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/*-------------------------------------------------------------------------
*
* rewriteRemove.c--
* routines for removing rewrite rules
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteRemove.c,v 1.17 1998/09/01 03:24:57 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "fmgr.h" /* for F_NAMEEQ */
#include "access/heapam.h" /* heap AM calls defined here */
#include "access/skey.h"
#include "catalog/catname.h" /* for RewriteRelationName */
#include "catalog/pg_rewrite.h"
#include "utils/syscache.h"
#include "rewrite/rewriteRemove.h" /* where the decls go */
#include "rewrite/rewriteSupport.h"
/*-----------------------------------------------------------------------
* RewriteGetRuleEventRel
*-----------------------------------------------------------------------
*/
char *
RewriteGetRuleEventRel(char *rulename)
{
HeapTuple htup;
Oid eventrel;
htup = SearchSysCacheTuple(REWRITENAME,
PointerGetDatum(rulename),
0, 0, 0);
if (!HeapTupleIsValid(htup))
elog(ERROR, "RewriteGetRuleEventRel: rule \"%s\" not found",
rulename);
eventrel = ((Form_pg_rewrite) GETSTRUCT(htup))->ev_class;
htup = SearchSysCacheTuple(RELOID,
PointerGetDatum(eventrel),
0, 0, 0);
if (!HeapTupleIsValid(htup))
elog(ERROR, "RewriteGetRuleEventRel: class %d not found",
eventrel);
return ((Form_pg_class) GETSTRUCT(htup))->relname.data;
}
/* ----------------------------------------------------------------
*
* RemoveRewriteRule
*
* Delete a rule given its rulename.
*
* There are three steps.
* 1) Find the corresponding tuple in 'pg_rewrite' relation.
* Find the rule Id (i.e. the Oid of the tuple) and finally delete
* the tuple.
* 3) Delete the locks from the 'pg_class' relation.
*
*
* ----------------------------------------------------------------
*/
void
RemoveRewriteRule(char *ruleName)
{
Relation RewriteRelation = NULL;
HeapTuple tuple = NULL;
Oid ruleId = (Oid) 0;
Oid eventRelationOid = (Oid) NULL;
Datum eventRelationOidDatum = (Datum) NULL;
bool isNull = false;
/*
* Open the pg_rewrite relation.
*/
RewriteRelation = heap_openr(RewriteRelationName);
/*
* Scan the RuleRelation ('pg_rewrite') until we find a tuple
*/
tuple = SearchSysCacheTupleCopy(REWRITENAME,
PointerGetDatum(ruleName),
0, 0, 0);
/*
* complain if no rule with such name existed
*/
if (!HeapTupleIsValid(tuple))
{
heap_close(RewriteRelation);
elog(ERROR, "No rule with name = '%s' was found.\n", ruleName);
}
/*
* Store the OID of the rule (i.e. the tuple's OID) and the event
* relation's OID
*/
ruleId = tuple->t_oid;
eventRelationOidDatum = heap_getattr(tuple,
Anum_pg_rewrite_ev_class,
RelationGetDescr(RewriteRelation),
&isNull);
if (isNull)
{
/* XXX strange!!! */
pfree(tuple);
elog(ERROR, "RemoveRewriteRule: null event target relation!");
}
eventRelationOid = DatumGetObjectId(eventRelationOidDatum);
/*
* Now delete the relation level locks from the updated relation.
* (Make sure we do this before we remove the rule from pg_rewrite.
* Otherwise, heap_openr on eventRelationOid which reads pg_rwrite for
* the rules will fail.)
*/
prs2_deleteFromRelation(eventRelationOid, ruleId);
/*
* Now delete the tuple...
*/
heap_delete(RewriteRelation, &tuple->t_ctid);
pfree(tuple);
heap_close(RewriteRelation);
}
/*
* RelationRemoveRules -
* removes all rules associated with the relation when the relation is
* being removed.
*/
void
RelationRemoveRules(Oid relid)
{
Relation RewriteRelation = NULL;
HeapScanDesc scanDesc = NULL;
ScanKeyData scanKeyData;
HeapTuple tuple = NULL;
/*
* Open the pg_rewrite relation.
*/
RewriteRelation = heap_openr(RewriteRelationName);
/*
* Scan the RuleRelation ('pg_rewrite') for all the tuples that has
* the same ev_class as relid (the relation to be removed).
*/
ScanKeyEntryInitialize(&scanKeyData,
0,
Anum_pg_rewrite_ev_class,
F_OIDEQ,
ObjectIdGetDatum(relid));
scanDesc = heap_beginscan(RewriteRelation,
0, SnapshotNow, 1, &scanKeyData);
while (HeapTupleIsValid(tuple = heap_getnext(scanDesc, 0)))
heap_delete(RewriteRelation, &tuple->t_ctid);
heap_endscan(scanDesc);
heap_close(RewriteRelation);
}
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