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Rethink the way FSM truncation works. Instead of WAL-logging FSM
[PostgreSQL.git] / src / backend / rewrite / rewriteDefine.c
blobac7a29aa3a8eb2d1c85d9ba66204ba33a71a13b3
1 /*-------------------------------------------------------------------------
2 *
3 * rewriteDefine.c
4 * routines for defining a rewrite rule
5 *
6 * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * $PostgreSQL$
12 *
13 *-------------------------------------------------------------------------
14 */
15 #include "postgres.h"
16
17 #include "access/heapam.h"
18 #include "catalog/dependency.h"
19 #include "catalog/indexing.h"
20 #include "catalog/namespace.h"
21 #include "catalog/pg_rewrite.h"
22 #include "catalog/storage.h"
23 #include "miscadmin.h"
24 #include "nodes/nodeFuncs.h"
25 #include "parser/parse_utilcmd.h"
26 #include "rewrite/rewriteDefine.h"
27 #include "rewrite/rewriteManip.h"
28 #include "rewrite/rewriteSupport.h"
29 #include "utils/acl.h"
30 #include "utils/builtins.h"
31 #include "utils/inval.h"
32 #include "utils/lsyscache.h"
33 #include "utils/rel.h"
34 #include "utils/syscache.h"
35 #include "utils/tqual.h"
36
37
38 static void checkRuleResultList(List *targetList, TupleDesc resultDesc,
39 bool isSelect);
40 static bool setRuleCheckAsUser_walker(Node *node, Oid *context);
41 static void setRuleCheckAsUser_Query(Query *qry, Oid userid);
42
43
44 /*
45 * InsertRule -
46 * takes the arguments and inserts them as a row into the system
47 * relation "pg_rewrite"
48 */
49 static Oid
50 InsertRule(char *rulname,
51 int evtype,
52 Oid eventrel_oid,
53 AttrNumber evslot_index,
54 bool evinstead,
55 Node *event_qual,
56 List *action,
57 bool replace)
58 {
59 char *evqual = nodeToString(event_qual);
60 char *actiontree = nodeToString((Node *) action);
61 int i;
62 Datum values[Natts_pg_rewrite];
63 bool nulls[Natts_pg_rewrite];
64 bool replaces[Natts_pg_rewrite];
65 NameData rname;
66 Relation pg_rewrite_desc;
67 HeapTuple tup,
68 oldtup;
69 Oid rewriteObjectId;
70 ObjectAddress myself,
71 referenced;
72 bool is_update = false;
73
74 /*
75 * Set up *nulls and *values arrays
76 */
77 MemSet(nulls, false, sizeof(nulls));
78
79 i = 0;
80 namestrcpy(&rname, rulname);
81 values[i++] = NameGetDatum(&rname); /* rulename */
82 values[i++] = ObjectIdGetDatum(eventrel_oid); /* ev_class */
83 values[i++] = Int16GetDatum(evslot_index); /* ev_attr */
84 values[i++] = CharGetDatum(evtype + '0'); /* ev_type */
85 values[i++] = CharGetDatum(RULE_FIRES_ON_ORIGIN); /* ev_enabled */
86 values[i++] = BoolGetDatum(evinstead); /* is_instead */
87 values[i++] = CStringGetTextDatum(evqual); /* ev_qual */
88 values[i++] = CStringGetTextDatum(actiontree); /* ev_action */
89
90 /*
91 * Ready to store new pg_rewrite tuple
92 */
93 pg_rewrite_desc = heap_open(RewriteRelationId, RowExclusiveLock);
94
95 /*
96 * Check to see if we are replacing an existing tuple
97 */
98 oldtup = SearchSysCache(RULERELNAME,
99 ObjectIdGetDatum(eventrel_oid),
100 PointerGetDatum(rulname),
101 0, 0);
102
103 if (HeapTupleIsValid(oldtup))
104 {
105 if (!replace)
106 ereport(ERROR,
107 (errcode(ERRCODE_DUPLICATE_OBJECT),
108 errmsg("rule \"%s\" for relation \"%s\" already exists",
109 rulname, get_rel_name(eventrel_oid))));
110
111 /*
112 * When replacing, we don't need to replace every attribute
113 */
114 MemSet(replaces, false, sizeof(replaces));
115 replaces[Anum_pg_rewrite_ev_attr - 1] = true;
116 replaces[Anum_pg_rewrite_ev_type - 1] = true;
117 replaces[Anum_pg_rewrite_is_instead - 1] = true;
