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rewriteRemove.c
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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
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 }
#define RewriteOidIndexId
Definition: indexing.h:218
void table_close(Relation relation, LOCKMODE lockmode)
Definition: table.c:133
void systable_endscan(SysScanDesc sysscan)
Definition: genam.c:525
#define GETSTRUCT(TUP)
Definition: htup_details.h:655
void CatalogTupleDelete(Relation heapRel, ItemPointer tid)
Definition: indexing.c:269
unsigned int Oid
Definition: postgres_ext.h:31
SysScanDesc systable_beginscan(Relation heapRelation, Oid indexId, bool indexOK, Snapshot snapshot, int nkeys, ScanKey key)
Definition: genam.c:352
HeapTuple systable_getnext(SysScanDesc sysscan)
Definition: genam.c:444
#define ObjectIdGetDatum(X)
Definition: postgres.h:507
#define ERROR
Definition: elog.h:43
ItemPointerData t_self
Definition: htup.h:65
#define NoLock
Definition: lockdefs.h:34
#define RowExclusiveLock
Definition: lockdefs.h:38
#define HeapTupleIsValid(tuple)
Definition: htup.h:78
FormData_pg_rewrite * Form_pg_rewrite
Definition: pg_rewrite.h:52
void CacheInvalidateRelcache(Relation relation)
Definition: inval.c:1270
#define AccessExclusiveLock
Definition: lockdefs.h:45
void RemoveRewriteRuleById(Oid ruleOid)
Definition: rewriteRemove.c:37
#define elog(elevel,...)
Definition: elog.h:228
void ScanKeyInit(ScanKey entry, AttrNumber attributeNumber, StrategyNumber strategy, RegProcedure procedure, Datum argument)
Definition: scankey.c:76
Relation table_open(Oid relationId, LOCKMODE lockmode)
Definition: table.c:39
#define BTEqualStrategyNumber
Definition: stratnum.h:31