLICA)
1696 : {
1697 6 : if (oneLock->enabled == RULE_FIRES_ON_ORIGIN ||
1698 3 : oneLock->enabled == RULE_DISABLED)
1699 3 : continue;
5865 JanWieck 1700 ECB : }
1701 : else /* ORIGIN or LOCAL ROLE */
1702 : {
5865 JanWieck 1703 GIC 1293 : if (oneLock->enabled == RULE_FIRES_ON_REPLICA ||
5865 JanWieck 1704 CBC 1290 : oneLock->enabled == RULE_DISABLED)
1705 6 : continue;
5865 JanWieck 1706 ECB : }
1707 : }
1708 :
8227 tgl 1709 GIC 3013 : if (oneLock->event == event)
8546 tgl 1710 ECB : {
8227 tgl 1711 CBC 762 : if (parsetree->commandType != CMD_SELECT ||
3503 kgrittn 1712 LBC 0 : rangeTableEntry_used((Node *) parsetree, varno, 0))
7477 tgl 1713 GIC 762 : matching_locks = lappend(matching_locks, oneLock);
1714 : }
1715 : }
8227 tgl 1716 ECB :
7477 tgl 1717 GIC 2233 : return matching_locks;
8955 bruce 1718 ECB : }
8955 bruce 1719 EUB :
8397 bruce 1720 ECB :
1721 : /*
1722 : * ApplyRetrieveRule - expand an ON SELECT rule
1723 : */
8227 tgl 1724 : static Query *
8227 tgl 1725 GIC 5871 : ApplyRetrieveRule(Query *parsetree,
1726 : RewriteRule *rule,
1727 : int rt_index,
1728 : Relation relation,
1729 : List *activeRIRs)
1730 : {
1731 : Query *rule_action;
1732 : RangeTblEntry *rte;
1733 : RowMarkClause *rc;
1734 : int numCols;
1735 :
6888 neilc 1736 5871 : if (list_length(rule->actions) != 1)
7198 tgl 1737 UIC 0 : elog(ERROR, "expected just one rule action");
8227 tgl 1738 GIC 5871 : if (rule->qual != NULL)
7198 tgl 1739 UIC 0 : elog(ERROR, "cannot handle qualified ON SELECT rule");
1740 :
4564 tgl 1741 GIC 5871 : if (rt_index == parsetree->resultRelation)
4564 tgl 1742 ECB : {
4564 tgl 1743 EUB : /*
4564 tgl 1744 ECB : * We have a view as the result relation of the query, and it wasn't
4564 tgl 1745 EUB : * rewritten by any rule. This case is supported if there is an
1746 : * INSTEAD OF trigger that will trap attempts to insert/update/delete
4564 tgl 1747 ECB : * view rows. The executor will check that; for the moment just plow
1748 : * ahead. We have two cases:
1749 : *
1750 : * For INSERT, we needn't do anything. The unmodified RTE will serve
1751 : * fine as the result relation.
1752 : *
1753 : * For UPDATE/DELETE, we need to expand the view so as to have source
1754 : * data for the operation. But we also need an unmodified RTE to
1755 : * serve as the target. So, copy the RTE and add the copy to the
1756 : * rangetable. Note that the copy does not get added to the jointree.
1757 : * Also note that there's a hack in fireRIRrules to avoid calling this
1758 : * function again when it arrives at the copied RTE.
1759 : */
4564 tgl 1760 GIC 156 : if (parsetree->commandType == CMD_INSERT)
1761 60 : return parsetree;
1762 96 : else if (parsetree->commandType == CMD_UPDATE ||
1763 27 : parsetree->commandType == CMD_DELETE)
1764 96 : {
1765 : RangeTblEntry *newrte;
1959 tgl 1766 ECB : Var *var;
1767 : TargetEntry *tle;
4564 1768 :
4564 tgl 1769 CBC 96 : rte = rt_fetch(rt_index, parsetree->rtable);
1770 96 : newrte = copyObject(rte);
4564 tgl 1771 GIC 96 : parsetree->rtable = lappend(parsetree->rtable, newrte);
1772 96 : parsetree->resultRelation = list_length(parsetree->rtable);
1773 :
1774 : /*
1775 : * For the most part, Vars referencing the view should remain as
1776 : * they are, meaning that they implicitly represent OLD values.
4564 tgl 1777 ECB : * But in the RETURNING list if any, we want such Vars to
1778 : * represent NEW values, so change them to reference the new RTE.
1779 : *
1780 : * Since ChangeVarNodes scribbles on the tree in-place, copy the
1781 : * RETURNING list first for safety.
1782 : */
4564 tgl 1783 GIC 96 : parsetree->returningList = copyObject(parsetree->returningList);
1784 96 : ChangeVarNodes((Node *) parsetree->returningList, rt_index,
1785 : parsetree->resultRelation, 0);
1786 :
1959 tgl 1787 ECB : /*
1788 : * To allow the executor to compute the original view row to pass
1789 : * to the INSTEAD OF trigger, we add a resjunk whole-row Var
1790 : * referencing the original RTE. This will later get expanded
1791 : * into a RowExpr computing all the OLD values of the view row.
1792 : */
1959 tgl 1793 CBC 96 : var = makeWholeRowVar(rte, rt_index, 0, false);
1959 tgl 1794 GIC 96 : tle = makeTargetEntry((Expr *) var,
1795 96 : list_length(parsetree->targetList) + 1,
1796 : pstrdup("wholerow"),
1797 : true);
1959 tgl 1798 EUB :
1959 tgl 1799 GIC 96 : parsetree->targetList = lappend(parsetree->targetList, tle);
1800 :
1801 : /* Now, continue with expanding the original view RTE */
1802 : }
1803 : else
4564 tgl 1804 UIC 0 : elog(ERROR, "unrecognized commandType: %d",
1805 : (int) parsetree->commandType);
1806 : }
1807 :
1808 : /*
1821 tgl 1809 ECB : * Check if there's a FOR [KEY] UPDATE/SHARE clause applying to this view.
1810 : *
1811 : * Note: we needn't explicitly consider any such clauses appearing in
1812 : * ancestor query levels; their effects have already been pushed down to
1813 : * here by markQueryForLocking, and will be reflected in "rc".
1814 : */
4911 tgl 1815 GIC 5811 : rc = get_parse_rowmark(parsetree, rt_index);
4911 tgl 1816 ECB :
1817 : /*
6385 bruce 1818 : * Make a modifiable copy of the view query, and acquire needed locks on
1819 : * the relations it mentions. Force at least RowShareLock for all such
1820 : * rels if there's a FOR [KEY] UPDATE/SHARE clause affecting this view.
1821 : */
6892 neilc 1822 GIC 5811 : rule_action = copyObject(linitial(rule->actions));
1823 :
1821 tgl 1824 5811 : AcquireRewriteLocks(rule_action, true, (rc != NULL));
6519 tgl 1825 ECB :
1821 1826 : /*
1827 : * If FOR [KEY] UPDATE/SHARE of view, mark all the contained tables as
1828 : * implicit FOR [KEY] UPDATE/SHARE, the same as the parser would have done
1829 : * if the view's subquery had been written out explicitly.
1830 : */
1821 tgl 1831 GIC 5811 : if (rc != NULL)
1821 tgl 1832 CBC 48 : markQueryForLocking(rule_action, (Node *) rule_action->jointree,
1833 : rc->strength, rc->waitPolicy, true);
1834 :
1835 : /*
1836 : * Recursively expand any view references inside the view.
1837 : */
1821 tgl 1838 GIC 5811 : rule_action = fireRIRrules(rule_action, activeRIRs);
1839 :
1840 : /*
1841 : * Now, plug the view query in as a subselect, converting the relation's
1842 : * original RTE to a subquery RTE.
1843 : */
8227 tgl 1844 CBC 5796 : rte = rt_fetch(rt_index, parsetree->rtable);
8955 bruce 1845 ECB :
7698 tgl 1846 CBC 5796 : rte->rtekind = RTE_SUBQUERY;
8227 tgl 1847 GIC 5796 : rte->subquery = rule_action;
1664 1848 5796 : rte->security_barrier = RelationIsSecurityView(relation);
8397 bruce 1849 ECB :
88 tgl 1850 : /*
1851 : * Clear fields that should not be set in a subquery RTE. Note that we
1852 : * leave the relid, rellockmode, and perminfoindex fields set, so that the
1853 : * view relation can be appropriately locked before execution and its
1854 : * permissions checked.
1855 : */
81 tgl 1856 GNC 5796 : rte->relkind = 0;
1857 5796 : rte->tablesample = NULL;
1858 5796 : rte->inh = false; /* must not be set for a subquery */
1859 :
1860 : /*
1861 : * Since we allow CREATE OR REPLACE VIEW to add columns to a view, the
33 tgl 1862 ECB : * rule_action might emit more columns than we expected when the current
1863 : * query was parsed. Various places expect rte->eref->colnames to be
1864 : * consistent with the non-junk output columns of the subquery, so patch
1865 : * things up if necessary by adding some dummy column names.
1866 : */
33 tgl 1867 GBC 5796 : numCols = ExecCleanTargetListLength(rule_action->targetList);
33 tgl 1868 CBC 5805 : while (list_length(rte->eref->colnames) < numCols)
1869 : {
1870 9 : rte->eref->colnames = lappend(rte->eref->colnames,
1871 9 : makeString(pstrdup("?column?")));
1872 : }
33 tgl 1873 ECB :
8591 tgl 1874 GIC 5796 : return parsetree;
1875 : }
1876 :
8158 tgl 1877 ECB : /*
1878 : * Recursively mark all relations used by a view as FOR [KEY] UPDATE/SHARE.
1879 : *
1880 : * This may generate an invalid query, eg if some sub-query uses an
1881 : * aggregate. We leave it to the planner to detect that.
8158 tgl 1882 EUB : *
1883 : * NB: this must agree with the parser's transformLockingClause() routine.
1884 : * However, we used to have to avoid marking a view's OLD and NEW rels for
1885 : * updating, which motivated scanning the jointree to determine which rels
1886 : * are used. Possibly that could now be simplified into just scanning the
1887 : * rangetable as the parser does.
1888 : */
1889 : static void
4911 tgl 1890 GIC 96 : markQueryForLocking(Query *qry, Node *jtnode,
1891 : LockClauseStrength strength, LockWaitPolicy waitPolicy,
3106 alvherre 1892 ECB : bool pushedDown)
1893 : {
5883 tgl 1894 CBC 96 : if (jtnode == NULL)
5883 tgl 1895 UIC 0 : return;
5883 tgl 1896 GIC 96 : if (IsA(jtnode, RangeTblRef))
8158 tgl 1897 ECB : {
5883 tgl 1898 CBC 48 : int rti = ((RangeTblRef *) jtnode)->rtindex;
5883 tgl 1899 GIC 48 : RangeTblEntry *rte = rt_fetch(rti, qry->rtable);
8158 tgl 1900 EUB :
7698 tgl 1901 GIC 48 : if (rte->rtekind == RTE_RELATION)
8158 tgl 1902 EUB : {
1903 : RTEPermissionInfo *perminfo;
1904 :
3106 alvherre 1905 GIC 48 : applyLockingClause(qry, rti, strength, waitPolicy, pushedDown);
1906 :
124 alvherre 1907 GNC 48 : perminfo = getRTEPermissionInfo(qry->rteperminfos, rte);
1908 48 : perminfo->requiredPerms |= ACL_SELECT_FOR_UPDATE;
8158 tgl 1909 EUB : }
7698 tgl 1910 UIC 0 : else if (rte->rtekind == RTE_SUBQUERY)
1911 : {
3106 alvherre 1912 UBC 0 : applyLockingClause(qry, rti, strength, waitPolicy, pushedDown);
1913 : /* FOR UPDATE/SHARE of subquery is propagated to subquery's rels */
5883 tgl 1914 UIC 0 : markQueryForLocking(rte->subquery, (Node *) rte->subquery->jointree,
1915 : strength, waitPolicy, true);
1916 : }
1917 : /* other RTE types are unaffected by FOR UPDATE */
1918 : }
5883 tgl 1919 GIC 48 : else if (IsA(jtnode, FromExpr))
1920 : {
1921 48 : FromExpr *f = (FromExpr *) jtnode;
1922 : ListCell *l;
1923 :
1924 96 : foreach(l, f->fromlist)
3106 alvherre 1925 48 : markQueryForLocking(qry, lfirst(l), strength, waitPolicy, pushedDown);
1926 : }
5883 tgl 1927 UIC 0 : else if (IsA(jtnode, JoinExpr))
1928 : {
1929 0 : JoinExpr *j = (JoinExpr *) jtnode;
1930 :
3106 alvherre 1931 LBC 0 : markQueryForLocking(qry, j->larg, strength, waitPolicy, pushedDown);
3106 alvherre 1932 UIC 0 : markQueryForLocking(qry, j->rarg, strength, waitPolicy, pushedDown);
5883 tgl 1933 ECB : }
1934 : else
5883 tgl 1935 LBC 0 : elog(ERROR, "unrecognized node type: %d",
1936 : (int) nodeTag(jtnode));
8158 tgl 1937 ECB : }
1938 :
1939 :
8591 1940 : /*
1941 : * fireRIRonSubLink -
1942 : * Apply fireRIRrules() to each SubLink (subselect in expression) found
1943 : * in the given tree.
1944 : *
1945 : * NOTE: although this has the form of a walker, we cheat and modify the
1946 : * SubLink nodes in-place. It is caller's responsibility to ensure that
1947 : * no unwanted side-effects occur!
1948 : *
8244 1949 : * This is unlike most of the other routines that recurse into subselects,
1950 : * because we must take control at the SubLink node in order to replace
1951 : * the SubLink's subselect link with the possibly-rewritten subquery.
1952 : */
1953 : static bool
7348 tgl 1954 GIC 1023626 : fireRIRonSubLink(Node *node, List *activeRIRs)
1955 : {
8955 bruce 1956 1023626 : if (node == NULL)
8591 tgl 1957 224453 : return false;
1958 799173 : if (IsA(node, SubLink))
1959 : {
1960 22103 : SubLink *sub = (SubLink *) node;
1961 :
8591 tgl 1962 ECB : /* Do what we came for */
7348 tgl 1963 GIC 22103 : sub->subselect = (Node *) fireRIRrules((Query *) sub->subselect,
1821 tgl 1964 ECB : activeRIRs);
1965 : /* Fall through to process lefthand args of SubLink */
1966 : }
1967 :
1968 : /*
1969 : * Do NOT recurse into Query nodes, because fireRIRrules already processed
1970 : * subselects of subselects for us.
1971 : */
8227 tgl 1972 GIC 799137 : return expression_tree_walker(node, fireRIRonSubLink,
1973 : (void *) activeRIRs);
8955 bruce 1974 ECB : }
1975 :
1976 :
1977 : /*
1978 : * fireRIRrules -
1979 : * Apply all RIR rules on each rangetable entry in the given query
1821 tgl 1980 : *
1981 : * activeRIRs is a list of the OIDs of views we're already processing RIR
1982 : * rules for, used to detect/reject recursion.
1983 : */
1984 : static Query *
1821 tgl 1985 GIC 260644 : fireRIRrules(Query *parsetree, List *activeRIRs)
1986 : {
4564 1987 260644 : int origResultRelation = parsetree->resultRelation;
1988 : int rt_index;
5300 tgl 1989 ECB : ListCell *lc;
8955 bruce 1990 :
1991 : /*
1992 : * Expand SEARCH and CYCLE clauses in CTEs.
1993 : *
1994 : * This is just a convenient place to do this, since we are already
1995 : * looking at each Query.
1996 : */
797 peter 1997 GIC 262318 : foreach(lc, parsetree->cteList)
1998 : {
797 peter 1999 CBC 1677 : CommonTableExpr *cte = lfirst_node(CommonTableExpr, lc);
2000 :
2001 1677 : if (cte->search_clause || cte->cycle_clause)
2002 : {
797 peter 2003 GIC 72 : cte = rewriteSearchAndCycle(cte);
2004 69 : lfirst(lc) = cte;
2005 : }
2006 : }
2007 :
8397 bruce 2008 ECB : /*
2009 : * don't try to convert this into a foreach loop, because rtable list can
6385 2010 : * get changed each time through...