118 replaces[Anum_pg_rewrite_ev_qual - 1] = true;
119 replaces[Anum_pg_rewrite_ev_action - 1] = true;
120
121 tup = heap_modify_tuple(oldtup, RelationGetDescr(pg_rewrite_desc),
122 values, nulls, replaces);
123
124 simple_heap_update(pg_rewrite_desc, &tup->t_self, tup);
125
126 ReleaseSysCache(oldtup);
127
128 rewriteObjectId = HeapTupleGetOid(tup);
129 is_update = true;
130 }
131 else
132 {
133 tup = heap_form_tuple(pg_rewrite_desc->rd_att, values, nulls);
134
135 rewriteObjectId = simple_heap_insert(pg_rewrite_desc, tup);
136 }
137
138 /* Need to update indexes in either case */
139 CatalogUpdateIndexes(pg_rewrite_desc, tup);
140
141 heap_freetuple(tup);
142
143 /* If replacing, get rid of old dependencies and make new ones */
144 if (is_update)
145 deleteDependencyRecordsFor(RewriteRelationId, rewriteObjectId);
146
147 /*
148 * Install dependency on rule's relation to ensure it will go away on
149 * relation deletion. If the rule is ON SELECT, make the dependency
150 * implicit --- this prevents deleting a view's SELECT rule. Other kinds
151 * of rules can be AUTO.
152 */
153 myself.classId = RewriteRelationId;
154 myself.objectId = rewriteObjectId;
155 myself.objectSubId = 0;
156
157 referenced.classId = RelationRelationId;
158 referenced.objectId = eventrel_oid;
159 referenced.objectSubId = 0;
160
161 recordDependencyOn(&myself, &referenced,
162 (evtype == CMD_SELECT) ? DEPENDENCY_INTERNAL : DEPENDENCY_AUTO);
163
164 /*
165 * Also install dependencies on objects referenced in action and qual.
166 */
167 recordDependencyOnExpr(&myself, (Node *) action, NIL,
168 DEPENDENCY_NORMAL);
169
170 if (event_qual != NULL)
171 {
172 /* Find query containing OLD/NEW rtable entries */
173 Query *qry = (Query *) linitial(action);
174
175 qry = getInsertSelectQuery(qry, NULL);
176 recordDependencyOnExpr(&myself, event_qual, qry->rtable,
177 DEPENDENCY_NORMAL);
178 }
179
180 heap_close(pg_rewrite_desc, RowExclusiveLock);
181
182 return rewriteObjectId;
183 }
184
185 /*
186 * DefineRule
187 * Execute a CREATE RULE command.
188 */
189 void
190 DefineRule(RuleStmt *stmt, const char *queryString)
191 {
192 List *actions;
193 Node *whereClause;
194 Oid relId;
195
196 /* Parse analysis ... */
197 transformRuleStmt(stmt, queryString, &actions, &whereClause);
198
199 /* ... find the relation ... */
200 relId = RangeVarGetRelid(stmt->relation, false);
201
202 /* ... and execute */
203 DefineQueryRewrite(stmt->rulename,
204 relId,
205 whereClause,
206 stmt->event,
207 stmt->instead,
208 stmt->replace,
209 actions);
210 }
211
212
213 /*
214 * DefineQueryRewrite
215 * Create a rule
216 *
217 * This is essentially the same as DefineRule() except that the rule's
218 * action and qual have already been passed through parse analysis.
219 */
220 void
221 DefineQueryRewrite(char *rulename,
222 Oid event_relid,
223 Node *event_qual,
224 CmdType event_type,
225 bool is_instead,
226 bool replace,
227 List *action)
228 {
229 Relation event_relation;
230 Oid ruleId;
231 int event_attno;
232 ListCell *l;
233 Query *query;
234 bool RelisBecomingView = false;
235
236 /*
237 * If we are installing an ON SELECT rule, we had better grab
238 * AccessExclusiveLock to ensure no SELECTs are currently running on the
239 * event relation. For other types of rules, it might be sufficient to
240 * grab ShareLock to lock out insert/update/delete actions. But for now,
241 * let's just grab AccessExclusiveLock all the time.
242 */
243 event_relation = heap_open(event_relid, AccessExclusiveLock);
244
245 /*
246 * Check user has permission to apply rules to this relation.
