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/*-------------------------------------------------------------------------
*
* rewriteRemove.c
* routines for removing rewrite rules
*
* Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/rewrite/rewriteRemove.c,v 1.76 2009/01/22 17:27:54 petere Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "access/sysattr.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/pg_rewrite.h"
#include "miscadmin.h"
#include "rewrite/rewriteRemove.h"
#include "utils/acl.h"
#include "utils/fmgroids.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/syscache.h"
#include "utils/tqual.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);
}
/*
* RemoveAutomaticRulesOnEvent
*
* This will delete automatic rules, if any exist, on the event in the
* relation.
*/
void
RemoveAutomaticRulesOnEvent(Relation rel, CmdType event_type)
{
RuleLock *rulelocks = rel->rd_rules;
int i;
/* If there are no rules on the relation, waste no more time. */
if (rulelocks == NULL)
return;
/*
* Look at all rules looking for the ones that are on the event
* and are automatic.
*/
for (i = 0; i < rulelocks->numLocks; i++)
{
RewriteRule *oneLock = rulelocks->rules[i];
if (oneLock->event == event_type && oneLock->is_auto)
{
RemoveRewriteRuleById(oneLock->ruleId);
elog(DEBUG1, "removing automatic rule with OID %u\n",
oneLock->ruleId);
deleteDependencyRecordsFor(RewriteRelationId, oneLock->ruleId);
}
}
}
/*
* Guts of rule deletion.
*/
void
RemoveRewriteRuleById(Oid ruleOid)
{
Relation RewriteRelation;
ScanKeyData skey[1];
SysScanDesc rcscan;
Relation event_relation;
HeapTuple tuple;
Oid eventRelationOid;
/*
* 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 to ensure that no queries
* are going on that might depend on this rule. (Note: a weaker lock
* would suffice if it's not an ON SELECT rule.)
*/
eventRelationOid = ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class;
event_relation = heap_open(eventRelationOid, AccessExclusiveLock);
/*
* Now delete the pg_rewrite tuple for the rule
*/
simple_heap_delete(RewriteRelation, &tuple->t_self);
systable_endscan(rcscan);
heap_close(RewriteRelation, RowExclusiveLock);
/*
* Issue shared-inval notice to force all backends (including me!) to
* update relcache entries with the new rule set.
*/
CacheInvalidateRelcache(event_relation);
/* Close rel, but keep lock till commit... */
heap_close(event_relation, NoLock);
}
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