1 /*-------------------------------------------------------------------------
2 *
3 * rewriteRemove.c
4 * routines for removing rewrite rules
5 *
6 * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * src/backend/rewrite/rewriteRemove.c
12 *
13 *-------------------------------------------------------------------------
14 */
15 #include "postgres.h"
16
17 #include "access/genam.h"
18 #include "access/heapam.h"
19 #include "access/htup_details.h"
20 #include "access/sysattr.h"
21 #include "catalog/dependency.h"
22 #include "catalog/indexing.h"
23 #include "catalog/namespace.h"
24 #include "catalog/pg_rewrite.h"
25 #include "miscadmin.h"
26 #include "rewrite/rewriteRemove.h"
27 #include "utils/acl.h"
28 #include "utils/fmgroids.h"
29 #include "utils/inval.h"
30 #include "utils/lsyscache.h"
31 #include "utils/syscache.h"
32 #include "utils/tqual.h"
33
34 /*
35 * Guts of rule deletion.
36 */
37 void
RemoveRewriteRuleById(Oid ruleOid)38 RemoveRewriteRuleById(Oid ruleOid)
39 {
40 Relation RewriteRelation;
41 ScanKeyData skey[1];
42 SysScanDesc rcscan;
43 Relation event_relation;
44 HeapTuple tuple;
45 Oid eventRelationOid;
46
47 /*
48 * Open the pg_rewrite relation.
49 */
50 RewriteRelation = heap_open(RewriteRelationId, RowExclusiveLock);
51
52 /*
53 * Find the tuple for the target rule.
54 */
55 ScanKeyInit(&skey[0],
56 ObjectIdAttributeNumber,
57 BTEqualStrategyNumber, F_OIDEQ,
58 ObjectIdGetDatum(ruleOid));
59
60 rcscan = systable_beginscan(RewriteRelation, RewriteOidIndexId, true,
61 NULL, 1, skey);
62
63 tuple = systable_getnext(rcscan);
64
65 if (!HeapTupleIsValid(tuple))
66 elog(ERROR, "could not find tuple for rule %u", ruleOid);
67
68 /*
69 * We had better grab AccessExclusiveLock to ensure that no queries are
70 * going on that might depend on this rule. (Note: a weaker lock would
71 * suffice if it's not an ON SELECT rule.)
72 */
73 eventRelationOid = ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class;
74 event_relation = heap_open(eventRelationOid, AccessExclusiveLock);
75
76 /*
77 * Now delete the pg_rewrite tuple for the rule
78 */
79 CatalogTupleDelete(RewriteRelation, &tuple->t_self);
80
81 systable_endscan(rcscan);
82
83 heap_close(RewriteRelation, RowExclusiveLock);
84
85 /*
86 * Issue shared-inval notice to force all backends (including me!) to
87 * update relcache entries with the new rule set.
88 */
89 CacheInvalidateRelcache(event_relation);
90
91 /* Close rel, but keep lock till commit... */
92 heap_close(event_relation, NoLock);
93 }
94