8585 tgl 2011 : */
8955 bruce 2012 GIC 260641 : rt_index = 0;
6888 neilc 2013 541379 : while (rt_index < list_length(parsetree->rtable))
2014 : {
2015 : RangeTblEntry *rte;
2016 : Relation rel;
8187 tgl 2017 ECB : List *locks;
2018 : RuleLock *rules;
2019 : RewriteRule *rule;
2020 : int i;
2021 :
8955 bruce 2022 GIC 280753 : ++rt_index;
2023 :
8560 tgl 2024 280753 : rte = rt_fetch(rt_index, parsetree->rtable);
2025 :
2026 : /*
2027 : * A subquery RTE can't have associated rules, so there's nothing to
2028 : * do to this level of the query, but we must recurse into the
2029 : * subquery to expand any rule references in it.
8227 tgl 2030 ECB : */
7698 tgl 2031 CBC 280753 : if (rte->rtekind == RTE_SUBQUERY)
2032 : {
1821 tgl 2033 GIC 19680 : rte->subquery = fireRIRrules(rte->subquery, activeRIRs);
8227 2034 19680 : continue;
2035 : }
2036 :
2037 : /*
2038 : * Joins and other non-relation RTEs can be ignored completely.
2039 : */
7698 tgl 2040 CBC 261073 : if (rte->rtekind != RTE_RELATION)
2041 57034 : continue;
7698 tgl 2042 ECB :
2043 : /*
2044 : * Always ignore RIR rules for materialized views referenced in
2045 : * queries. (This does not prevent refreshing MVs, since they aren't
2046 : * referenced in their own query definitions.)
2047 : *
2048 : * Note: in the future we might want to allow MVs to be conditionally
2049 : * expanded as if they were regular views, if they are not scannable.
2050 : * In that case this test would need to be postponed till after we've
3634 2051 : * opened the rel, so that we could check its state.
2052 : */
3634 tgl 2053 CBC 204039 : if (rte->relkind == RELKIND_MATVIEW)
3634 tgl 2054 GIC 229 : continue;
2055 :
2056 : /*
2057 : * In INSERT ... ON CONFLICT, ignore the EXCLUDED pseudo-relation;
2058 : * even if it points to a view, we needn't expand it, and should not
1709 tgl 2059 ECB : * because we want the RTE to remain of RTE_RELATION type. Otherwise,
2060 : * it would get changed to RTE_SUBQUERY type, which is an
2061 : * untested/unsupported situation.
2062 : */
1709 tgl 2063 GIC 203810 : if (parsetree->onConflict &&
2064 1494 : rt_index == parsetree->onConflict->exclRelIndex)
2065 557 : continue;
2066 :
8585 tgl 2067 ECB : /*
2068 : * If the table is not referenced in the query, then we ignore it.
2069 : * This prevents infinite expansion loop due to new rtable entries
2070 : * inserted by expansion of a rule. A table is referenced if it is
2071 : * part of the join set (a source table), or is referenced by any Var
6385 bruce 2072 : * nodes, or is the result table.
8585 tgl 2073 : */
6524 tgl 2074 GIC 203253 : if (rt_index != parsetree->resultRelation &&
6524 tgl 2075 CBC 151315 : !rangeTableEntry_used((Node *) parsetree, rt_index, 0))
8955 bruce 2076 3115 : continue;
2077 :
4564 tgl 2078 ECB : /*
2079 : * Also, if this is a new result relation introduced by
2080 : * ApplyRetrieveRule, we don't want to do anything more with it.
2081 : */
4564 tgl 2082 CBC 200138 : if (rt_index == parsetree->resultRelation &&
2083 : rt_index != origResultRelation)
4564 tgl 2084 GIC 96 : continue;
2085 :
2086 : /*
2087 : * We can use NoLock here since either the parser or
6519 tgl 2088 ECB : * AcquireRewriteLocks should have locked the rel already.
2089 : */
1539 andres 2090 GIC 200042 : rel = table_open(rte->relid, NoLock);
2091 :
8027 tgl 2092 ECB : /*
8027 tgl 2093 EUB : * Collect the RIR rules that we must apply
2094 : */
8585 tgl 2095 GIC 200042 : rules = rel->rd_rules;
3124 sfrost 2096 200042 : if (rules != NULL)
8720 bruce 2097 ECB : {
3124 sfrost 2098 GIC 6471 : locks = NIL;
3124 sfrost 2099 CBC 13924 : for (i = 0; i < rules->numLocks; i++)
2100 : {
2101 7453 : rule = rules->rules[i];
3124 sfrost 2102 GIC 7453 : if (rule->event != CMD_SELECT)
3124 sfrost 2103 CBC 1582 : continue;
2104 :
3124 sfrost 2105 GIC 5871 : locks = lappend(locks, rule);
2106 : }
2107 :
2108 : /*
2109 : * If we found any, apply them --- but first check for recursion!
3124 sfrost 2110 ECB : */
3124 sfrost 2111 GIC 6471 : if (locks != NIL)
2112 : {
2113 : ListCell *l;
3124 sfrost 2114 ECB :
3124 sfrost 2115 GIC 5871 : if (list_member_oid(activeRIRs, RelationGetRelid(rel)))
3124 sfrost 2116 UIC 0 : ereport(ERROR,
2117 : (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
3124 sfrost 2118 ECB : errmsg("infinite recursion detected in rules for relation \"%s\"",
2119 : RelationGetRelationName(rel))));
1362 tgl 2120 CBC 5871 : activeRIRs = lappend_oid(activeRIRs, RelationGetRelid(rel));
2121 :
3124 sfrost 2122 11727 : foreach(l, locks)
3124 sfrost 2123 ECB : {
3124 sfrost 2124 GIC 5871 : rule = lfirst(l);
2125 :
2126 5871 : parsetree = ApplyRetrieveRule(parsetree,
2127 : rule,
2128 : rt_index,
2129 : rel,
1821 tgl 2130 ECB : activeRIRs);
3124 sfrost 2131 : }
2132 :
1362 tgl 2133 GIC 5856 : activeRIRs = list_delete_last(activeRIRs);
2134 : }
2135 : }
2136 :
1539 andres 2137 200027 : table_close(rel, NoLock);
2138 : }
2139 :
5300 tgl 2140 ECB : /* Recurse into subqueries in WITH */
5300 tgl 2141 CBC 262300 : foreach(lc, parsetree->cteList)
2142 : {
2143 1674 : CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
2144 :
5300 tgl 2145 GIC 1674 : cte->ctequery = (Node *)
1821 2146 1674 : fireRIRrules((Query *) cte->ctequery, activeRIRs);
2147 : }
2148 :
2149 : /*
6385 bruce 2150 ECB : * Recurse into sublink subqueries, too. But we already did the ones in
2151 : * the rtable and cteList.
2152 : */
8227 tgl 2153 CBC 260626 : if (parsetree->hasSubLinks)
7348 2154 17322 : query_tree_walker(parsetree, fireRIRonSubLink, (void *) activeRIRs,
5300 tgl 2155 ECB : QTW_IGNORE_RC_SUBQUERIES);
8955 bruce 2156 :
2157 : /*
718 peter 2158 : * Apply any row-level security policies. We do this last because it
2159 : * requires special recursion detection if the new quals have sublink
2160 : * subqueries, and if we did it in the loop above query_tree_walker would
2161 : * then recurse into those quals a second time.
2162 : */
2909 sfrost 2163 CBC 260626 : rt_index = 0;
2909 sfrost 2164 GIC 541283 : foreach(lc, parsetree->rtable)
2165 : {
2166 280738 : RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
2909 sfrost 2167 ECB : Relation rel;
2168 : List *securityQuals;
2169 : List *withCheckOptions;
2170 : bool hasRowSecurity;
2171 : bool hasSubLinks;
2172 :
2909 sfrost 2173 GIC 280738 : ++rt_index;
2174 :
2175 : /* Only normal relations can have RLS policies */
2176 280738 : if (rte->rtekind != RTE_RELATION ||
2128 mail 2177 CBC 198228 : (rte->relkind != RELKIND_RELATION &&
2126 tgl 2178 11575 : rte->relkind != RELKIND_PARTITIONED_TABLE))
2909 sfrost 2179 GIC 86484 : continue;
2180 :
1539 andres 2181 194254 : rel = table_open(rte->relid, NoLock);
2182 :
2909 sfrost 2183 ECB : /*
2184 : * Fetch any new security quals that must be applied to this RTE.
2185 : */
2763 sfrost 2186 GIC 194254 : get_row_security_policies(parsetree, rte, rt_index,
2187 : &securityQuals, &withCheckOptions,
2188 : &hasRowSecurity, &hasSubLinks);
2189 :
2909 2190 194230 : if (securityQuals != NIL || withCheckOptions != NIL)
2191 : {
2192 1185 : if (hasSubLinks)
2909 sfrost 2193 ECB : {
2781 2194 : acquireLocksOnSubLinks_context context;
2195 :
2196 : /*
2197 : * Recursively process the new quals, checking for infinite
2198 : * recursion.
2199 : */
2909 sfrost 2200 GIC 309 : if (list_member_oid(activeRIRs, RelationGetRelid(rel)))
2201 21 : ereport(ERROR,
2909 sfrost 2202 ECB : (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
2203 : errmsg("infinite recursion detected in policy for relation \"%s\"",
2204 : RelationGetRelationName(rel))));
2205 :
1362 tgl 2206 GIC 288 : activeRIRs = lappend_oid(activeRIRs, RelationGetRelid(rel));
2207 :
2781 sfrost 2208 ECB : /*
2209 : * get_row_security_policies just passed back securityQuals
2210 : * and/or withCheckOptions, and there were SubLinks, make sure
2211 : * we lock any relations which are referenced.
2212 : *
2213 : * These locks would normally be acquired by the parser, but
2214 : * securityQuals and withCheckOptions are added post-parsing.
2215 : */
2781 sfrost 2216 GIC 288 : context.for_execute = true;
2781 sfrost 2217 CBC 288 : (void) acquireLocksOnSubLinks((Node *) securityQuals, &context);
2218 288 : (void) acquireLocksOnSubLinks((Node *) withCheckOptions,
2219 : &context);
2781 sfrost 2220 ECB :
2221 : /*
2222 : * Now that we have the locks on anything added by
2223 : * get_row_security_policies, fire any RIR rules for them.
2224 : */
2878 bruce 2225 GIC 288 : expression_tree_walker((Node *) securityQuals,
2226 : fireRIRonSubLink, (void *) activeRIRs);
2227 :
2878 bruce 2228 CBC 255 : expression_tree_walker((Node *) withCheckOptions,
2878 bruce 2229 ECB : fireRIRonSubLink, (void *) activeRIRs);
2909 sfrost 2230 :
1362 tgl 2231 CBC 252 : activeRIRs = list_delete_last(activeRIRs);
2232 : }
2909 sfrost 2233 ECB :
2234 : /*
2235 : * Add the new security barrier quals to the start of the RTE's
2341 tgl 2236 : * list so that they get applied before any existing barrier quals
2237 : * (which would have come from a security-barrier view, and should
2238 : * get lower priority than RLS conditions on the table itself).
2239 : */
2909 sfrost 2240 GIC 2256 : rte->securityQuals = list_concat(securityQuals,
2241 1128 : rte->securityQuals);
2242 :
2243 1128 : parsetree->withCheckOptions = list_concat(withCheckOptions,
2118 tgl 2244 1128 : parsetree->withCheckOptions);
2245 : }
2246 :
2247 : /*
2248 : * Make sure the query is marked correctly if row-level security
2249 : * applies, or if the new quals had sublinks.
2250 : */
2909 sfrost 2251 194173 : if (hasRowSecurity)
2252 1388 : parsetree->hasRowSecurity = true;
2253 194173 : if (hasSubLinks)
2909 sfrost 2254 CBC 252 : parsetree->hasSubLinks = true;
2255 :
1539 andres 2256 GIC 194173 : table_close(rel, NoLock);
2257 : }
2258 :
8955 bruce 2259 260545 : return parsetree;
8955 bruce 2260 ECB : }
2261 :
2262 :
8160 tgl 2263 : /*
2264 : * Modify the given query by adding 'AND rule_qual IS NOT TRUE' to its
2265 : * qualification. This is used to generate suitable "else clauses" for
2266 : * conditional INSTEAD rules. (Unfortunately we must use "x IS NOT TRUE",
2267 : * not just "NOT x" which the planner is much smarter about, else we will
2268 : * do the wrong thing when the qual evaluates to NULL.)
2269 : *
2270 : * The rule_qual may contain references to OLD or NEW. OLD references are
2271 : * replaced by references to the specified rt_index (the relation that the
2272 : * rule applies to). NEW references are only possible for INSERT and UPDATE
2273 : * queries on the relation itself, and so they should be replaced by copies
2274 : * of the related entries in the query's own targetlist.
2275 : */
9344 bruce 2276 : static Query *
7476 tgl 2277 CBC 222 : CopyAndAddInvertedQual(Query *parsetree,
2278 : Node *rule_qual,
2279 : int rt_index,
7476 tgl 2280 ECB : CmdType event)
2281 : {
2282 : /* Don't scribble on the passed qual (it's in the relcache!) */
2222 peter_e 2283 GIC 222 : Node *new_qual = copyObject(rule_qual);
2284 : acquireLocksOnSubLinks_context context;
2285 :
3321 tgl 2286 222 : context.for_execute = true;
2287 :
2288 : /*
6519 tgl 2289 ECB : * In case there are subqueries in the qual, acquire necessary locks and
2290 : * fix any deleted JOIN RTE entries. (This is somewhat redundant with
6385 bruce 2291 : * rewriteRuleAction, but not entirely ... consider restructuring so that
2292 : * we only need to process the qual this way once.)
2293 : */
3321 tgl 2294 GIC 222 : (void) acquireLocksOnSubLinks(new_qual, &context);
2295 :
2296 : /* Fix references to OLD */
8160 2297 222 : ChangeVarNodes(new_qual, PRS2_OLD_VARNO, rt_index, 0);
2298 : /* Fix references to NEW */
2299 222 : if (event == CMD_INSERT || event == CMD_UPDATE)
3804 2300 432 : new_qual = ReplaceVarsFromTargetList(new_qual,
2301 : PRS2_NEW_VARNO,
2302 : 0,
2303 216 : rt_fetch(rt_index,
2304 : parsetree->rtable),
2305 : parsetree->targetList,
2306 : (event == CMD_UPDATE) ?
2307 : REPLACEVARS_CHANGE_VARNO :
2308 : REPLACEVARS_SUBSTITUTE_NULL,
2309 : rt_index,
2310 : &parsetree->hasSubLinks);
2311 : /* And attach the fixed qual */
6519 2312 222 : AddInvertedQual(parsetree, new_qual);
2313 :
2314 222 : return parsetree;
2315 : }
2316 :
2317 :
2318 : /*
2319 : * fireRules -
2320 : * Iterate through rule locks applying rules.
2321 : *
2322 : * Input arguments:
2323 : * parsetree - original query
7477 tgl 2324 ECB : * rt_index - RT index of result relation in original query
2325 : * event - type of rule event
2326 : * locks - list of rules to fire
2327 : * Output arguments:
2328 : * *instead_flag - set true if any unqualified INSTEAD rule is found
2329 : * (must be initialized to false)
2330 : * *returning_flag - set true if we rewrite RETURNING clause in any rule
2331 : * (must be initialized to false)
2332 : * *qual_product - filled with modified original query if any qualified
2333 : * INSTEAD rule is found (must be initialized to NULL)
2334 : * Return value:
2335 : * list of rule actions adjusted for use with this query
2336 : *
2337 : * Qualified INSTEAD rules generate their action with the qualification
2338 : * condition added. They also generate a modified version of the original
2339 : * query with the negated qualification added, so that it will run only for
2340 : * rows that the qualified action doesn't act on. (If there are multiple
2341 : * qualified INSTEAD rules, we AND all the negated quals onto a single
2342 : * modified original query.) We won't execute the original, unmodified
2343 : * query if we find either qualified or unqualified INSTEAD rules. If
2344 : * we find both, the modified original query is discarded too.