247 */
248 if (!pg_class_ownercheck(event_relid, GetUserId()))
249 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
250 RelationGetRelationName(event_relation));
251
252 /*
253 * No rule actions that modify OLD or NEW
254 */
255 foreach(l, action)
256 {
257 query = (Query *) lfirst(l);
258 if (query->resultRelation == 0)
259 continue;
260 /* Don't be fooled by INSERT/SELECT */
261 if (query != getInsertSelectQuery(query, NULL))
262 continue;
263 if (query->resultRelation == PRS2_OLD_VARNO)
264 ereport(ERROR,
265 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
266 errmsg("rule actions on OLD are not implemented"),
267 errhint("Use views or triggers instead.")));
268 if (query->resultRelation == PRS2_NEW_VARNO)
269 ereport(ERROR,
270 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
271 errmsg("rule actions on NEW are not implemented"),
272 errhint("Use triggers instead.")));
273 }
274
275 if (event_type == CMD_SELECT)
276 {
277 /*
278 * Rules ON SELECT are restricted to view definitions
279 *
280 * So there cannot be INSTEAD NOTHING, ...
281 */
282 if (list_length(action) == 0)
283 ereport(ERROR,
284 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
285 errmsg("INSTEAD NOTHING rules on SELECT are not implemented"),
286 errhint("Use views instead.")));
287
288 /*
289 * ... there cannot be multiple actions, ...
290 */
291 if (list_length(action) > 1)
292 ereport(ERROR,
293 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
294 errmsg("multiple actions for rules on SELECT are not implemented")));
295
296 /*
297 * ... the one action must be a SELECT, ...
298 */
299 query = (Query *) linitial(action);
300 if (!is_instead ||
301 query->commandType != CMD_SELECT ||
302 query->utilityStmt != NULL ||
303 query->intoClause != NULL)
304 ereport(ERROR,
305 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
306 errmsg("rules on SELECT must have action INSTEAD SELECT")));
307
308 /*
309 * ... there can be no rule qual, ...
310 */
311 if (event_qual != NULL)
312 ereport(ERROR,
313 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
314 errmsg("event qualifications are not implemented for rules on SELECT")));
315
316 /*
317 * ... the targetlist of the SELECT action must exactly match the
318 * event relation, ...
319 */
320 checkRuleResultList(query->targetList,
321 RelationGetDescr(event_relation),
322 true);
323
324 /*
325 * ... there must not be another ON SELECT rule already ...
326 */
327 if (!replace && event_relation->rd_rules != NULL)
328 {
329 int i;
330
331 for (i = 0; i < event_relation->rd_rules->numLocks; i++)
332 {
333 RewriteRule *rule;
334
335 rule = event_relation->rd_rules->rules[i];
336 if (rule->event == CMD_SELECT)
337 ereport(ERROR,
338 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
339 errmsg("\"%s\" is already a view",
340 RelationGetRelationName(event_relation))));
341 }
342 }
343
344 /*
345 * ... and finally the rule must be named _RETURN.
346 */
347 if (strcmp(rulename, ViewSelectRuleName) != 0)
348 {
349 /*
350 * In versions before 7.3, the expected name was _RETviewname. For
351 * backwards compatibility with old pg_dump output, accept that
352 * and silently change it to _RETURN. Since this is just a quick
353 * backwards-compatibility hack, limit the number of characters
354 * checked to a few less than NAMEDATALEN; this saves having to
355 * worry about where a multibyte character might have gotten
356 * truncated.
357 */
358 if (strncmp(rulename, "_RET", 4) != 0 ||
359 strncmp(rulename + 4, RelationGetRelationName(event_relation),
360 NAMEDATALEN - 4 - 4) != 0)
361 ereport(ERROR,
362 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
363 errmsg("view rule for \"%s\" must be named \"%s\"",
364 RelationGetRelationName(event_relation),
365 ViewSelectRuleName)));
366 rulename = pstrdup(ViewSelectRuleName);
367 }
368
369 /*
370 * Are we converting a relation to a view?
371 *
372 * If so, check that the relation is empty because the storage for the
373 * relation is going to be deleted. Also insist that the rel not have
374 * any triggers, indexes, or child tables. (Note: these tests are
375 * too strict, because they will reject relations that once had such
376 * but don't anymore. But we don't really care, because this whole
377 * business of converting relations to views is just a kluge to allow
378 * loading ancient pg_dump files.)
