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/*-------------------------------------------------------------------------
*
* rewriteSupport.c
*
*
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/rewrite/rewriteSupport.c,v 1.66 2008/06/19 00:46:05 alvherre Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/heapam.h"
#include "catalog/indexing.h"
#include "catalog/pg_class.h"
#include "rewrite/rewriteSupport.h"
#include "utils/inval.h"
#include "utils/syscache.h"
/*
* Is there a rule by the given name?
*/
bool
IsDefinedRewriteRule(Oid owningRel, const char *ruleName)
{
return SearchSysCacheExists(RULERELNAME,
ObjectIdGetDatum(owningRel),
PointerGetDatum(ruleName),
0, 0);
}
/*
* SetRelationRuleStatus
* Set the value of the relation's relhasrules field in pg_class;
* if the relation is becoming a view, also adjust its relkind.
*
* NOTE: caller must be holding an appropriate lock on the relation.
*
* NOTE: an important side-effect of this operation is that an SI invalidation
* message is sent out to all backends --- including me --- causing relcache
* entries to be flushed or updated with the new set of rules for the table.
* This must happen even if we find that no change is needed in the pg_class
* row.
*/
void
SetRelationRuleStatus(Oid relationId, bool relHasRules,
bool relIsBecomingView)
{
Relation relationRelation;
HeapTuple tuple;
Form_pg_class classForm;
/*
* Find the tuple to update in pg_class, using syscache for the lookup.
*/
relationRelation = heap_open(RelationRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopy(RELOID,
ObjectIdGetDatum(relationId),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", relationId);
classForm = (Form_pg_class) GETSTRUCT(tuple);
if (classForm->relhasrules != relHasRules ||
(relIsBecomingView && classForm->relkind != RELKIND_VIEW))
{
/* Do the update */
classForm->relhasrules = relHasRules;
if (relIsBecomingView)
classForm->relkind = RELKIND_VIEW;
simple_heap_update(relationRelation, &tuple->t_self, tuple);
/* Keep the catalog indexes up to date */
CatalogUpdateIndexes(relationRelation, tuple);
}
else
{
/* no need to change tuple, but force relcache rebuild anyway */
CacheInvalidateRelcacheByTuple(tuple);
}
heap_freetuple(tuple);
heap_close(relationRelation, RowExclusiveLock);
}
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