2345 : */
9344 bruce 2346 : static List *
9344 bruce 2347 CBC 53508 : fireRules(Query *parsetree,
2348 : int rt_index,
2349 : CmdType event,
9344 bruce 2350 ECB : List *locks,
7477 tgl 2351 : bool *instead_flag,
2352 : bool *returning_flag,
2353 : Query **qual_product)
2354 : {
9344 bruce 2355 CBC 53508 : List *results = NIL;
2356 : ListCell *l;
9345 bruce 2357 ECB :
6892 neilc 2358 GIC 54249 : foreach(l, locks)
2359 : {
2360 744 : RewriteRule *rule_lock = (RewriteRule *) lfirst(l);
7477 tgl 2361 744 : Node *event_qual = rule_lock->qual;
2362 744 : List *actions = rule_lock->actions;
2363 : QuerySource qsrc;
2364 : ListCell *r;
2365 :
2366 : /* Determine correct QuerySource value for actions */
7482 2367 744 : if (rule_lock->isInstead)
2368 : {
2369 552 : if (event_qual != NULL)
2370 225 : qsrc = QSRC_QUAL_INSTEAD_RULE;
7482 tgl 2371 ECB : else
2372 : {
7482 tgl 2373 CBC 327 : qsrc = QSRC_INSTEAD_RULE;
7188 bruce 2374 327 : *instead_flag = true; /* report unqualified INSTEAD */
7477 tgl 2375 ECB : }
2376 : }
2377 : else
7482 tgl 2378 GIC 192 : qsrc = QSRC_NON_INSTEAD_RULE;
2379 :
2380 744 : if (qsrc == QSRC_QUAL_INSTEAD_RULE)
2381 : {
2382 : /*
6385 bruce 2383 ECB : * If there are INSTEAD rules with qualifications, the original
2384 : * query is still performed. But all the negated rule
2385 : * qualifications of the INSTEAD rules are added so it does its
2386 : * actions only in cases where the rule quals of all INSTEAD rules
2387 : * are false. Think of it as the default action in a case. We save
2388 : * this in *qual_product so RewriteQuery() can add it to the query
2389 : * list after we mangled it up enough.
7477 tgl 2390 : *
2391 : * If we have already found an unqualified INSTEAD rule, then
2392 : * *qual_product won't be used, so don't bother building it.
2393 : */
7188 bruce 2394 CBC 225 : if (!*instead_flag)
7477 tgl 2395 ECB : {
7477 tgl 2396 GIC 222 : if (*qual_product == NULL)
6519 tgl 2397 CBC 180 : *qual_product = copyObject(parsetree);
7476 tgl 2398 GIC 222 : *qual_product = CopyAndAddInvertedQual(*qual_product,
2399 : event_qual,
2400 : rt_index,
7476 tgl 2401 ECB : event);
2402 : }
2403 : }
2404 :
2405 : /* Now process the rule's actions and add them to the result list */
9345 bruce 2406 GIC 1512 : foreach(r, actions)
2407 : {
9344 2408 771 : Query *rule_action = lfirst(r);
2409 :
9000 scrappy 2410 771 : if (rule_action->commandType == CMD_NOTHING)
2411 105 : continue;
2412 :
7970 tgl 2413 666 : rule_action = rewriteRuleAction(parsetree, rule_action,
2414 : event_qual, rt_index, event,
6063 tgl 2415 ECB : returning_flag);
2416 :
7482 tgl 2417 GIC 663 : rule_action->querySource = qsrc;
2118 2418 663 : rule_action->canSetTag = false; /* might change later */
7482 tgl 2419 ECB :
7970 tgl 2420 GIC 663 : results = lappend(results, rule_action);
9345 bruce 2421 ECB : }
2422 : }
7482 tgl 2423 :
9345 bruce 2424 GIC 53505 : return results;
9770 scrappy 2425 ECB : }
2426 :
2427 :
3774 tgl 2428 : /*
3774 tgl 2429 EUB : * get_view_query - get the Query from a view's _RETURN rule.
2430 : *
3774 tgl 2431 ECB : * Caller should have verified that the relation is a view, and therefore
2432 : * we should find an ON SELECT action.
2433 : *
2434 : * Note that the pointer returned is into the relcache and therefore must
2666 sfrost 2435 EUB : * be treated as read-only to the caller and not modified or scribbled on.
2436 : */
2437 : Query *
3774 tgl 2438 GIC 2369 : get_view_query(Relation view)
2439 : {
2440 : int i;
2441 :
2442 2369 : Assert(view->rd_rel->relkind == RELKIND_VIEW);
2443 :
2444 2369 : for (i = 0; i < view->rd_rules->numLocks; i++)
2445 : {
2446 2369 : RewriteRule *rule = view->rd_rules->rules[i];
2447 :
3774 tgl 2448 CBC 2369 : if (rule->event == CMD_SELECT)
2449 : {
3774 tgl 2450 ECB : /* A _RETURN rule should have only one action */
3774 tgl 2451 GIC 2369 : if (list_length(rule->actions) != 1)
3774 tgl 2452 LBC 0 : elog(ERROR, "invalid _RETURN rule action specification");
2453 :
3774 tgl 2454 CBC 2369 : return (Query *) linitial(rule->actions);
3774 tgl 2455 ECB : }
2456 : }
2457 :
3774 tgl 2458 LBC 0 : elog(ERROR, "failed to find _RETURN rule for view");
3774 tgl 2459 ECB : return NULL; /* keep compiler quiet */
2460 : }
2461 :
2462 :
2463 : /*
2464 : * view_has_instead_trigger - does view have an INSTEAD OF trigger for event?
2465 : *
3774 tgl 2466 EUB : * If it does, we don't want to treat it as auto-updatable. This test can't
3460 rhaas 2467 : * be folded into view_query_is_auto_updatable because it's not an error
2468 : * condition.
2469 : */
3774 tgl 2470 ECB : static bool
3774 tgl 2471 GIC 1456 : view_has_instead_trigger(Relation view, CmdType event)
2472 : {
2473 1456 : TriggerDesc *trigDesc = view->trigdesc;
2474 :
2475 1456 : switch (event)
2476 : {
2477 672 : case CMD_INSERT:
2478 672 : if (trigDesc && trigDesc->trig_insert_instead_row)
2479 66 : return true;
2480 606 : break;
2481 586 : case CMD_UPDATE:
2482 586 : if (trigDesc && trigDesc->trig_update_instead_row)
2483 69 : return true;
2484 517 : break;
2485 198 : case CMD_DELETE:
3774 tgl 2486 CBC 198 : if (trigDesc && trigDesc->trig_delete_instead_row)
3774 tgl 2487 GIC 27 : return true;
3774 tgl 2488 CBC 171 : break;
3774 tgl 2489 UIC 0 : default:
2490 0 : elog(ERROR, "unrecognized CmdType: %d", (int) event);
2491 : break;
2492 : }
3774 tgl 2493 GIC 1294 : return false;
2494 : }
2495 :
2496 :
2497 : /*
2498 : * view_col_is_auto_updatable - test whether the specified column of a view
3460 rhaas 2499 ECB : * is auto-updatable. Returns NULL (if the column can be updated) or a message
2500 : * string giving the reason that it cannot be.
2501 : *
1692 michael 2502 : * The returned string has not been translated; if it is shown as an error
2503 : * message, the caller should apply _() to translate it.
2504 : *
3460 rhaas 2505 : * Note that the checks performed here are local to this view. We do not check
2506 : * whether the referenced column of the underlying base relation is updatable.
3774 tgl 2507 : */
3460 rhaas 2508 : static const char *
3460 rhaas 2509 GIC 4995 : view_col_is_auto_updatable(RangeTblRef *rtr, TargetEntry *tle)
3774 tgl 2510 ECB : {
3460 rhaas 2511 GBC 4995 : Var *var = (Var *) tle->expr;
2512 :
3460 rhaas 2513 ECB : /*
2514 : * For now, the only updatable columns we support are those that are Vars
2515 : * referring to user columns of the underlying base relation.
2516 : *
2517 : * The view targetlist may contain resjunk columns (e.g., a view defined
2518 : * like "SELECT * FROM t ORDER BY a+b" is auto-updatable) but such columns
2519 : * are not auto-updatable, and in fact should never appear in the outer
2520 : * query's targetlist.
2521 : */
3460 rhaas 2522 GIC 4995 : if (tle->resjunk)
2523 90 : return gettext_noop("Junk view columns are not updatable.");
2524 :
2525 4905 : if (!IsA(var, Var) ||
2526 4506 : var->varno != rtr->rtindex ||
2527 4506 : var->varlevelsup != 0)
2528 399 : return gettext_noop("View columns that are not columns of their base relation are not updatable.");
2529 :
2530 4506 : if (var->varattno < 0)
2531 177 : return gettext_noop("View columns that refer to system columns are not updatable.");
2532 :
2533 4329 : if (var->varattno == 0)
3460 rhaas 2534 LBC 0 : return gettext_noop("View columns that return whole-row references are not updatable.");
2535 :
3460 rhaas 2536 GIC 4329 : return NULL; /* the view column is updatable */
2537 : }
2538 :
2539 :
2540 : /*
2541 : * view_query_is_auto_updatable - test whether the specified view definition
2542 : * represents an auto-updatable view. Returns NULL (if the view can be updated)
2543 : * or a message string giving the reason that it cannot be.
2544 :
2545 : * The returned string has not been translated; if it is shown as an error
2546 : * message, the caller should apply _() to translate it.
2547 : *
2548 : * If check_cols is true, the view is required to have at least one updatable
2549 : * column (necessary for INSERT/UPDATE). Otherwise the view's columns are not
2550 : * checked for updatability. See also view_cols_are_auto_updatable.
2551 : *
2552 : * Note that the checks performed here are only based on the view definition.
2553 : * We do not check whether any base relations referred to by the view are
2554 : * updatable.
2555 : */
2556 : const char *
3284 sfrost 2557 2258 : view_query_is_auto_updatable(Query *viewquery, bool check_cols)
2558 : {
2559 : RangeTblRef *rtr;
2560 : RangeTblEntry *base_rte;
2561 :
2562 : /*----------
2563 : * Check if the view is simply updatable. According to SQL-92 this means:
2564 : * - No DISTINCT clause.
2565 : * - Each TLE is a column reference, and each column appears at most once.
2566 : * - FROM contains exactly one base relation.
2567 : * - No GROUP BY or HAVING clauses.
2568 : * - No set operations (UNION, INTERSECT or EXCEPT).
2569 : * - No sub-queries in the WHERE clause that reference the target table.
2570 : *
3774 tgl 2571 ECB : * We ignore that last restriction since it would be complex to enforce
2572 : * and there isn't any actual benefit to disallowing sub-queries. (The
2573 : * semantic issues that the standard is presumably concerned about don't
2574 : * arise in Postgres, since any such sub-query will not see any updates
2575 : * executed by the outer query anyway, thanks to MVCC snapshotting.)
2576 : *
3460 rhaas 2577 : * We also relax the second restriction by supporting part of SQL:1999
2578 : * feature T111, which allows for a mix of updatable and non-updatable
2579 : * columns, provided that an INSERT or UPDATE doesn't attempt to assign to
2580 : * a non-updatable column.
2581 : *
2582 : * In addition we impose these constraints, involving features that are
3774 tgl 2583 : * not part of SQL-92:
2584 : * - No CTEs (WITH clauses).
2585 : * - No OFFSET or LIMIT clauses (this matches a SQL:2008 restriction).
2586 : * - No system columns (including whole-row references) in the tlist.
3460 rhaas 2587 : * - No window functions in the tlist.
2588 : * - No set-returning functions in the tlist.
2589 : *
2590 : * Note that we do these checks without recursively expanding the view.
2591 : * If the base relation is a view, we'll recursively deal with it later.
2592 : *----------
2593 : */
3774 tgl 2594 GIC 2258 : if (viewquery->distinctClause != NIL)
2595 36 : return gettext_noop("Views containing DISTINCT are not automatically updatable.");
2596 :
2885 andres 2597 2222 : if (viewquery->groupClause != NIL || viewquery->groupingSets)
3774 tgl 2598 CBC 18 : return gettext_noop("Views containing GROUP BY are not automatically updatable.");
3774 tgl 2599 ECB :
3774 tgl 2600 GIC 2204 : if (viewquery->havingQual != NULL)
3774 tgl 2601 CBC 15 : return gettext_noop("Views containing HAVING are not automatically updatable.");
3774 tgl 2602 ECB :
3774 tgl 2603 GIC 2189 : if (viewquery->setOperations != NULL)
3647 peter_e 2604 CBC 18 : return gettext_noop("Views containing UNION, INTERSECT, or EXCEPT are not automatically updatable.");
3774 tgl 2605 ECB :
3774 tgl 2606 GIC 2171 : if (viewquery->cteList != NIL)
2607 18 : return gettext_noop("Views containing WITH are not automatically updatable.");
2608 :
2609 2153 : if (viewquery->limitOffset != NULL || viewquery->limitCount != NULL)
2610 246 : return gettext_noop("Views containing LIMIT or OFFSET are not automatically updatable.");
3774 tgl 2611 ECB :
3460 rhaas 2612 : /*
2613 : * We must not allow window functions or set returning functions in the
2614 : * targetlist. Otherwise we might end up inserting them into the quals of
2615 : * the main query. We must also check for aggregates in the targetlist in
3460 rhaas 2616 EUB : * case they appear without a GROUP BY.
2617 : *
3460 rhaas 2618 ECB : * These restrictions ensure that each row of the view corresponds to a
2619 : * unique row in the underlying base relation.
2620 : */
3460 rhaas 2621 CBC 1907 : if (viewquery->hasAggs)
3145 peter_e 2622 15 : return gettext_noop("Views that return aggregate functions are not automatically updatable.");
3460 rhaas 2623 ECB :
3460 rhaas 2624 CBC 1892 : if (viewquery->hasWindowFuncs)
3145 peter_e 2625 GIC 18 : return gettext_noop("Views that return window functions are not automatically updatable.");
3460 rhaas 2626 ECB :
2399 tgl 2627 CBC 1874 : if (viewquery->hasTargetSRFs)
3460 rhaas 2628 GIC 21 : return gettext_noop("Views that return set-returning functions are not automatically updatable.");
2629 :
2630 : /*
2631 : * The view query should select from a single base relation, which must be
2632 : * a table or another view.
3774 tgl 2633 ECB : */
3774 tgl 2634 GIC 1853 : if (list_length(viewquery->jointree->fromlist) != 1)
2635 33 : return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
2636 :
2637 1820 : rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist);
3774 tgl 2638 CBC 1820 : if (!IsA(rtr, RangeTblRef))
3774 tgl 2639 LBC 0 : return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
2640 :
3774 tgl 2641 CBC 1820 : base_rte = rt_fetch(rtr->rtindex, viewquery->rtable);
3774 tgl 2642 GIC 1820 : if (base_rte->rtekind != RTE_RELATION ||
3774 tgl 2643 CBC 1772 : (base_rte->relkind != RELKIND_RELATION &&
3588 tgl 2644 GIC 676 : base_rte->relkind != RELKIND_FOREIGN_TABLE &&
2266 rhaas 2645 CBC 665 : base_rte->relkind != RELKIND_VIEW &&
2646 86 : base_rte->relkind != RELKIND_PARTITIONED_TABLE))
3774 tgl 2647 GIC 69 : return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
2648 :
2886 simon 2649 1751 : if (base_rte->tablesample)
2886 simon 2650 CBC 3 : return gettext_noop("Views containing TABLESAMPLE are not automatically updatable.");
2886 simon 2651 EUB :
2652 : /*
2653 : * Check that the view has at least one updatable column. This is required
3460 rhaas 2654 ECB : * for INSERT/UPDATE but not for DELETE.