379 */
380 if (event_relation->rd_rel->relkind != RELKIND_VIEW)
381 {
382 HeapScanDesc scanDesc;
383
384 scanDesc = heap_beginscan(event_relation, SnapshotNow, 0, NULL);
385 if (heap_getnext(scanDesc, ForwardScanDirection) != NULL)
386 ereport(ERROR,
387 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
388 errmsg("could not convert table \"%s\" to a view because it is not empty",
389 RelationGetRelationName(event_relation))));
390 heap_endscan(scanDesc);
391
392 if (event_relation->rd_rel->relhastriggers)
393 ereport(ERROR,
394 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
395 errmsg("could not convert table \"%s\" to a view because it has triggers",
396 RelationGetRelationName(event_relation)),
397 errhint("In particular, the table cannot be involved in any foreign key relationships.")));
398
399 if (event_relation->rd_rel->relhasindex)
400 ereport(ERROR,
401 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
402 errmsg("could not convert table \"%s\" to a view because it has indexes",
403 RelationGetRelationName(event_relation))));
404
405 if (event_relation->rd_rel->relhassubclass)
406 ereport(ERROR,
407 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
408 errmsg("could not convert table \"%s\" to a view because it has child tables",
409 RelationGetRelationName(event_relation))));
410
411 RelisBecomingView = true;
412 }
413 }
414 else
415 {
416 /*
417 * For non-SELECT rules, a RETURNING list can appear in at most one of
418 * the actions ... and there can't be any RETURNING list at all in a
419 * conditional or non-INSTEAD rule. (Actually, there can be at most
420 * one RETURNING list across all rules on the same event, but it seems
421 * best to enforce that at rule expansion time.) If there is a
422 * RETURNING list, it must match the event relation.
423 */
424 bool haveReturning = false;
425
426 foreach(l, action)
427 {
428 query = (Query *) lfirst(l);
429
430 if (!query->returningList)
431 continue;
432 if (haveReturning)
433 ereport(ERROR,
434 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
435 errmsg("cannot have multiple RETURNING lists in a rule")));
436 haveReturning = true;
437 if (event_qual != NULL)
438 ereport(ERROR,
439 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
440 errmsg("RETURNING lists are not supported in conditional rules")));
441 if (!is_instead)
442 ereport(ERROR,
443 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
444 errmsg("RETURNING lists are not supported in non-INSTEAD rules")));
445 checkRuleResultList(query->returningList,
446 RelationGetDescr(event_relation),
447 false);
448 }
449 }
450
451 /*
452 * This rule is allowed - prepare to install it.
453 */
454 event_attno = -1;
455
456 /* discard rule if it's null action and not INSTEAD; it's a no-op */
457 if (action != NIL || is_instead)
458 {
459 ruleId = InsertRule(rulename,
460 event_type,
461 event_relid,
462 event_attno,
463 is_instead,
464 event_qual,
465 action,
466 replace);
467
468 /*
469 * Set pg_class 'relhasrules' field TRUE for event relation. If
470 * appropriate, also modify the 'relkind' field to show that the
471 * relation is now a view.
472 *
473 * Important side effect: an SI notice is broadcast to force all
474 * backends (including me!) to update relcache entries with the new
475 * rule.
476 */
477 SetRelationRuleStatus(event_relid, true, RelisBecomingView);
478 }
479
480 /*
481 * IF the relation is becoming a view, delete the storage files associated
482 * with it. NB: we had better have AccessExclusiveLock to do this ...
483 *
484 * XXX what about getting rid of its TOAST table? For now, we don't.
485 */
486 if (RelisBecomingView)
487 RelationDropStorage(event_relation);
488
489 /* Close rel, but keep lock till commit... */
490 heap_close(event_relation, NoLock);
491 }
492
493 /*
494 * checkRuleResultList
495 * Verify that targetList produces output compatible with a tupledesc
496 *
497 * The targetList might be either a SELECT targetlist, or a RETURNING list;
498 * isSelect tells which. (This is mostly used for choosing error messages,
499 * but also we don't enforce column name matching for RETURNING.)
500 */
501 static void
502 checkRuleResultList(List *targetList, TupleDesc resultDesc, bool isSelect)
503 {
504 ListCell *tllist;
505 int i;
506
507 i = 0;
508 foreach(tllist, targetList)
509 {
510 TargetEntry *tle = (TargetEntry *) lfirst(tllist);
511 int32 tletypmod;
512 Form_pg_attribute attr;
513 char *attname;
514
515 /* resjunk entries may be ignored */
516 if (tle->resjunk)
517 continue;
518 i++;
519 if (i > resultDesc->natts)
520 ereport(ERROR,
521 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
522 isSelect ?
