1 /*-------------------------------------------------------------------------
2 *
3 * rewriteRemove.c
4 * routines for removing rewrite rules
5 *
6 * Portions Copyright (c) 1996-2019, 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/htup_details.h"
19 #include "access/sysattr.h"
20 #include "access/table.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
33 /*
34 * Guts of rule deletion.
35 */
36 void
RemoveRewriteRuleById(Oid ruleOid)37 RemoveRewriteRuleById(Oid ruleOid)
38 {
39 Relation RewriteRelation;
40 ScanKeyData skey[1];
41 SysScanDesc rcscan;
42 Relation event_relation;
43 HeapTuple tuple;
44 Oid eventRelationOid;
45
46 /*
47 * Open the pg_rewrite relation.
48 */
49 RewriteRelation = table_open(RewriteRelationId, RowExclusiveLock);
50
51 /*
52 * Find the tuple for the target rule.
53 */
54 ScanKeyInit(&skey[0],
55 Anum_pg_rewrite_oid,
56 BTEqualStrategyNumber, F_OIDEQ,
57 ObjectIdGetDatum(ruleOid));
58
59 rcscan = systable_beginscan(RewriteRelation, RewriteOidIndexId, true,
60 NULL, 1, skey);
61
62 tuple = systable_getnext(rcscan);
63
64 if (!HeapTupleIsValid(tuple))
65 elog(ERROR, "could not find tuple for rule %u", ruleOid);
66
67 /*
68 * We had better grab AccessExclusiveLock to ensure that no queries are
69 * going on that might depend on this rule. (Note: a weaker lock would
70 * suffice if it's not an ON SELECT rule.)
71 */
72 eventRelationOid = ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class;
73 event_relation = table_open(eventRelationOid, AccessExclusiveLock);
74
75 /*
76 * Now delete the pg_rewrite tuple for the rule
77 */
78 CatalogTupleDelete(RewriteRelation, &tuple->t_self);
79
80 systable_endscan(rcscan);
81
82 table_close(RewriteRelation, RowExclusiveLock);
83
84 /*
85 * Issue shared-inval notice to force all backends (including me!) to
86 * update relcache entries with the new rule set.
87 */
88 CacheInvalidateRelcache(event_relation);
89
90 /* Close rel, but keep lock till commit... */
91 table_close(event_relation, NoLock);
92 }
93