2655 : */
3460 rhaas 2656 GIC 1748 : if (check_cols)
2657 : {
2658 : ListCell *cell;
2659 : bool found;
2660 :
2661 1118 : found = false;
2662 1196 : foreach(cell, viewquery->targetList)
2663 : {
2664 1196 : TargetEntry *tle = (TargetEntry *) lfirst(cell);
2665 :
2666 1196 : if (view_col_is_auto_updatable(rtr, tle) == NULL)
2667 : {
2668 1118 : found = true;
2669 1118 : break;
2670 : }
2671 : }
2672 :
2673 1118 : if (!found)
3460 rhaas 2674 UIC 0 : return gettext_noop("Views that have no updatable columns are not automatically updatable.");
2675 : }
2676 :
3460 rhaas 2677 GIC 1748 : return NULL; /* the view is updatable */
2678 : }
2679 :
2680 :
2681 : /*
3460 rhaas 2682 ECB : * view_cols_are_auto_updatable - test whether all of the required columns of
2683 : * an auto-updatable view are actually updatable. Returns NULL (if all the
2684 : * required columns can be updated) or a message string giving the reason that
2685 : * they cannot be.
2686 : *
2687 : * The returned string has not been translated; if it is shown as an error
2688 : * message, the caller should apply _() to translate it.
2689 : *
2690 : * This should be used for INSERT/UPDATE to ensure that we don't attempt to
2691 : * assign to any non-updatable columns.
2692 : *
2693 : * Additionally it may be used to retrieve the set of updatable columns in the
2694 : * view, or if one or more of the required columns is not updatable, the name
2695 : * of the first offending non-updatable column.
2696 : *
2697 : * The caller must have already verified that this is an auto-updatable view
2698 : * using view_query_is_auto_updatable.
2699 : *
2700 : * Note that the checks performed here are only based on the view definition.
2701 : * We do not check whether the referenced columns of the base relation are
2702 : * updatable.
2703 : */
2704 : static const char *
3460 rhaas 2705 CBC 1528 : view_cols_are_auto_updatable(Query *viewquery,
3460 rhaas 2706 ECB : Bitmapset *required_cols,
2707 : Bitmapset **updatable_cols,
2708 : char **non_updatable_col)
2709 : {
2710 : RangeTblRef *rtr;
2711 : AttrNumber col;
2712 : ListCell *cell;
2713 :
2714 : /*
2715 : * The caller should have verified that this view is auto-updatable and so
2716 : * there should be a single base relation.
2717 : */
3460 rhaas 2718 CBC 1528 : Assert(list_length(viewquery->jointree->fromlist) == 1);
2190 tgl 2719 GIC 1528 : rtr = linitial_node(RangeTblRef, viewquery->jointree->fromlist);
3460 rhaas 2720 ECB :
2721 : /* Initialize the optional return values */
3460 rhaas 2722 GIC 1528 : if (updatable_cols != NULL)
3460 rhaas 2723 CBC 483 : *updatable_cols = NULL;
2724 1528 : if (non_updatable_col != NULL)
2725 1045 : *non_updatable_col = NULL;
2726 :
2727 : /* Test each view column for updatability */
3460 rhaas 2728 GIC 1528 : col = -FirstLowInvalidHeapAttributeNumber;
3460 rhaas 2729 CBC 5273 : foreach(cell, viewquery->targetList)
2730 : {
3460 rhaas 2731 GIC 3799 : TargetEntry *tle = (TargetEntry *) lfirst(cell);
2732 : const char *col_update_detail;
2733 :
2734 3799 : col++;
2735 3799 : col_update_detail = view_col_is_auto_updatable(rtr, tle);
2736 :
2737 3799 : if (col_update_detail == NULL)
2738 : {
2739 : /* The column is updatable */
2740 3211 : if (updatable_cols != NULL)
2741 879 : *updatable_cols = bms_add_member(*updatable_cols, col);
2742 : }
2743 588 : else if (bms_is_member(col, required_cols))
2744 : {
2745 : /* The required column is not updatable */
2746 54 : if (non_updatable_col != NULL)
2747 54 : *non_updatable_col = tle->resname;
2748 54 : return col_update_detail;
2749 : }
2750 : }
2751 :
3260 bruce 2752 1474 : return NULL; /* all the required view columns are updatable */
2753 : }
2754 :
2755 :
2756 : /*
2757 : * relation_is_updatable - determine which update events the specified
2758 : * relation supports.
2759 : *
2760 : * Note that views may contain a mix of updatable and non-updatable columns.
2761 : * For a view to support INSERT/UPDATE it must have at least one updatable
2762 : * column, but there is no such restriction for DELETE. If include_cols is
2763 : * non-NULL, then only the specified columns are considered when testing for
2764 : * updatability.
3460 rhaas 2765 ECB : *
2766 : * Unlike the preceding functions, this does recurse to look at a view's
2767 : * base relations, so it needs to detect recursion. To do that, we pass
2768 : * a list of currently-considered outer relations. External callers need
2769 : * only pass NIL.
1235 tgl 2770 : *
2771 : * This is used for the information_schema views, which have separate concepts
2772 : * of "updatable" and "trigger updatable". A relation is "updatable" if it
2773 : * can be updated without the need for triggers (either because it has a
2774 : * suitable RULE, or because it is simple enough to be automatically updated).
2775 : * A relation is "trigger updatable" if it has a suitable INSTEAD OF trigger.
2776 : * The SQL standard regards this as not necessarily updatable, presumably
3774 2777 : * because there is no way of knowing what the trigger will actually do.
2778 : * The information_schema views therefore call this function with
3588 2779 : * include_triggers = false. However, other callers might only care whether
2780 : * data-modifying SQL will work, so they can pass include_triggers = true
2781 : * to have trigger updatability included in the result.
2782 : *
2783 : * The return value is a bitmask of rule event numbers indicating which of
2784 : * the INSERT, UPDATE and DELETE operations are supported. (We do it this way
2785 : * so that we can test for UPDATE plus DELETE support in a single call.)
2786 : */
2787 : int
3460 rhaas 2788 GBC 978 : relation_is_updatable(Oid reloid,
2789 : List *outer_reloids,
2790 : bool include_triggers,
3460 rhaas 2791 ECB : Bitmapset *include_cols)
2792 : {
3588 tgl 2793 GBC 978 : int events = 0;
3774 tgl 2794 EUB : Relation rel;
2795 : RuleLock *rulelocks;
2796 :
2797 : #define ALL_EVENTS ((1 << CMD_INSERT) | (1 << CMD_UPDATE) | (1 << CMD_DELETE))
3588 tgl 2798 ECB :
1235 2799 : /* Since this function recurses, it could be driven to stack overflow */
1235 tgl 2800 GIC 978 : check_stack_depth();
1235 tgl 2801 ECB :
3774 tgl 2802 CBC 978 : rel = try_relation_open(reloid, AccessShareLock);
2803 :
2804 : /*
2805 : * If the relation doesn't exist, return zero rather than throwing an
3602 bruce 2806 ECB : * error. This is helpful since scanning an information_schema view under
3568 rhaas 2807 : * MVCC rules can result in referencing rels that have actually been
2808 : * deleted already.
2809 : */
3774 tgl 2810 GIC 978 : if (rel == NULL)
3588 tgl 2811 LBC 0 : return 0;
2812 :
1235 tgl 2813 ECB : /* If we detect a recursive view, report that it is not updatable */
1235 tgl 2814 CBC 978 : if (list_member_oid(outer_reloids, RelationGetRelid(rel)))
2815 : {
1235 tgl 2816 LBC 0 : relation_close(rel, AccessShareLock);
1235 tgl 2817 UIC 0 : return 0;
2818 : }
2819 :
2820 : /* If the relation is a table, it is always updatable */
2126 dean.a.rasheed 2821 CBC 978 : if (rel->rd_rel->relkind == RELKIND_RELATION ||
2126 dean.a.rasheed 2822 GIC 978 : rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
3588 tgl 2823 ECB : {
3588 tgl 2824 CBC 9 : relation_close(rel, AccessShareLock);
3588 tgl 2825 GIC 9 : return ALL_EVENTS;
2826 : }
2827 :
2828 : /* Look for unconditional DO INSTEAD rules, and note supported events */
3774 tgl 2829 CBC 969 : rulelocks = rel->rd_rules;
3774 tgl 2830 GIC 969 : if (rulelocks != NULL)
3774 tgl 2831 EUB : {
2832 : int i;
2833 :
3774 tgl 2834 GIC 2124 : for (i = 0; i < rulelocks->numLocks; i++)
3774 tgl 2835 EUB : {
3774 tgl 2836 GBC 1155 : if (rulelocks->rules[i]->isInstead &&
2837 1149 : rulelocks->rules[i]->qual == NULL)
3774 tgl 2838 EUB : {
3588 tgl 2839 GBC 1149 : events |= ((1 << rulelocks->rules[i]->event) & ALL_EVENTS);
3774 tgl 2840 EUB : }
2841 : }
2842 :
3588 2843 : /* If we have rules for all events, we're done */
3588 tgl 2844 GIC 969 : if (events == ALL_EVENTS)
3774 tgl 2845 EUB : {
3774 tgl 2846 GBC 30 : relation_close(rel, AccessShareLock);
3588 tgl 2847 GIC 30 : return events;
2848 : }
2849 : }
2850 :
2851 : /* Similarly look for INSTEAD OF triggers, if they are to be included */
3588 tgl 2852 CBC 939 : if (include_triggers)
2853 : {
3588 tgl 2854 UBC 0 : TriggerDesc *trigDesc = rel->trigdesc;
2855 :
2856 0 : if (trigDesc)
3588 tgl 2857 EUB : {
3588 tgl 2858 UIC 0 : if (trigDesc->trig_insert_instead_row)
2859 0 : events |= (1 << CMD_INSERT);
2860 0 : if (trigDesc->trig_update_instead_row)
3588 tgl 2861 UBC 0 : events |= (1 << CMD_UPDATE);
2862 0 : if (trigDesc->trig_delete_instead_row)
2863 0 : events |= (1 << CMD_DELETE);
3588 tgl 2864 EUB :
2865 : /* If we have triggers for all events, we're done */
3588 tgl 2866 UBC 0 : if (events == ALL_EVENTS)
2867 : {
3588 tgl 2868 UIC 0 : relation_close(rel, AccessShareLock);
3588 tgl 2869 UBC 0 : return events;
3588 tgl 2870 EUB : }
2871 : }
2872 : }
2873 :
3588 tgl 2874 ECB : /* If this is a foreign table, check which update events it supports */
3588 tgl 2875 GIC 939 : if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
3588 tgl 2876 ECB : {
3588 tgl 2877 UIC 0 : FdwRoutine *fdwroutine = GetFdwRoutineForRelation(rel, false);
3588 tgl 2878 ECB :
3588 tgl 2879 UIC 0 : if (fdwroutine->IsForeignRelUpdatable != NULL)
2880 0 : events |= fdwroutine->IsForeignRelUpdatable(rel);
2881 : else
2882 : {
2883 : /* Assume presence of executor functions is sufficient */
2884 0 : if (fdwroutine->ExecForeignInsert != NULL)
2885 0 : events |= (1 << CMD_INSERT);
2886 0 : if (fdwroutine->ExecForeignUpdate != NULL)
2887 0 : events |= (1 << CMD_UPDATE);
2888 0 : if (fdwroutine->ExecForeignDelete != NULL)
2889 0 : events |= (1 << CMD_DELETE);
2890 : }
2891 :
3588 tgl 2892 LBC 0 : relation_close(rel, AccessShareLock);
3588 tgl 2893 UIC 0 : return events;
2894 : }
3774 tgl 2895 ECB :
2896 : /* Check if this is an automatically updatable view */
3460 rhaas 2897 GIC 939 : if (rel->rd_rel->relkind == RELKIND_VIEW)
3774 tgl 2898 ECB : {
3460 rhaas 2899 CBC 939 : Query *viewquery = get_view_query(rel);
2900 :
3284 sfrost 2901 939 : if (view_query_is_auto_updatable(viewquery, false) == NULL)
2902 : {
2903 : Bitmapset *updatable_cols;
2904 : int auto_events;
2905 : RangeTblRef *rtr;
2906 : RangeTblEntry *base_rte;
2907 : Oid baseoid;
2908 :
3460 rhaas 2909 ECB : /*
2910 : * Determine which of the view's columns are updatable. If there
3260 bruce 2911 : * are none within the set of columns we are looking at, then the
2912 : * view doesn't support INSERT/UPDATE, but it may still support
2913 : * DELETE.
3460 rhaas 2914 : */
3460 rhaas 2915 GIC 483 : view_cols_are_auto_updatable(viewquery, NULL,
3460 rhaas 2916 ECB : &updatable_cols, NULL);
2917 :
3460 rhaas 2918 GIC 483 : if (include_cols != NULL)
3460 rhaas 2919 CBC 249 : updatable_cols = bms_int_members(updatable_cols, include_cols);
2920 :
2921 483 : if (bms_is_empty(updatable_cols))
2118 tgl 2922 GIC 51 : auto_events = (1 << CMD_DELETE); /* May support DELETE */
2923 : else
2924 432 : auto_events = ALL_EVENTS; /* May support all events */
3460 rhaas 2925 ECB :
2926 : /*
2927 : * The base relation must also support these update commands.
2928 : * Tables are always updatable, but for any other kind of base
2929 : * relation we must do a recursive check limited to the columns
2930 : * referenced by the locally updatable columns in this view.
2931 : */
3460 rhaas 2932 CBC 483 : rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist);
2933 483 : base_rte = rt_fetch(rtr->rtindex, viewquery->rtable);
3460 rhaas 2934 GIC 483 : Assert(base_rte->rtekind == RTE_RELATION);
2935 :
2126 dean.a.rasheed 2936 483 : if (base_rte->relkind != RELKIND_RELATION &&
2937 261 : base_rte->relkind != RELKIND_PARTITIONED_TABLE)
2938 : {
3460 rhaas 2939 246 : baseoid = base_rte->relid;
1235 tgl 2940 246 : outer_reloids = lappend_oid(outer_reloids,
2941 : RelationGetRelid(rel));
3460 rhaas 2942 246 : include_cols = adjust_view_column_set(updatable_cols,
2943 : viewquery->targetList);
2944 246 : auto_events &= relation_is_updatable(baseoid,
2945 : outer_reloids,
3460 rhaas 2946 ECB : include_triggers,
2947 : include_cols);
1235 tgl 2948 CBC 246 : outer_reloids = list_delete_last(outer_reloids);
2949 : }
3460 rhaas 2950 GIC 483 : events |= auto_events;
3774 tgl 2951 ECB : }
2952 : }
2953 :
2954 : /* If we reach here, the relation may support some update commands */
3774 tgl 2955 CBC 939 : relation_close(rel, AccessShareLock);
3588 tgl 2956 GIC 939 : return events;
3774 tgl 2957 ECB : }
2958 :
2959 :
2960 : /*
2961 : * adjust_view_column_set - map a set of column numbers according to targetlist
2962 : *
2963 : * This is used with simply-updatable views to map column-permissions sets for
2964 : * the view columns onto the matching columns in the underlying base relation.
2965 : * The targetlist is expected to be a list of plain Vars of the underlying
2966 : * relation (as per the checks above in view_query_is_auto_updatable).
2967 : */
3774 tgl 2968 EUB : static Bitmapset *
3774 tgl 2969 GIC 2522 : adjust_view_column_set(Bitmapset *cols, List *targetlist)
3774 tgl 2970 EUB : {
3774 tgl 2971 GIC 2522 : Bitmapset *result = NULL;
2972 : int col;
3774 tgl 2973 EUB :
3054 tgl 2974 GBC 2522 : col = -1;
2975 4412 : while ((col = bms_next_member(cols, col)) >= 0)
3774 tgl 2976 EUB : {
2977 : /* bit numbers are offset by FirstLowInvalidHeapAttributeNumber */
3774 tgl 2978 GIC 1890 : AttrNumber attno = col + FirstLowInvalidHeapAttributeNumber;
2979 :
2980 1890 : if (attno == InvalidAttrNumber)
2981 : {
2982 : /*
2983 : * There's a whole-row reference to the view. For permissions
2984 : * purposes, treat it as a reference to each column available from
2985 : * the view. (We should *not* convert this to a whole-row
2986 : * reference to the base relation, since the view may not touch
3774 tgl 2987 ECB : * all columns of the base relation.)