523 errmsg("SELECT rule's target list has too many entries") :
524 errmsg("RETURNING list has too many entries")));
525
526 attr = resultDesc->attrs[i - 1];
527 attname = NameStr(attr->attname);
528
529 /*
530 * Disallow dropped columns in the relation. This won't happen in the
531 * cases we actually care about (namely creating a view via CREATE
532 * TABLE then CREATE RULE, or adding a RETURNING rule to a view).
533 * Trying to cope with it is much more trouble than it's worth,
534 * because we'd have to modify the rule to insert dummy NULLs at the
535 * right positions.
536 */
537 if (attr->attisdropped)
538 ereport(ERROR,
539 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
540 errmsg("cannot convert relation containing dropped columns to view")));
541
542 if (isSelect && strcmp(tle->resname, attname) != 0)
543 ereport(ERROR,
544 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
545 errmsg("SELECT rule's target entry %d has different column name from \"%s\"", i, attname)));
546
547 if (attr->atttypid != exprType((Node *) tle->expr))
548 ereport(ERROR,
549 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
550 isSelect ?
551 errmsg("SELECT rule's target entry %d has different type from column \"%s\"",
552 i, attname) :
553 errmsg("RETURNING list's entry %d has different type from column \"%s\"",
554 i, attname)));
555
556 /*
557 * Allow typmods to be different only if one of them is -1, ie,
558 * "unspecified". This is necessary for cases like "numeric", where
559 * the table will have a filled-in default length but the select
560 * rule's expression will probably have typmod = -1.
561 */
562 tletypmod = exprTypmod((Node *) tle->expr);
563 if (attr->atttypmod != tletypmod &&
564 attr->atttypmod != -1 && tletypmod != -1)
565 ereport(ERROR,
566 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
567 isSelect ?
568 errmsg("SELECT rule's target entry %d has different size from column \"%s\"",
569 i, attname) :
570 errmsg("RETURNING list's entry %d has different size from column \"%s\"",
571 i, attname)));
572 }
573
574 if (i != resultDesc->natts)
575 ereport(ERROR,
576 (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
577 isSelect ?
578 errmsg("SELECT rule's target list has too few entries") :
579 errmsg("RETURNING list has too few entries")));
580 }
581
582 /*
583 * setRuleCheckAsUser
584 * Recursively scan a query or expression tree and set the checkAsUser
585 * field to the given userid in all rtable entries.
586 *
587 * Note: for a view (ON SELECT rule), the checkAsUser field of the *OLD*
588 * RTE entry will be overridden when the view rule is expanded, and the
589 * checkAsUser field of the *NEW* entry is irrelevant because that entry's
590 * requiredPerms bits will always be zero. However, for other types of rules
591 * it's important to set these fields to match the rule owner. So we just set
592 * them always.
593 */
594 void
595 setRuleCheckAsUser(Node *node, Oid userid)
596 {
597 (void) setRuleCheckAsUser_walker(node, &userid);
598 }
599
600 static bool
601 setRuleCheckAsUser_walker(Node *node, Oid *context)
602 {
603 if (node == NULL)
604 return false;
605 if (IsA(node, Query))
606 {
607 setRuleCheckAsUser_Query((Query *) node, *context);
608 return false;
609 }
610 return expression_tree_walker(node, setRuleCheckAsUser_walker,
611 (void *) context);
612 }
613
614 static void
615 setRuleCheckAsUser_Query(Query *qry, Oid userid)
616 {
617 ListCell *l;
618
619 /* Set all the RTEs in this query node */
620 foreach(l, qry->rtable)
621 {
622 RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
623
624 if (rte->rtekind == RTE_SUBQUERY)
625 {
626 /* Recurse into subquery in FROM */
627 setRuleCheckAsUser_Query(rte->subquery, userid);
628 }
629 else
630 rte->checkAsUser = userid;
631 }
632
633 /* Recurse into subquery-in-WITH */
634 foreach(l, qry->cteList)
635 {
636 CommonTableExpr *cte = (CommonTableExpr *) lfirst(l);
637
638 setRuleCheckAsUser_Query((Query *) cte->ctequery, userid);
639 }
640
641 /* If there are sublinks, search for them and process their RTEs */
642 if (qry->hasSubLinks)
643 query_tree_walker(qry, setRuleCheckAsUser_walker, (void *) &userid,
644 QTW_IGNORE_RC_SUBQUERIES);
645 }
646
647
648 /*
649 * Change the firing semantics of an existing rule.
