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/*-------------------------------------------------------------------------
*
* rewriteRemove.c
* routines for removing rewrite rules
*
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/rewrite/rewriteRemove.c,v 1.67 2006/10/03 21:21:36 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/pg_rewrite.h"
#include "miscadmin.h"
#include "rewrite/rewriteRemove.h"
#include "rewrite/rewriteSupport.h"
#include "utils/acl.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
/*
* RemoveRewriteRule
*
* Delete a rule given its name.
*/
void
RemoveRewriteRule(Oid owningRel, const char *ruleName, DropBehavior behavior,
bool missing_ok)
{
HeapTuple tuple;
Oid eventRelationOid;
ObjectAddress object;
/*
* Find the tuple for the target rule.
*/
tuple = SearchSysCache(RULERELNAME,
ObjectIdGetDatum(owningRel),
PointerGetDatum(ruleName),
0, 0);
/*
* complain if no rule with such name exists
*/
if (!HeapTupleIsValid(tuple))
{
if (! missing_ok)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("rule \"%s\" for relation \"%s\" does not exist",
ruleName, get_rel_name(owningRel))));
else
ereport(NOTICE,
(errmsg("rule \"%s\" for relation \"%s\" does not exist, skipping",
ruleName, get_rel_name(owningRel))));
return;
}
/*
* Verify user has appropriate permissions.
*/
eventRelationOid = ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class;
Assert(eventRelationOid == owningRel);
if (!pg_class_ownercheck(eventRelationOid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
get_rel_name(eventRelationOid));
/*
* Do the deletion
*/
object.classId = RewriteRelationId;
object.objectId = HeapTupleGetOid(tuple);
object.objectSubId = 0;
ReleaseSysCache(tuple);
performDeletion(&object, behavior);
}
/*
* Guts of rule deletion.
*/
void
RemoveRewriteRuleById(Oid ruleOid)
{
Relation RewriteRelation;
ScanKeyData skey[1];
SysScanDesc rcscan;
Relation event_relation;
HeapTuple tuple;
Oid eventRelationOid;
bool hasMoreRules;
/*
* Open the pg_rewrite relation.
*/
RewriteRelation = heap_open(RewriteRelationId, RowExclusiveLock);
/*
* Find the tuple for the target rule.
*/
ScanKeyInit(&skey[0],
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(ruleOid));
rcscan = systable_beginscan(RewriteRelation, RewriteOidIndexId, true,
SnapshotNow, 1, skey);
tuple = systable_getnext(rcscan);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "could not find tuple for rule %u", ruleOid);
/*
* We had better grab AccessExclusiveLock so that we know no other rule
* additions/deletions are going on for this relation. Else we cannot set
* relhasrules correctly. Besides, we don't want to be changing the
* ruleset while queries are executing on the rel.
*/
eventRelationOid = ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class;
event_relation = heap_open(eventRelationOid, AccessExclusiveLock);
hasMoreRules = event_relation->rd_rules != NULL &&
event_relation->rd_rules->numLocks > 1;
/*
* Now delete the pg_rewrite tuple for the rule
*/
simple_heap_delete(RewriteRelation, &tuple->t_self);
systable_endscan(rcscan);
heap_close(RewriteRelation, RowExclusiveLock);
/*
* Set pg_class 'relhasrules' field correctly for event relation.
*
* Important side effect: an SI notice is broadcast to force all backends
* (including me!) to update relcache entries with the new rule set.
* Therefore, must do this even if relhasrules is still true!
*/
SetRelationRuleStatus(eventRelationOid, hasMoreRules, false);
/* Close rel, but keep lock till commit... */
heap_close(event_relation, NoLock);
}
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