2988 : */
2989 : ListCell *lc;
2990 :
3774 tgl 2991 LBC 0 : foreach(lc, targetlist)
2992 : {
2190 2993 0 : TargetEntry *tle = lfirst_node(TargetEntry, lc);
3774 tgl 2994 ECB : Var *var;
2995 :
3774 tgl 2996 UIC 0 : if (tle->resjunk)
3774 tgl 2997 UBC 0 : continue;
2238 peter_e 2998 UIC 0 : var = castNode(Var, tle->expr);
3774 tgl 2999 0 : result = bms_add_member(result,
2118 3000 0 : var->varattno - FirstLowInvalidHeapAttributeNumber);
3001 : }
3774 tgl 3002 ECB : }
3003 : else
3004 : {
3005 : /*
3006 : * Views do not have system columns, so we do not expect to see
3007 : * any other system attnos here. If we do find one, the error
3008 : * case will apply.
3009 : */
3774 tgl 3010 GIC 1890 : TargetEntry *tle = get_tle_by_resno(targetlist, attno);
3011 :
3012 1890 : if (tle != NULL && !tle->resjunk && IsA(tle->expr, Var))
3013 1890 : {
3014 1890 : Var *var = (Var *) tle->expr;
3015 :
3774 tgl 3016 CBC 1890 : result = bms_add_member(result,
2118 tgl 3017 GIC 1890 : var->varattno - FirstLowInvalidHeapAttributeNumber);
3018 : }
3019 : else
3774 tgl 3020 UIC 0 : elog(ERROR, "attribute number %d not found in view targetlist",
3021 : attno);
3022 : }
3023 : }
3024 :
3774 tgl 3025 GIC 2522 : return result;
3026 : }
3027 :
3028 :
3029 : /*
3030 : * rewriteTargetView -
3031 : * Attempt to rewrite a query where the target relation is a view, so that
3032 : * the view's base relation becomes the target relation.
3033 : *
3034 : * Note that the base relation here may itself be a view, which may or may not
3035 : * have INSTEAD OF triggers or rules to handle the update. That is handled by
3036 : * the recursion in RewriteQuery.
3037 : */
3038 : static Query *
3039 1246 : rewriteTargetView(Query *parsetree, Relation view)
3774 tgl 3040 ECB : {
3041 : Query *viewquery;
3042 : const char *auto_update_detail;
3043 : RangeTblRef *rtr;
3044 : int base_rt_index;
3045 : int new_rt_index;
3046 : RangeTblEntry *base_rte;
3047 : RangeTblEntry *view_rte;
3048 : RangeTblEntry *new_rte;
3049 : RTEPermissionInfo *base_perminfo;
3050 : RTEPermissionInfo *view_perminfo;
3051 : RTEPermissionInfo *new_perminfo;
3052 : Relation base_rel;
3053 : List *view_targetlist;
3054 : ListCell *lc;
3055 :
2666 sfrost 3056 : /*
3057 : * Get the Query from the view's ON SELECT rule. We're going to munge the
3058 : * Query to change the view's base relation into the target relation,
3059 : * along with various other changes along the way, so we need to make a
3060 : * copy of it (get_view_query() returns a pointer into the relcache, so we
3061 : * have to treat it as read-only).
3062 : */
2666 sfrost 3063 CBC 1246 : viewquery = copyObject(get_view_query(view));
3460 rhaas 3064 ECB :
3065 : /* The view must be updatable, else fail */
3066 : auto_update_detail =
3460 rhaas 3067 GIC 1246 : view_query_is_auto_updatable(viewquery,
3068 1246 : parsetree->commandType != CMD_DELETE);
3069 :
3774 tgl 3070 1246 : if (auto_update_detail)
3774 tgl 3071 ECB : {
3072 : /* messages here should match execMain.c's CheckValidResultRel */
3774 tgl 3073 GIC 54 : switch (parsetree->commandType)
3074 : {
3075 9 : case CMD_INSERT:
3076 9 : ereport(ERROR,
3077 : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
3078 : errmsg("cannot insert into view \"%s\"",
3774 tgl 3079 EUB : RelationGetRelationName(view)),
3080 : errdetail_internal("%s", _(auto_update_detail)),
3081 : errhint("To enable inserting into the view, provide an INSTEAD OF INSERT trigger or an unconditional ON INSERT DO INSTEAD rule.")));
3082 : break;
3774 tgl 3083 GIC 24 : case CMD_UPDATE:
3084 24 : ereport(ERROR,
3085 : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
3086 : errmsg("cannot update view \"%s\"",
3087 : RelationGetRelationName(view)),
3088 : errdetail_internal("%s", _(auto_update_detail)),
3089 : errhint("To enable updating the view, provide an INSTEAD OF UPDATE trigger or an unconditional ON UPDATE DO INSTEAD rule.")));
3090 : break;
3091 21 : case CMD_DELETE:
3092 21 : ereport(ERROR,
3774 tgl 3093 ECB : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
3094 : errmsg("cannot delete from view \"%s\"",
3095 : RelationGetRelationName(view)),
3096 : errdetail_internal("%s", _(auto_update_detail)),
3097 : errhint("To enable deleting from the view, provide an INSTEAD OF DELETE trigger or an unconditional ON DELETE DO INSTEAD rule.")));
3098 : break;
3774 tgl 3099 UIC 0 : default:
3774 tgl 3100 LBC 0 : elog(ERROR, "unrecognized CmdType: %d",
3101 : (int) parsetree->commandType);
3774 tgl 3102 ECB : break;
3103 : }
3104 : }
3105 :
3106 : /*
3460 rhaas 3107 : * For INSERT/UPDATE the modified columns must all be updatable. Note that
3108 : * we get the modified columns from the query's targetlist, not from the
2893 andres 3109 : * result RTE's insertedCols and/or updatedCols set, since
3110 : * rewriteTargetListIU may have added additional targetlist entries for
3111 : * view defaults, and these must also be updatable.
3112 : */
3460 rhaas 3113 CBC 1192 : if (parsetree->commandType != CMD_DELETE)
3460 rhaas 3114 ECB : {
3460 rhaas 3115 CBC 1045 : Bitmapset *modified_cols = NULL;
3116 : char *non_updatable_col;
3117 :
3460 rhaas 3118 GIC 2611 : foreach(lc, parsetree->targetList)
3460 rhaas 3119 ECB : {
3460 rhaas 3120 GIC 1566 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
3121 :
3122 1566 : if (!tle->resjunk)
3460 rhaas 3123 CBC 1566 : modified_cols = bms_add_member(modified_cols,
2118 tgl 3124 GIC 1566 : tle->resno - FirstLowInvalidHeapAttributeNumber);
3125 : }
3126 :
2893 andres 3127 1045 : if (parsetree->onConflict)
3128 : {
2893 andres 3129 CBC 162 : foreach(lc, parsetree->onConflict->onConflictSet)
3130 : {
3131 78 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
2893 andres 3132 ECB :
2893 andres 3133 GIC 78 : if (!tle->resjunk)
3134 78 : modified_cols = bms_add_member(modified_cols,
2118 tgl 3135 78 : tle->resno - FirstLowInvalidHeapAttributeNumber);
3136 : }
3137 : }
3138 :
3460 rhaas 3139 CBC 1045 : auto_update_detail = view_cols_are_auto_updatable(viewquery,
3460 rhaas 3140 ECB : modified_cols,
3141 : NULL,
3142 : &non_updatable_col);
3460 rhaas 3143 GIC 1045 : if (auto_update_detail)
3144 : {
3145 : /*
3146 : * This is a different error, caused by an attempt to update a
3460 rhaas 3147 EUB : * non-updatable column in an otherwise updatable view.
3148 : */
3460 rhaas 3149 GIC 54 : switch (parsetree->commandType)
3150 : {
3151 33 : case CMD_INSERT:
3152 33 : ereport(ERROR,
3153 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3154 : errmsg("cannot insert into column \"%s\" of view \"%s\"",
3155 : non_updatable_col,
2118 tgl 3156 ECB : RelationGetRelationName(view)),
3157 : errdetail_internal("%s", _(auto_update_detail))));
3158 : break;
3460 rhaas 3159 GIC 21 : case CMD_UPDATE:
3160 21 : ereport(ERROR,
3161 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2118 tgl 3162 ECB : errmsg("cannot update column \"%s\" of view \"%s\"",
3163 : non_updatable_col,
3164 : RelationGetRelationName(view)),
3165 : errdetail_internal("%s", _(auto_update_detail))));
3460 rhaas 3166 : break;
3460 rhaas 3167 LBC 0 : default:
3168 0 : elog(ERROR, "unrecognized CmdType: %d",
3169 : (int) parsetree->commandType);
3170 : break;
3171 : }
3172 : }
3173 : }
3174 :
3175 : /* Locate RTE describing the view in the outer query */
3774 tgl 3176 GIC 1138 : view_rte = rt_fetch(parsetree->resultRelation, parsetree->rtable);
3774 tgl 3177 ECB :
3178 : /*
3179 : * If we get here, view_query_is_auto_updatable() has verified that the
3180 : * view contains a single base relation.
3181 : */
3774 tgl 3182 GIC 1138 : Assert(list_length(viewquery->jointree->fromlist) == 1);
2190 tgl 3183 CBC 1138 : rtr = linitial_node(RangeTblRef, viewquery->jointree->fromlist);
3184 :
3774 tgl 3185 GIC 1138 : base_rt_index = rtr->rtindex;
3186 1138 : base_rte = rt_fetch(base_rt_index, viewquery->rtable);
3187 1138 : Assert(base_rte->rtekind == RTE_RELATION);
124 alvherre 3188 GNC 1138 : base_perminfo = getRTEPermissionInfo(viewquery->rteperminfos, base_rte);
3189 :
3190 : /*
3191 : * Up to now, the base relation hasn't been touched at all in our query.
3774 tgl 3192 ECB : * We need to acquire lock on it before we try to do anything with it.
3193 : * (The subsequent recursive call of RewriteQuery will suppose that we
3194 : * already have the right lock!) Since it will become the query target
3195 : * relation, RowExclusiveLock is always the right thing.
3196 : */
1539 andres 3197 CBC 1138 : base_rel = table_open(base_rte->relid, RowExclusiveLock);
3198 :
3199 : /*
3200 : * While we have the relation open, update the RTE's relkind, just in case
3201 : * it changed since this view was made (cf. AcquireRewriteLocks).
3202 : */
3774 tgl 3203 GIC 1138 : base_rte->relkind = base_rel->rd_rel->relkind;
3204 :
3205 : /*
3206 : * If the view query contains any sublink subqueries then we need to also
3207 : * acquire locks on any relations they refer to. We know that there won't
3208 : * be any subqueries in the range table or CTEs, so we can skip those, as
3209 : * in AcquireRewriteLocks.
3210 : */
2770 sfrost 3211 1138 : if (viewquery->hasSubLinks)
2770 sfrost 3212 ECB : {
3213 : acquireLocksOnSubLinks_context context;
3214 :
2770 sfrost 3215 CBC 84 : context.for_execute = true;
3216 84 : query_tree_walker(viewquery, acquireLocksOnSubLinks, &context,
3217 : QTW_IGNORE_RC_SUBQUERIES);
3218 : }
3219 :
3220 : /*
3221 : * Create a new target RTE describing the base relation, and add it to the
3774 tgl 3222 ECB : * outer query's rangetable. (What's happening in the next few steps is
3223 : * very much like what the planner would do to "pull up" the view into the
3224 : * outer query. Perhaps someday we should refactor things enough so that
3225 : * we can share code with the planner.)
3226 : *
3227 : * Be sure to set rellockmode to the correct thing for the target table.
3228 : * Since we copied the whole viewquery above, we can just scribble on
3229 : * base_rte instead of copying it.
3230 : */
1652 tgl 3231 GIC 1138 : new_rte = base_rte;
3232 1138 : new_rte->rellockmode = RowExclusiveLock;
1652 tgl 3233 ECB :
3774 tgl 3234 GIC 1138 : parsetree->rtable = lappend(parsetree->rtable, new_rte);
3774 tgl 3235 CBC 1138 : new_rt_index = list_length(parsetree->rtable);
3236 :
3237 : /*
3238 : * INSERTs never inherit. For UPDATE/DELETE, we use the view query's
3239 : * inheritance flag for the base relation.
3240 : */
3567 tgl 3241 GIC 1138 : if (parsetree->commandType == CMD_INSERT)
3242 522 : new_rte->inh = false;
3243 :
3244 : /*
3245 : * Adjust the view's targetlist Vars to reference the new target RTE, ie
3246 : * make their varnos be new_rt_index instead of base_rt_index. There can
3247 : * be no Vars for other rels in the tlist, so this is sufficient to pull
3248 : * up the tlist expressions for use in the outer query. The tlist will
3249 : * provide the replacement expressions used by ReplaceVarsFromTargetList
3250 : * below.
3251 : */
2666 sfrost 3252 1138 : view_targetlist = viewquery->targetList;
3253 :
3774 tgl 3254 CBC 1138 : ChangeVarNodes((Node *) view_targetlist,
3255 : base_rt_index,
3256 : new_rt_index,
3257 : 0);
3258 :
3259 : /*
3260 : * If the view has "security_invoker" set, mark the new target relation
3261 : * for the permissions checks that we want to enforce against the query
3262 : * caller. Otherwise we want to enforce them against the view owner.
383 dean.a.rasheed 3263 ECB : *
3264 : * At the relation level, require the same INSERT/UPDATE/DELETE
3265 : * permissions that the query caller needs against the view. We drop the
3266 : * ACL_SELECT bit that is presumably in new_perminfo->requiredPerms
3267 : * initially.
3774 tgl 3268 : *
3269 : * Note: the original view's RTEPermissionInfo remains in the query's
3270 : * rteperminfos so that the executor still performs appropriate
3271 : * permissions checks for the query caller's use of the view.
3272 : */
124 alvherre 3273 GNC 1138 : view_perminfo = getRTEPermissionInfo(parsetree->rteperminfos, view_rte);
3274 :
3275 : /*
3276 : * Disregard the perminfo in viewquery->rteperminfos that the base_rte
3277 : * would currently be pointing at, because we'd like it to point now to a
3278 : * new one that will be filled below. Must set perminfoindex to 0 to not
3279 : * trip over the Assert in addRTEPermissionInfo().
3280 : */
3281 1138 : new_rte->perminfoindex = 0;
3282 1138 : new_perminfo = addRTEPermissionInfo(&parsetree->rteperminfos, new_rte);
383 dean.a.rasheed 3283 1138 : if (RelationHasSecurityInvoker(view))
124 alvherre 3284 129 : new_perminfo->checkAsUser = InvalidOid;
3285 : else
3286 1009 : new_perminfo->checkAsUser = view->rd_rel->relowner;
3287 1138 : new_perminfo->requiredPerms = view_perminfo->requiredPerms;
3288 :
3289 : /*
3290 : * Now for the per-column permissions bits.
3291 : *
3292 : * Initially, new_perminfo (base_perminfo) contains selectedCols
3293 : * permission check bits for all base-rel columns referenced by the view,
3294 : * but since the view is a SELECT query its insertedCols/updatedCols is
3295 : * empty. We set insertedCols and updatedCols to include all the columns
3296 : * the outer query is trying to modify, adjusting the column numbers as
3297 : * needed. But we leave selectedCols as-is, so the view owner must have
3298 : * read permission for all columns used in the view definition, even if
3299 : * some of them are not read by the outer query. We could try to limit
3300 : * selectedCols to only columns used in the transformed query, but that
3301 : * does not correspond to what happens in ordinary SELECT usage of a view:
3302 : * all referenced columns must have read permission, even if optimization
3303 : * finds that some of them can be discarded during query transformation.
3304 : * The flattening we're doing here is an optional optimization, too. (If
3305 : * you are unpersuaded and want to change this, note that applying
3306 : * adjust_view_column_set to view_perminfo->selectedCols is clearly *not*
3307 : * the right answer, since that neglects base-rel columns used in the
3308 : * view's WHERE quals.)
3774 tgl 3309 ECB : *
3310 : * This step needs the modified view targetlist, so we have to do things
3311 : * in this order.