650 */
651 void
652 EnableDisableRule(Relation rel, const char *rulename,
653 char fires_when)
654 {
655 Relation pg_rewrite_desc;
656 Oid owningRel = RelationGetRelid(rel);
657 Oid eventRelationOid;
658 HeapTuple ruletup;
659 bool changed = false;
660
661 /*
662 * Find the rule tuple to change.
663 */
664 pg_rewrite_desc = heap_open(RewriteRelationId, RowExclusiveLock);
665 ruletup = SearchSysCacheCopy(RULERELNAME,
666 ObjectIdGetDatum(owningRel),
667 PointerGetDatum(rulename),
668 0, 0);
669 if (!HeapTupleIsValid(ruletup))
670 ereport(ERROR,
671 (errcode(ERRCODE_UNDEFINED_OBJECT),
672 errmsg("rule \"%s\" for relation \"%s\" does not exist",
673 rulename, get_rel_name(owningRel))));
674
675 /*
676 * Verify that the user has appropriate permissions.
677 */
678 eventRelationOid = ((Form_pg_rewrite) GETSTRUCT(ruletup))->ev_class;
679 Assert(eventRelationOid == owningRel);
680 if (!pg_class_ownercheck(eventRelationOid, GetUserId()))
681 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
682 get_rel_name(eventRelationOid));
683
684 /*
685 * Change ev_enabled if it is different from the desired new state.
686 */
687 if (DatumGetChar(((Form_pg_rewrite) GETSTRUCT(ruletup))->ev_enabled) !=
688 fires_when)
689 {
690 ((Form_pg_rewrite) GETSTRUCT(ruletup))->ev_enabled =
691 CharGetDatum(fires_when);
692 simple_heap_update(pg_rewrite_desc, &ruletup->t_self, ruletup);
693
694 /* keep system catalog indexes current */
695 CatalogUpdateIndexes(pg_rewrite_desc, ruletup);
696
697 changed = true;
698 }
699
700 heap_freetuple(ruletup);
701 heap_close(pg_rewrite_desc, RowExclusiveLock);
702
703 /*
704 * If we changed anything, broadcast a SI inval message to force each
705 * backend (including our own!) to rebuild relation's relcache entry.
706 * Otherwise they will fail to apply the change promptly.
707 */
708 if (changed)
709 CacheInvalidateRelcache(rel);
710 }
711
712
713 /*
714 * Rename an existing rewrite rule.
715 *
716 * This is unused code at the moment. Note that it lacks a permissions check.
717 */
718 #ifdef NOT_USED
719 void
720 RenameRewriteRule(Oid owningRel, const char *oldName,
721 const char *newName)
722 {
723 Relation pg_rewrite_desc;
724 HeapTuple ruletup;
725
726 pg_rewrite_desc = heap_open(RewriteRelationId, RowExclusiveLock);
727
728 ruletup = SearchSysCacheCopy(RULERELNAME,
729 ObjectIdGetDatum(owningRel),
730 PointerGetDatum(oldName),
731 0, 0);
732 if (!HeapTupleIsValid(ruletup))
733 ereport(ERROR,
734 (errcode(ERRCODE_UNDEFINED_OBJECT),
735 errmsg("rule \"%s\" for relation \"%s\" does not exist",
736 oldName, get_rel_name(owningRel))));
737
738 /* should not already exist */
739 if (IsDefinedRewriteRule(owningRel, newName))
740 ereport(ERROR,
741 (errcode(ERRCODE_DUPLICATE_OBJECT),
742 errmsg("rule \"%s\" for relation \"%s\" already exists",
743 newName, get_rel_name(owningRel))));
744
745 namestrcpy(&(((Form_pg_rewrite) GETSTRUCT(ruletup))->rulename), newName);
746
747 simple_heap_update(pg_rewrite_desc, &ruletup->t_self, ruletup);
748
749 /* keep system catalog indexes current */
750 CatalogUpdateIndexes(pg_rewrite_desc, ruletup);
751
752 heap_freetuple(ruletup);
753 heap_close(pg_rewrite_desc, RowExclusiveLock);
754 }
755
756 #endif
PostgreSQL from CVS