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/*-------------------------------------------------------------------------
*
* rewriteSupport.c
*
*
* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/rewrite/rewriteSupport.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "access/table.h"
#include "catalog/indexing.h"
#include "catalog/pg_rewrite.h"
#include "rewrite/rewriteSupport.h"
#include "utils/fmgroids.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/syscache.h"
/*
* Is there a rule by the given name?
*/
bool
IsDefinedRewriteRule(Oid owningRel, const char *ruleName)
{
return SearchSysCacheExists2(RULERELNAME,
ObjectIdGetDatum(owningRel),
PointerGetDatum(ruleName));
}
/*
* SetRelationRuleStatus
* Set the value of the relation's relhasrules field in pg_class.
*
* 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)
{
Relation relationRelation;
HeapTuple tuple;
Form_pg_class classForm;
/*
* Find the tuple to update in pg_class, using syscache for the lookup.
*/
relationRelation = table_open(RelationRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relationId));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", relationId);
classForm = (Form_pg_class) GETSTRUCT(tuple);
if (classForm->relhasrules != relHasRules)
{
/* Do the update */
classForm->relhasrules = relHasRules;
CatalogTupleUpdate(relationRelation, &tuple->t_self, tuple);
}
else
{
/* no need to change tuple, but force relcache rebuild anyway */
CacheInvalidateRelcacheByTuple(tuple);
}
heap_freetuple(tuple);
table_close(relationRelation, RowExclusiveLock);
}
/*
* Find rule oid.
*
* If missing_ok is false, throw an error if rule name not found. If
* true, just return InvalidOid.
*/
Oid
get_rewrite_oid(Oid relid, const char *rulename, bool missing_ok)
{
HeapTuple tuple;
Form_pg_rewrite ruleform;
Oid ruleoid;
/* Find the rule's pg_rewrite tuple, get its OID */
tuple = SearchSysCache2(RULERELNAME,
ObjectIdGetDatum(relid),
PointerGetDatum(rulename));
if (!HeapTupleIsValid(tuple))
{
if (missing_ok)
return InvalidOid;
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("rule \"%s\" for relation \"%s\" does not exist",
rulename, get_rel_name(relid))));
}
ruleform = (Form_pg_rewrite) GETSTRUCT(tuple);
Assert(relid == ruleform->ev_class);
ruleoid = ruleform->oid;
ReleaseSysCache(tuple);
return ruleoid;
}
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