3312 : */
124 alvherre 3313 GNC 1138 : Assert(bms_is_empty(new_perminfo->insertedCols) &&
3314 : bms_is_empty(new_perminfo->updatedCols));
3315 :
3316 1138 : new_perminfo->selectedCols = base_perminfo->selectedCols;
3317 :
3318 1138 : new_perminfo->insertedCols =
3319 1138 : adjust_view_column_set(view_perminfo->insertedCols, view_targetlist);
3320 :
3321 1138 : new_perminfo->updatedCols =
3322 1138 : adjust_view_column_set(view_perminfo->updatedCols, view_targetlist);
2893 andres 3323 ECB :
3324 : /*
3325 : * Move any security barrier quals from the view RTE onto the new target
3326 : * RTE. Any such quals should now apply to the new target RTE and will
3327 : * not reference the original view RTE in the rewritten query.
3328 : */
3284 sfrost 3329 GIC 1138 : new_rte->securityQuals = view_rte->securityQuals;
3284 sfrost 3330 CBC 1138 : view_rte->securityQuals = NIL;
3331 :
3332 : /*
3333 : * Now update all Vars in the outer query that reference the view to
3334 : * reference the appropriate column of the base relation instead.
3335 : */
3336 : parsetree = (Query *)
3774 tgl 3337 GIC 1138 : ReplaceVarsFromTargetList((Node *) parsetree,
3338 : parsetree->resultRelation,
3339 : 0,
3340 : view_rte,
3341 : view_targetlist,
3342 : REPLACEVARS_REPORT_ERROR,
3343 : 0,
3344 : &parsetree->hasSubLinks);
3774 tgl 3345 ECB :
3346 : /*
3347 : * Update all other RTI references in the query that point to the view
3348 : * (for example, parsetree->resultRelation itself) to point to the new
3349 : * base relation instead. Vars will not be affected since none of them
3350 : * reference parsetree->resultRelation any longer.
3351 : */
3774 tgl 3352 GIC 1138 : ChangeVarNodes((Node *) parsetree,
3353 : parsetree->resultRelation,
3354 : new_rt_index,
3355 : 0);
3356 1138 : Assert(parsetree->resultRelation == new_rt_index);
3357 :
3358 : /*
3359 : * For INSERT/UPDATE we must also update resnos in the targetlist to refer
3774 tgl 3360 ECB : * to columns of the base relation, since those indicate the target
3361 : * columns to be affected.
3362 : *
3363 : * Note that this destroys the resno ordering of the targetlist, but that
3364 : * will be fixed when we recurse through rewriteQuery, which will invoke
3365 : * rewriteTargetListIU again on the updated targetlist.
3366 : */
3774 tgl 3367 CBC 1138 : if (parsetree->commandType != CMD_DELETE)
3774 tgl 3368 EUB : {
3774 tgl 3369 GIC 2446 : foreach(lc, parsetree->targetList)
3774 tgl 3370 ECB : {
3774 tgl 3371 CBC 1455 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
3774 tgl 3372 ECB : TargetEntry *view_tle;
3373 :
3774 tgl 3374 GBC 1455 : if (tle->resjunk)
3774 tgl 3375 UIC 0 : continue;
3376 :
3774 tgl 3377 GIC 1455 : view_tle = get_tle_by_resno(view_targetlist, tle->resno);
3378 1455 : if (view_tle != NULL && !view_tle->resjunk && IsA(view_tle->expr, Var))
3379 1455 : tle->resno = ((Var *) view_tle->expr)->varattno;
3380 : else
3774 tgl 3381 UIC 0 : elog(ERROR, "attribute number %d not found in view targetlist",
3382 : tle->resno);
3774 tgl 3383 ECB : }
3384 : }
3385 :
3386 : /*
3387 : * For INSERT .. ON CONFLICT .. DO UPDATE, we must also update assorted
3388 : * stuff in the onConflict data structure.
3389 : */
1709 tgl 3390 GIC 1138 : if (parsetree->onConflict &&
3391 78 : parsetree->onConflict->action == ONCONFLICT_UPDATE)
3392 : {
3393 : Index old_exclRelIndex,
3394 : new_exclRelIndex;
3395 : ParseNamespaceItem *new_exclNSItem;
3396 : RangeTblEntry *new_exclRte;
1709 tgl 3397 ECB : List *tmp_tlist;
3398 :
3399 : /*
3400 : * Like the INSERT/UPDATE code above, update the resnos in the
3401 : * auxiliary UPDATE targetlist to refer to columns of the base
3402 : * relation.
1709 tgl 3403 EUB : */
1709 tgl 3404 GIC 144 : foreach(lc, parsetree->onConflict->onConflictSet)
1709 tgl 3405 ECB : {
1709 tgl 3406 CBC 72 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
1709 tgl 3407 ECB : TargetEntry *view_tle;
3408 :
1709 tgl 3409 GBC 72 : if (tle->resjunk)
1709 tgl 3410 UIC 0 : continue;
3411 :
1709 tgl 3412 GIC 72 : view_tle = get_tle_by_resno(view_targetlist, tle->resno);
3413 72 : if (view_tle != NULL && !view_tle->resjunk && IsA(view_tle->expr, Var))
3414 72 : tle->resno = ((Var *) view_tle->expr)->varattno;
3415 : else
1709 tgl 3416 UIC 0 : elog(ERROR, "attribute number %d not found in view targetlist",
3417 : tle->resno);
3418 : }
3419 :
3420 : /*
1709 tgl 3421 ECB : * Also, create a new RTE for the EXCLUDED pseudo-relation, using the
3422 : * query's new base rel (which may well have a different column list
3423 : * from the view, hence we need a new column alias list). This should
3424 : * match transformOnConflictClause. In particular, note that the
3425 : * relkind is set to composite to signal that we're not dealing with
3426 : * an actual relation.
3427 : */
1709 tgl 3428 CBC 72 : old_exclRelIndex = parsetree->onConflict->exclRelIndex;
1709 tgl 3429 ECB :
1193 tgl 3430 GIC 72 : new_exclNSItem = addRangeTableEntryForRelation(make_parsestate(NULL),
1193 tgl 3431 ECB : base_rel,
3432 : RowExclusiveLock,
3433 : makeAlias("excluded", NIL),
3434 : false, false);
1193 tgl 3435 CBC 72 : new_exclRte = new_exclNSItem->p_rte;
1709 tgl 3436 GIC 72 : new_exclRte->relkind = RELKIND_COMPOSITE_TYPE;
3437 : /* Ignore the RTEPermissionInfo that would've been added. */
124 alvherre 3438 GNC 72 : new_exclRte->perminfoindex = 0;
3439 :
1709 tgl 3440 GIC 72 : parsetree->rtable = lappend(parsetree->rtable, new_exclRte);
1709 tgl 3441 CBC 144 : new_exclRelIndex = parsetree->onConflict->exclRelIndex =
3442 72 : list_length(parsetree->rtable);
3443 :
3444 : /*
3445 : * Replace the targetlist for the EXCLUDED pseudo-relation with a new
3446 : * one, representing the columns from the new base relation.
3447 : */
1709 tgl 3448 GIC 144 : parsetree->onConflict->exclRelTlist =
3449 72 : BuildOnConflictExcludedTargetlist(base_rel, new_exclRelIndex);
3450 :
3451 : /*
1709 tgl 3452 ECB : * Update all Vars in the ON CONFLICT clause that refer to the old
3453 : * EXCLUDED pseudo-relation. We want to use the column mappings
3454 : * defined in the view targetlist, but we need the outputs to refer to
3455 : * the new EXCLUDED pseudo-relation rather than the new target RTE.
3456 : * Also notice that "EXCLUDED.*" will be expanded using the view's
3457 : * rowtype, which seems correct.
3458 : */
1709 tgl 3459 GIC 72 : tmp_tlist = copyObject(view_targetlist);
3460 :
3461 72 : ChangeVarNodes((Node *) tmp_tlist, new_rt_index,
3462 : new_exclRelIndex, 0);
3463 :
3464 72 : parsetree->onConflict = (OnConflictExpr *)
3465 72 : ReplaceVarsFromTargetList((Node *) parsetree->onConflict,
3466 : old_exclRelIndex,
3467 : 0,
3468 : view_rte,
3469 : tmp_tlist,
3470 : REPLACEVARS_REPORT_ERROR,
3471 : 0,
3472 : &parsetree->hasSubLinks);
3473 : }
3474 :
3475 : /*
3476 : * For UPDATE/DELETE, pull up any WHERE quals from the view. We know that
3477 : * any Vars in the quals must reference the one base relation, so we need
3478 : * only adjust their varnos to reference the new target (just the same as
3479 : * we did with the view targetlist).
3774 tgl 3480 ECB : *
2341 3481 : * If it's a security-barrier view, its WHERE quals must be applied before
3482 : * quals from the outer query, so we attach them to the RTE as security
3483 : * barrier quals rather than adding them to the main WHERE clause.
3484 : *
3485 : * For INSERT, the view's quals can be ignored in the main query.
3486 : */
3774 tgl 3487 GIC 1138 : if (parsetree->commandType != CMD_INSERT &&
3488 616 : viewquery->jointree->quals != NULL)
3489 : {
2666 sfrost 3490 CBC 247 : Node *viewqual = (Node *) viewquery->jointree->quals;
3491 :
2658 tgl 3492 ECB : /*
3493 : * Even though we copied viewquery already at the top of this
3494 : * function, we must duplicate the viewqual again here, because we may
3495 : * need to use the quals again below for a WithCheckOption clause.
3496 : */
2658 tgl 3497 GIC 247 : viewqual = copyObject(viewqual);
3498 :
3774 3499 247 : ChangeVarNodes(viewqual, base_rt_index, new_rt_index, 0);
3500 :
3284 sfrost 3501 247 : if (RelationIsSecurityView(view))
3502 : {
3503 : /*
2341 tgl 3504 ECB : * The view's quals go in front of existing barrier quals: those
3505 : * would have come from an outer level of security-barrier view,
3506 : * and so must get evaluated later.
3507 : *
3508 : * Note: the parsetree has been mutated, so the new_rte pointer is
3509 : * stale and needs to be re-computed.
3510 : */
3284 sfrost 3511 GIC 96 : new_rte = rt_fetch(new_rt_index, parsetree->rtable);
3512 96 : new_rte->securityQuals = lcons(viewqual, new_rte->securityQuals);
3513 :
3514 : /*
3515 : * Do not set parsetree->hasRowSecurity, because these aren't RLS
2341 tgl 3516 ECB : * conditions (they aren't affected by enabling/disabling RLS).
3517 : */
3518 :
3519 : /*
3284 sfrost 3520 : * Make sure that the query is marked correctly if the added qual
3521 : * has sublinks.
3522 : */
3284 sfrost 3523 GIC 96 : if (!parsetree->hasSubLinks)
3524 84 : parsetree->hasSubLinks = checkExprHasSubLink(viewqual);
3525 : }
3526 : else
3527 151 : AddQual(parsetree, (Node *) viewqual);
3774 tgl 3528 ECB : }
3529 :
3552 sfrost 3530 : /*
3531 : * For INSERT/UPDATE, if the view has the WITH CHECK OPTION, or any parent
3532 : * view specified WITH CASCADED CHECK OPTION, add the quals from the view
3533 : * to the query's withCheckOptions list.
3534 : */
3552 sfrost 3535 GIC 1138 : if (parsetree->commandType != CMD_DELETE)
3536 : {
3537 991 : bool has_wco = RelationHasCheckOption(view);
3538 991 : bool cascaded = RelationHasCascadedCheckOption(view);
3539 :
3540 : /*
3552 sfrost 3541 ECB : * If the parent view has a cascaded check option, treat this view as
3542 : * if it also had a cascaded check option.
3543 : *
3260 bruce 3544 : * New WithCheckOptions are added to the start of the list, so if
3545 : * there is a cascaded check option, it will be the first item in the
3546 : * list.
3547 : */
3552 sfrost 3548 CBC 991 : if (parsetree->withCheckOptions != NIL)
3552 sfrost 3549 ECB : {
3552 sfrost 3550 GIC 57 : WithCheckOption *parent_wco =
3260 bruce 3551 57 : (WithCheckOption *) linitial(parsetree->withCheckOptions);
3552 :
3552 sfrost 3553 57 : if (parent_wco->cascaded)
3554 : {
3555 45 : has_wco = true;
3556 45 : cascaded = true;
3557 : }
3558 : }
3559 :
3560 : /*
3561 : * Add the new WithCheckOption to the start of the list, so that
3552 sfrost 3562 ECB : * checks on inner views are run before checks on outer views, as
3563 : * required by the SQL standard.
3564 : *
3565 : * If the new check is CASCADED, we need to add it even if this view
3566 : * has no quals, since there may be quals on child views. A LOCAL
3567 : * check can be omitted if this view has no quals.
3568 : */
3552 sfrost 3569 CBC 991 : if (has_wco && (cascaded || viewquery->jointree->quals != NULL))
3552 sfrost 3570 ECB : {
3571 : WithCheckOption *wco;
3572 :
3552 sfrost 3573 CBC 289 : wco = makeNode(WithCheckOption);
2907 sfrost 3574 GIC 289 : wco->kind = WCO_VIEW_CHECK;
3575 289 : wco->relname = pstrdup(RelationGetRelationName(view));
2763 sfrost 3576 CBC 289 : wco->polname = NULL;
3552 sfrost 3577 GIC 289 : wco->qual = NULL;
3552 sfrost 3578 CBC 289 : wco->cascaded = cascaded;
3552 sfrost 3579 ECB :
3552 sfrost 3580 GIC 289 : parsetree->withCheckOptions = lcons(wco,
3581 : parsetree->withCheckOptions);
3582 :
3583 289 : if (viewquery->jointree->quals != NULL)
3584 : {
2666 3585 259 : wco->qual = (Node *) viewquery->jointree->quals;
3552 3586 259 : ChangeVarNodes(wco->qual, base_rt_index, new_rt_index, 0);
3587 :
3552 sfrost 3588 ECB : /*
3589 : * Make sure that the query is marked correctly if the added
3590 : * qual has sublinks. We can skip this check if the query is
3591 : * already marked, or if the command is an UPDATE, in which
3592 : * case the same qual will have already been added, and this
3593 : * check will already have been done.
3594 : */
3552 sfrost 3595 CBC 259 : if (!parsetree->hasSubLinks &&
3552 sfrost 3596 GIC 211 : parsetree->commandType != CMD_UPDATE)
3552 sfrost 3597 CBC 156 : parsetree->hasSubLinks = checkExprHasSubLink(wco->qual);
3598 : }
3599 : }
3600 : }
3601 :
1539 andres 3602 GIC 1138 : table_close(base_rel, NoLock);
3603 :
3774 tgl 3604 1138 : return parsetree;
3605 : }
3606 :
3607 :
3608 : /*
3609 : * RewriteQuery -
3610 : * rewrites the query and apply the rules again on the queries rewritten
3611 : *
3612 : * rewrite_events is a list of open query-rewrite actions, so we can detect
7348 tgl 3613 ECB : * infinite recursion.
3614 : *
127 dean.a.rasheed 3615 : * orig_rt_length is the length of the originating query's rtable, for product
3616 : * queries created by fireRules(), and 0 otherwise. This is used to skip any
3617 : * already-processed VALUES RTEs from the original query.
7477 tgl 3618 : */
9344 bruce 3619 : static List *
127 dean.a.rasheed 3620 CBC 213207 : RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
3621 : {
7348 tgl 3622 GIC 213207 : CmdType event = parsetree->commandType;
3623 213207 : bool instead = false;
6063 3624 213207 : bool returning = false;
2893 andres 3625 213207 : bool updatableview = false;
7348 tgl 3626 213207 : Query *qual_product = NULL;
3627 213207 : List *rewritten = NIL;
4426 tgl 3628 ECB : ListCell *lc1;
3629 :
4324 3630 : /*
3631 : * First, recursively process any insert/update/delete statements in WITH
3632 : * clauses. (We have to do this first because the WITH clauses may get
3633 : * copied into rule actions below.)
3634 : */
4324 tgl 3635 CBC 214716 : foreach(lc1, parsetree->cteList)
3636 : {
2190 3637 1524 : CommonTableExpr *cte = lfirst_node(CommonTableExpr, lc1);
2238 peter_e 3638 GIC 1524 : Query *ctequery = castNode(Query, cte->ctequery);
3639 : List *newstuff;
3640 :
4324 tgl 3641 1524 : if (ctequery->commandType == CMD_SELECT)
3642 1374 : continue;
3643 :
127 dean.a.rasheed 3644 CBC 150 : newstuff = RewriteQuery(ctequery, rewrite_events, 0);
3645 :
3646 : /*
4324 tgl 3647 ECB : * Currently we can only handle unconditional, single-statement DO
639 3648 : * INSTEAD rules correctly; we have to get exactly one non-utility
3649 : * Query out of the rewrite operation to stuff back into the CTE node.
4324 3650 : */
4324 tgl 3651 CBC 150 : if (list_length(newstuff) == 1)
3652 : {
3653 : /* Must check it's not a utility command */
2190 tgl 3654 GIC 138 : ctequery = linitial_node(Query, newstuff);
639 3655 138 : if (!(ctequery->commandType == CMD_SELECT ||
3656 138 : ctequery->commandType == CMD_UPDATE ||
639 tgl 3657 CBC 105 : ctequery->commandType == CMD_INSERT ||
639 tgl 3658 GIC 30 : ctequery->commandType == CMD_DELETE))
3659 : {
3660 : /*
3661 : * Currently it could only be NOTIFY; this error message will
639 tgl 3662 ECB : * need work if we ever allow other utility commands in rules.
3663 : */
639 tgl 3664 CBC 3 : ereport(ERROR,
3665 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
639 tgl 3666 ECB : errmsg("DO INSTEAD NOTIFY rules are not supported for data-modifying statements in WITH")));
3667 : }
4324 3668 : /* WITH queries should never be canSetTag */
4324 tgl 3669 GIC 135 : Assert(!ctequery->canSetTag);
3670 : /* Push the single Query back into the CTE node */
3671 135 : cte->ctequery = (Node *) ctequery;
3672 : }
3673 12 : else if (newstuff == NIL)
3674 : {
3675 3 : ereport(ERROR,
3676 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4324 tgl 3677 ECB : errmsg("DO INSTEAD NOTHING rules are not supported for data-modifying statements in WITH")));
3678 : }
3679 : else
3680 : {
3681 : ListCell *lc2;
3682 :
3683 : /* examine queries to determine which error message to issue */
4324 tgl 3684 GIC 21 : foreach(lc2, newstuff)
4324 tgl 3685 ECB : {
4324 tgl 3686 CBC 18 : Query *q = (Query *) lfirst(lc2);
3687 :
4324 tgl 3688 GIC 18 : if (q->querySource == QSRC_QUAL_INSTEAD_RULE)
3689 3 : ereport(ERROR,
3690 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4324 tgl 3691 ECB : errmsg("conditional DO INSTEAD rules are not supported for data-modifying statements in WITH")));
4324 tgl 3692 GIC 15 : if (q->querySource == QSRC_NON_INSTEAD_RULE)
3693 3 : ereport(ERROR,
3694 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3695 : errmsg("DO ALSO rules are not supported for data-modifying statements in WITH")));
3696 : }
3697 :
3698 3 : ereport(ERROR,
3699 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3700 : errmsg("multi-statement DO INSTEAD rules are not supported for data-modifying statements in WITH")));
3701 : }
3702 : }
3703 :
3704 : /*
377 alvherre 3705 ECB : * If the statement is an insert, update, delete, or merge, adjust its
3706 : * targetlist as needed, and then fire INSERT/UPDATE/DELETE rules on it.
3707 : *
3708 : * SELECT rules are handled later when we have all the queries that should
3709 : * get executed. Also, utilities aren't rewritten at all (do we still
3710 : * need that check?)
3711 : */
7348 tgl 3712 GIC 213192 : if (event != CMD_SELECT && event != CMD_UTILITY)
7348 tgl 3713 ECB : {
3714 : int result_relation;
3715 : RangeTblEntry *rt_entry;
3716 : Relation rt_entry_relation;
3717 : List *locks;
127 dean.a.rasheed 3718 : int product_orig_rt_length;
3774 tgl 3719 : List *product_queries;
2893 andres 3720 CBC 53580 : bool hasUpdate = false;
1509 dean.a.rasheed 3721 GIC 53580 : int values_rte_index = 0;
3722 53580 : bool defaults_remaining = false;
3723 :
7348 tgl 3724 53580 : result_relation = parsetree->resultRelation;
3725 53580 : Assert(result_relation != 0);
7348 tgl 3726 CBC 53580 : rt_entry = rt_fetch(result_relation, parsetree->rtable);
7348 tgl 3727 GIC 53580 : Assert(rt_entry->rtekind == RTE_RELATION);
3728 :
3729 : /*
3730 : * We can use NoLock here since either the parser or
6519 tgl 3731 ECB : * AcquireRewriteLocks should have locked the rel already.
3732 : */
1539 andres 3733 GIC 53580 : rt_entry_relation = table_open(rt_entry->relid, NoLock);
9345 bruce 3734 ECB :
3735 : /*
3736 : * Rewrite the targetlist as needed for the command type.
3737 : */
4564 tgl 3738 GIC 53580 : if (event == CMD_INSERT)
3739 : {
3740 : ListCell *lc2;
6094 mail 3741 42978 : RangeTblEntry *values_rte = NULL;
6094 mail 3742 ECB :
3743 : /*
127 dean.a.rasheed 3744 : * Test if it's a multi-row INSERT ... VALUES (...), (...), ... by
3745 : * looking for a VALUES RTE in the fromlist. For product queries,
3746 : * we must ignore any already-processed VALUES RTEs from the
3747 : * original query. These appear at the start of the rangetable.
6094 mail 3748 : */
127 dean.a.rasheed 3749 GIC 50990 : foreach(lc2, parsetree->jointree->fromlist)
3750 : {
127 dean.a.rasheed 3751 CBC 8012 : RangeTblRef *rtr = (RangeTblRef *) lfirst(lc2);
3752 :
127 dean.a.rasheed 3753 GIC 8012 : if (IsA(rtr, RangeTblRef) && rtr->rtindex > orig_rt_length)
6094 mail 3754 ECB : {
6094 mail 3755 GBC 7850 : RangeTblEntry *rte = rt_fetch(rtr->rtindex,
3756 : parsetree->rtable);
6094 mail 3757 ECB :
6094 mail 3758 CBC 7850 : if (rte->rtekind == RTE_VALUES)
3759 : {
3760 : /* should not find more than one VALUES RTE */
127 dean.a.rasheed 3761 GIC 2054 : if (values_rte != NULL)
127 dean.a.rasheed 3762 UIC 0 : elog(ERROR, "more than one VALUES RTE found");
127 dean.a.rasheed 3763 ECB :
6094 mail 3764 GIC 2054 : values_rte = rte;
1509 dean.a.rasheed 3765 CBC 2054 : values_rte_index = rtr->rtindex;
3766 : }
3767 : }
6094 mail 3768 ECB : }
3769 :
6094 mail 3770 GIC 42978 : if (values_rte)
3771 : {
868 tgl 3772 2054 : Bitmapset *unused_values_attrnos = NULL;
3773 :
3774 : /* Process the main targetlist ... */
2893 andres 3775 2054 : parsetree->targetList = rewriteTargetListIU(parsetree->targetList,
2118 tgl 3776 ECB : parsetree->commandType,
3777 : parsetree->override,
3778 : rt_entry_relation,
868 3779 : values_rte,
3780 : values_rte_index,
3781 : &unused_values_attrnos);
3782 : /* ... and the VALUES expression lists */
1498 dean.a.rasheed 3783 GIC 2024 : if (!rewriteValuesRTE(parsetree, values_rte, values_rte_index,
180 tgl 3784 ECB : rt_entry_relation,
868 3785 : unused_values_attrnos))
1509 dean.a.rasheed 3786 GIC 30 : defaults_remaining = true;
3787 : }
3788 : else
3789 : {
3790 : /* Process just the main targetlist */
2893 andres 3791 40897 : parsetree->targetList =
2893 andres 3792 CBC 40924 : rewriteTargetListIU(parsetree->targetList,
2893 andres 3793 ECB : parsetree->commandType,
3794 : parsetree->override,
3795 : rt_entry_relation,
868 tgl 3796 : NULL, 0, NULL);
3797 : }
3798 :
2893 andres 3799 GIC 42921 : if (parsetree->onConflict &&
3800 805 : parsetree->onConflict->action == ONCONFLICT_UPDATE)
3801 : {
3802 638 : parsetree->onConflict->onConflictSet =
2893 andres 3803 CBC 638 : rewriteTargetListIU(parsetree->onConflict->onConflictSet,
3804 : CMD_UPDATE,
2194 peter_e 3805 ECB : parsetree->override,
2893 andres 3806 : rt_entry_relation,
868 tgl 3807 : NULL, 0, NULL);
3808 : }
3809 : }
4564 tgl 3810 GIC 10602 : else if (event == CMD_UPDATE)
3811 : {
377 alvherre 3812 7959 : Assert(parsetree->override == OVERRIDING_NOT_SET);
2893 andres 3813 CBC 7947 : parsetree->targetList =
2893 andres 3814 GIC 7959 : rewriteTargetListIU(parsetree->targetList,
2194 peter_e 3815 ECB : parsetree->commandType,
3816 : parsetree->override,
3817 : rt_entry_relation,
3818 : NULL, 0, NULL);
3819 : }
377 alvherre 3820 CBC 2643 : else if (event == CMD_MERGE)
3821 : {
3822 468 : Assert(parsetree->override == OVERRIDING_NOT_SET);
3823 :
377 alvherre 3824 ECB : /*
3825 : * Rewrite each action targetlist separately
3826 : */
377 alvherre 3827 GIC 1179 : foreach(lc1, parsetree->mergeActionList)
377 alvherre 3828 ECB : {
377 alvherre 3829 CBC 714 : MergeAction *action = (MergeAction *) lfirst(lc1);
3830 :
377 alvherre 3831 GIC 714 : switch (action->commandType)
3832 : {
3833 112 : case CMD_NOTHING:
3834 : case CMD_DELETE: /* Nothing to do here */
3835 112 : break;
377 alvherre 3836 CBC 602 : case CMD_UPDATE:
377 alvherre 3837 ECB : case CMD_INSERT:
3838 :
3839 : /*
3840 : * MERGE actions do not permit multi-row INSERTs, so
3841 : * there is no VALUES RTE to deal with here.
127 dean.a.rasheed 3842 : */
377 alvherre 3843 GBC 599 : action->targetList =
3844 602 : rewriteTargetListIU(action->targetList,
3845 : action->commandType,
3846 : action->override,
3847 : rt_entry_relation,
3848 : NULL, 0, NULL);
377 alvherre 3849 CBC 599 : break;
377 alvherre 3850 UIC 0 : default:
3851 0 : elog(ERROR, "unrecognized commandType: %d", action->commandType);
3852 : break;
3853 : }
377 alvherre 3854 EUB : }
3855 : }
4564 tgl 3856 GIC 2175 : else if (event == CMD_DELETE)
3857 : {
3858 : /* Nothing to do here */
4564 tgl 3859 ECB : }
3860 : else
4564 tgl 3861 UIC 0 : elog(ERROR, "unrecognized commandType: %d", (int) event);
8318 tgl 3862 ECB :
7348 3863 : /*
3864 : * Collect and apply the appropriate rules.
3865 : */
7348 tgl 3866 GIC 53508 : locks = matchLocks(event, rt_entry_relation->rd_rules,
3867 : result_relation, parsetree, &hasUpdate);
3868 :
127 dean.a.rasheed 3869 53508 : product_orig_rt_length = list_length(parsetree->rtable);
1823 simon 3870 53508 : product_queries = fireRules(parsetree,
3871 : result_relation,
3872 : event,
3873 : locks,
3874 : &instead,
3875 : &returning,
3876 : &qual_product);
3877 :
3878 : /*
1509 dean.a.rasheed 3879 ECB : * If we have a VALUES RTE with any remaining untouched DEFAULT items,
3880 : * and we got any product queries, finalize the VALUES RTE for each
3881 : * product query (replacing the remaining DEFAULT items with NULLs).
3882 : * We don't do this for the original query, because we know that it
3883 : * must be an auto-insert on a view, and so should use the base
3884 : * relation's defaults for any remaining DEFAULT items.
3885 : */
1509 dean.a.rasheed 3886 GIC 53505 : if (defaults_remaining && product_queries != NIL)
3887 : {
3888 : ListCell *n;
3889 :
3890 : /*
3891 : * Each product query has its own copy of the VALUES RTE at the
1509 dean.a.rasheed 3892 ECB : * same index in the rangetable, so we must finalize each one.
3893 : *
45 3894 : * Note that if the product query is an INSERT ... SELECT, then
3895 : * the VALUES RTE will be at the same index in the SELECT part of
3896 : * the product query rather than the top-level product query
3897 : * itself.
1509 3898 : */
1509 dean.a.rasheed 3899 CBC 24 : foreach(n, product_queries)
3900 : {
3901 12 : Query *pt = (Query *) lfirst(n);
3902 : RangeTblEntry *values_rte;
45 dean.a.rasheed 3903 ECB :
45 dean.a.rasheed 3904 GIC 12 : if (pt->commandType == CMD_INSERT &&
45 dean.a.rasheed 3905 CBC 24 : pt->jointree && IsA(pt->jointree, FromExpr) &&
3906 12 : list_length(pt->jointree->fromlist) == 1)
3907 : {
3908 12 : Node *jtnode = (Node *) linitial(pt->jointree->fromlist);
45 dean.a.rasheed 3909 ECB :
45 dean.a.rasheed 3910 CBC 12 : if (IsA(jtnode, RangeTblRef))
45 dean.a.rasheed 3911 ECB : {
45 dean.a.rasheed 3912 CBC 12 : int rtindex = ((RangeTblRef *) jtnode)->rtindex;
45 dean.a.rasheed 3913 GIC 12 : RangeTblEntry *src_rte = rt_fetch(rtindex, pt->rtable);
3914 :
3915 12 : if (src_rte->rtekind == RTE_SUBQUERY &&
45 dean.a.rasheed 3916 CBC 3 : src_rte->subquery &&
3917 3 : IsA(src_rte->subquery, Query) &&
45 dean.a.rasheed 3918 GBC 3 : src_rte->subquery->commandType == CMD_SELECT)
45 dean.a.rasheed 3919 GIC 3 : pt = src_rte->subquery;
45 dean.a.rasheed 3920 ECB : }
3921 : }
3922 :
45 dean.a.rasheed 3923 GIC 12 : values_rte = rt_fetch(values_rte_index, pt->rtable);
3924 12 : if (values_rte->rtekind != RTE_VALUES)
45 dean.a.rasheed 3925 UIC 0 : elog(ERROR, "failed to find VALUES RTE in product query");
3926 :
180 tgl 3927 GIC 12 : rewriteValuesRTEToNulls(pt, values_rte);
3928 : }
3929 : }
3930 :
3931 : /*
3932 : * If there was no unqualified INSTEAD rule, and the target relation
3933 : * is a view without any INSTEAD OF triggers, see if the view can be
3934 : * automatically updated. If so, we perform the necessary query
3935 : * transformation here and add the resulting query to the
3936 : * product_queries list, so that it gets recursively rewritten if
3937 : * necessary.
1181 dean.a.rasheed 3938 ECB : *
3939 : * If the view cannot be automatically updated, we throw an error here
3940 : * which is OK since the query would fail at runtime anyway. Throwing
3941 : * the error here is preferable to the executor check since we have
3942 : * more detailed information available about why the view isn't
3943 : * updatable.
3944 : */
1181 dean.a.rasheed 3945 GIC 53505 : if (!instead &&
3774 tgl 3946 53184 : rt_entry_relation->rd_rel->relkind == RELKIND_VIEW &&
3947 1411 : !view_has_instead_trigger(rt_entry_relation, event))
3948 : {
3949 : /*
3950 : * If there were any qualified INSTEAD rules, don't allow the view
1181 dean.a.rasheed 3951 ECB : * to be automatically updated (an unqualified INSTEAD rule or
3952 : * INSTEAD OF trigger is required).
3953 : *
3954 : * The messages here should match execMain.c's CheckValidResultRel
3955 : * and in principle make those checks in executor unnecessary, but
3956 : * we keep them just in case.
3957 : */
1181 dean.a.rasheed 3958 GIC 1255 : if (qual_product != NULL)
3959 : {
3960 9 : switch (parsetree->commandType)
3961 : {
3962 3 : case CMD_INSERT:
1181 dean.a.rasheed 3963 CBC 3 : ereport(ERROR,
1181 dean.a.rasheed 3964 ECB : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
3965 : errmsg("cannot insert into view \"%s\"",
3966 : RelationGetRelationName(rt_entry_relation)),
3967 : errdetail("Views with conditional DO INSTEAD rules are not automatically updatable."),
3968 : errhint("To enable inserting into the view, provide an INSTEAD OF INSERT trigger or an unconditional ON INSERT DO INSTEAD rule.")));
3969 : break;
1181 dean.a.rasheed 3970 GIC 3 : case CMD_UPDATE:
1181 dean.a.rasheed 3971 CBC 3 : ereport(ERROR,
1181 dean.a.rasheed 3972 ECB : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
3973 : errmsg("cannot update view \"%s\"",
3974 : RelationGetRelationName(rt_entry_relation)),
3975 : errdetail("Views with conditional DO INSTEAD rules are not automatically updatable."),
3976 : errhint("To enable updating the view, provide an INSTEAD OF UPDATE trigger or an unconditional ON UPDATE DO INSTEAD rule.")));
3977 : break;
1181 dean.a.rasheed 3978 GIC 3 : case CMD_DELETE:
1181 dean.a.rasheed 3979 GBC 3 : ereport(ERROR,
1181 dean.a.rasheed 3980 EUB : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
3981 : errmsg("cannot delete from view \"%s\"",
3982 : RelationGetRelationName(rt_entry_relation)),
3983 : errdetail("Views with conditional DO INSTEAD rules are not automatically updatable."),
3984 : errhint("To enable deleting from the view, provide an INSTEAD OF DELETE trigger or an unconditional ON DELETE DO INSTEAD rule.")));
3985 : break;
1181 dean.a.rasheed 3986 UIC 0 : default:
3987 0 : elog(ERROR, "unrecognized CmdType: %d",
3988 : (int) parsetree->commandType);
3989 : break;
3990 : }
1181 dean.a.rasheed 3991 ECB : }
3992 :
3993 : /*
3994 : * Attempt to rewrite the query to automatically update the view.
3995 : * This throws an error if the view can't be automatically
3996 : * updated.
3997 : */
3774 tgl 3998 GIC 1246 : parsetree = rewriteTargetView(parsetree, rt_entry_relation);
8955 bruce 3999 ECB :
3774 tgl 4000 : /*
4001 : * At this point product_queries contains any DO ALSO rule
3260 bruce 4002 : * actions. Add the rewritten query before or after those. This
4003 : * must match the handling the original query would have gotten
4004 : * below, if we allowed it to be included again.
4005 : */
3774 tgl 4006 GIC 1138 : if (parsetree->commandType == CMD_INSERT)
4007 522 : product_queries = lcons(parsetree, product_queries);
4008 : else
4009 616 : product_queries = lappend(product_queries, parsetree);
4010 :
3774 tgl 4011 ECB : /*
4012 : * Set the "instead" flag, as if there had been an unqualified
4013 : * INSTEAD, to prevent the original query from being included a
4014 : * second time below. The transformation will have rewritten any
4015 : * RETURNING list, so we can also set "returning" to forestall
4016 : * throwing an error below.
4017 : */
3774 tgl 4018 GIC 1138 : instead = true;
4019 1138 : returning = true;
2893 andres 4020 CBC 1138 : updatableview = true;
4021 : }
4022 :
4023 : /*
4024 : * If we got any product queries, recursively rewrite them --- but
3602 bruce 4025 ECB : * first check for recursion!
4026 : */
3602 bruce 4027 CBC 53388 : if (product_queries != NIL)
3602 bruce 4028 ECB : {
3602 bruce 4029 EUB : ListCell *n;
4030 : rewrite_event *rev;
4031 :
3602 bruce 4032 GIC 2032 : foreach(n, rewrite_events)
4033 : {
4034 357 : rev = (rewrite_event *) lfirst(n);
4035 357 : if (rev->relation == RelationGetRelid(rt_entry_relation) &&
3602 bruce 4036 LBC 0 : rev->event == event)
4037 0 : ereport(ERROR,
3602 bruce 4038 ECB : (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
4039 : errmsg("infinite recursion detected in rules for relation \"%s\"",
4040 : RelationGetRelationName(rt_entry_relation))));
4041 : }
4042 :
3602 bruce 4043 CBC 1675 : rev = (rewrite_event *) palloc(sizeof(rewrite_event));
3602 bruce 4044 GIC 1675 : rev->relation = RelationGetRelid(rt_entry_relation);
4045 1675 : rev->event = event;
1362 tgl 4046 1675 : rewrite_events = lappend(rewrite_events, rev);
4047 :
3602 bruce 4048 3422 : foreach(n, product_queries)
4049 : {
4050 1792 : Query *pt = (Query *) lfirst(n);
4051 : List *newstuff;
4052 :
4053 : /*
4054 : * For an updatable view, pt might be the rewritten version of
127 dean.a.rasheed 4055 ECB : * the original query, in which case we pass on orig_rt_length
4056 : * to finish processing any VALUES RTE it contained.
4057 : *
4058 : * Otherwise, we have a product query created by fireRules().
4059 : * Any VALUES RTEs from the original query have been fully
4060 : * processed, and must be skipped when we recurse.
4061 : */
127 dean.a.rasheed 4062 CBC 1792 : newstuff = RewriteQuery(pt, rewrite_events,
4063 : pt == parsetree ?
4064 : orig_rt_length :
4065 : product_orig_rt_length);
3602 bruce 4066 GIC 1747 : rewritten = list_concat(rewritten, newstuff);
4067 : }
4068 :
1362 tgl 4069 1630 : rewrite_events = list_delete_last(rewrite_events);
4070 : }
4071 :
6063 tgl 4072 ECB : /*
6031 bruce 4073 : * If there is an INSTEAD, and the original query has a RETURNING, we
4074 : * have to have found a RETURNING in the rule(s), else fail. (Because
4075 : * DefineQueryRewrite only allows RETURNING in unconditional INSTEAD
4076 : * rules, there's no need to worry whether the substituted RETURNING
4077 : * will actually be executed --- it must be.)
6063 tgl 4078 : */
6063 tgl 4079 CBC 53343 : if ((instead || qual_product != NULL) &&
6063 tgl 4080 GIC 1570 : parsetree->returningList &&
4081 105 : !returning)
4082 : {
4083 3 : switch (event)
4084 : {
6063 tgl 4085 GBC 3 : case CMD_INSERT:
4086 3 : ereport(ERROR,
4087 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4088 : errmsg("cannot perform INSERT RETURNING on relation \"%s\"",
4089 : RelationGetRelationName(rt_entry_relation)),
4090 : errhint("You need an unconditional ON INSERT DO INSTEAD rule with a RETURNING clause.")));
4091 : break;
6063 tgl 4092 UBC 0 : case CMD_UPDATE:
4093 0 : ereport(ERROR,
4094 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4095 : errmsg("cannot perform UPDATE RETURNING on relation \"%s\"",
4096 : RelationGetRelationName(rt_entry_relation)),
4097 : errhint("You need an unconditional ON UPDATE DO INSTEAD rule with a RETURNING clause.")));
4098 : break;
4099 0 : case CMD_DELETE:
4100 0 : ereport(ERROR,
4101 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4102 : errmsg("cannot perform DELETE RETURNING on relation \"%s\"",
4103 : RelationGetRelationName(rt_entry_relation)),
4104 : errhint("You need an unconditional ON DELETE DO INSTEAD rule with a RETURNING clause.")));
4105 : break;
6063 tgl 4106 UIC 0 : default:
4107 0 : elog(ERROR, "unrecognized commandType: %d",
4108 : (int) event);
4109 : break;
6063 tgl 4110 ECB : }
4111 : }
4112 :
2893 andres 4113 : /*
4114 : * Updatable views are supported by ON CONFLICT, so don't prevent that
4115 : * case from proceeding
4116 : */
2893 andres 4117 CBC 53340 : if (parsetree->onConflict &&
2893 andres 4118 GIC 715 : (product_queries != NIL || hasUpdate) &&
4119 84 : !updatableview)
2878 bruce 4120 6 : ereport(ERROR,
4121 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4122 : errmsg("INSERT with ON CONFLICT clause cannot be used with table that has INSERT or UPDATE rules")));
4123 :
1539 andres 4124 53334 : table_close(rt_entry_relation, NoLock);
4125 : }
4126 :
4127 : /*
4128 : * For INSERTs, the original query is done first; for UPDATE/DELETE, it is
4129 : * done last. This is needed because update and delete rule actions might
4130 : * not do anything if they are invoked after the update or delete is
4131 : * performed. The command counter increment between the query executions
6385 bruce 4132 ECB : * makes the deleted (and maybe the updated) tuples disappear so the scans
4133 : * for them in the rule actions cannot find them.
7477 tgl 4134 : *
4135 : * If we found any unqualified INSTEAD, the original query is not done at
7188 bruce 4136 : * all, in any form. Otherwise, we add the modified form if qualified
4137 : * INSTEADs were found, else the unmodified form.
4138 : */
7477 tgl 4139 CBC 212946 : if (!instead)
4140 : {
7477 tgl 4141 GIC 211541 : if (parsetree->commandType == CMD_INSERT)
4142 : {
7477 tgl 4143 CBC 42165 : if (qual_product != NULL)
4144 147 : rewritten = lcons(qual_product, rewritten);
4145 : else
4146 42018 : rewritten = lcons(parsetree, rewritten);
4147 : }
4148 : else
4149 : {
7477 tgl 4150 GIC 169376 : if (qual_product != NULL)
4151 9 : rewritten = lappend(rewritten, qual_product);
4152 : else
4153 169367 : rewritten = lappend(rewritten, parsetree);
4154 : }
4155 : }
4156 :
4157 : /*
4324 tgl 4158 ECB : * If the original query has a CTE list, and we generated more than one
4159 : * non-utility result query, we have to fail because we'll have copied the
4322 bruce 4160 : * CTE list into each result query. That would break the expectation of
4161 : * single evaluation of CTEs. This could possibly be fixed by
4324 tgl 4162 : * restructuring so that a CTE list can be shared across multiple Query
4163 : * and PlannableStatement nodes.
4164 : */
4324 tgl 4165 GIC 212946 : if (parsetree->cteList != NIL)
4324 tgl 4166 ECB : {
4322 bruce 4167 CBC 1153 : int qcount = 0;
4168 :
4324 tgl 4169 2306 : foreach(lc1, rewritten)
4324 tgl 4170 EUB : {
4324 tgl 4171 GIC 1153 : Query *q = (Query *) lfirst(lc1);
4172 :
4173 1153 : if (q->commandType != CMD_UTILITY)
4174 1153 : qcount++;
4324 tgl 4175 ECB : }
4324 tgl 4176 GIC 1153 : if (qcount > 1)
4324 tgl 4177 UIC 0 : ereport(ERROR,
4178 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4179 : errmsg("WITH cannot be used in a query that is rewritten by rules into multiple queries")));
4180 : }
4181 :
9345 bruce 4182 GIC 212946 : return rewritten;
4183 : }
4184 :
4185 :
4186 : /*
4187 : * QueryRewrite -
4188 : * Primary entry point to the query rewriter.
8221 tgl 4189 ECB : * Rewrite one query via query rewrite system, possibly returning 0
4190 : * or many queries.
4191 : *
4192 : * NOTE: the parsetree must either have come straight from the parser,
4193 : * or have been scanned by AcquireRewriteLocks to acquire suitable locks.
4194 : */
4195 : List *
8221 tgl 4196 GIC 211265 : QueryRewrite(Query *parsetree)
4197 : {
2006 rhaas 4198 211265 : uint64 input_query_id = parsetree->queryId;
4199 : List *querylist;
4200 : List *results;
4201 : ListCell *l;
7282 tgl 4202 ECB : CmdType origCmdType;
4203 : bool foundOriginalQuery;
4204 : Query *lastInstead;
4205 :
4206 : /*
4207 : * This function is only applied to top-level original queries
4208 : */
4426 tgl 4209 GIC 211265 : Assert(parsetree->querySource == QSRC_ORIGINAL);
4426 tgl 4210 CBC 211265 : Assert(parsetree->canSetTag);
4211 :
4212 : /*
4213 : * Step 1
4214 : *
4215 : * Apply all non-SELECT rules possibly getting 0 or many queries
4216 : */
127 dean.a.rasheed 4217 GIC 211265 : querylist = RewriteQuery(parsetree, NIL, 0);
4218 :
8955 bruce 4219 ECB : /*
8560 tgl 4220 : * Step 2
4221 : *
8955 bruce 4222 : * Apply all the RIR rules on each query
4223 : *
4030 tgl 4224 : * This is also a handy place to mark each query with the original queryId
4225 : */
4564 tgl 4226 CBC 211049 : results = NIL;
8720 bruce 4227 GIC 422377 : foreach(l, querylist)
8720 bruce 4228 ECB : {
8053 bruce 4229 GIC 211376 : Query *query = (Query *) lfirst(l);
4230 :
1821 tgl 4231 211376 : query = fireRIRrules(query, NIL);
4232 :
4030 4233 211328 : query->queryId = input_query_id;
4234 :
8221 4235 211328 : results = lappend(results, query);
4236 : }
4237 :
4238 : /*
4239 : * Step 3
4240 : *
4241 : * Determine which, if any, of the resulting queries is supposed to set
4242 : * the command-result tag; and update the canSetTag fields accordingly.
4243 : *
4244 : * If the original query is still in the list, it sets the command tag.
4245 : * Otherwise, the last INSTEAD query of the same kind as the original is
4246 : * allowed to set the tag. (Note these rules can leave us with no query
6385 bruce 4247 ECB : * setting the tag. The tcop code has to cope with this by setting up a
4248 : * default tag based on the original un-rewritten query.)
7282 tgl 4249 : *
4250 : * The Asserts verify that at most one query in the result list is marked
6385 bruce 4251 : * canSetTag. If we aren't checking asserts, we can fall out of the loop
4252 : * as soon as we find the original query.
7282 tgl 4253 : */
7282 tgl 4254 GIC 211001 : origCmdType = parsetree->commandType;
7282 tgl 4255 CBC 211001 : foundOriginalQuery = false;
7282 tgl 4256 GIC 211001 : lastInstead = NULL;
7282 tgl 4257 ECB :
7282 tgl 4258 CBC 422329 : foreach(l, results)
7282 tgl 4259 ECB : {
7282 tgl 4260 GIC 211328 : Query *query = (Query *) lfirst(l);
4261 :
4262 211328 : if (query->querySource == QSRC_ORIGINAL)
4263 : {
4264 210704 : Assert(query->canSetTag);
4265 210704 : Assert(!foundOriginalQuery);
7282 tgl 4266 CBC 210704 : foundOriginalQuery = true;
7282 tgl 4267 ECB : #ifndef USE_ASSERT_CHECKING
4268 : break;
4269 : #endif
4270 : }
4271 : else
4272 : {
7282 tgl 4273 GIC 624 : Assert(!query->canSetTag);
7282 tgl 4274 CBC 624 : if (query->commandType == origCmdType &&
4275 510 : (query->querySource == QSRC_INSTEAD_RULE ||
7282 tgl 4276 GIC 264 : query->querySource == QSRC_QUAL_INSTEAD_RULE))
7282 tgl 4277 CBC 360 : lastInstead = query;
4278 : }
4279 : }
4280 :
7282 tgl 4281 GIC 211001 : if (!foundOriginalQuery && lastInstead != NULL)
4282 258 : lastInstead->canSetTag = true;
4283 :
8221 4284 211001 : return results;
4285 : }
|
