Revert patch becaues of locking concerns:

Allow ALTER TABLE ... ALTER CONSTRAINT ... RENAME

Joachim Wieland

1 files changed, 1 insertions, 189 deletions

diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index 6e89d6832c2..2a11674683b 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/pg_constraint.c,v 1.29 2006/02/11 22:17:18 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/pg_constraint.c,v 1.30 2006/02/12 19:11:01 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -664,191 +664,3 @@ AlterConstraintNamespaces(Oid ownerId, Oid oldNspId,
 
 	heap_close(conRel, RowExclusiveLock);
 }
-
-
-/*
- * RenameConstraint
- *		Rename a single constraint record
- *		conId: The OID of the constraint to rename
- *		newName: The new name of the constraint
- *		implicitRename: is this an implicit rename? If so, we will issue
- *		                a notice about the implicit rename
- *		cmdName: the command that triggered the rename for the "implicitly
- *		         renames" notice message
- */
-void
-RenameConstraint(Oid conId, const char* newName,
-				 bool implicitRename, const char* cmdName)
-{
-	Relation			conRel;
-	ScanKeyData 		key[1];
-	SysScanDesc 		scan;
-	HeapTuple 			tup;
-	NameData			newNameData;
-	Relation			rel;
-	Oid					relId;
-	Oid					nspOid;
-	Form_pg_constraint	conform;
-
-	/* before reading the tuple, lock the table it constraints in
-	 * AccessExclusiveLock mode. Otherwise, if we read it before locking this
-	 * table, the tuple might be changed by another transaction and our copy
-	 * would be out of date
-	 */
-	relId = GetConstraintRelationId(conId);
-	if (!OidIsValid(relId))
-	{
-		ereport(ERROR,
-				(errcode(ERRCODE_UNDEFINED_OBJECT),
-				 errmsg("constraint with OID %d does not exist", conId)));
-	}
-
-	rel = relation_open(relId, AccessExclusiveLock);
-	nspOid = get_rel_namespace(relId);
-
-	conRel = heap_open(ConstraintRelationId, RowExclusiveLock);
-
-	ScanKeyInit(&key[0],
-				ObjectIdAttributeNumber,
-				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(conId));
-
-	scan = systable_beginscan(conRel, ConstraintOidIndexId, true,
-							  SnapshotNow, 1, key);
-	if (!HeapTupleIsValid((tup = systable_getnext(scan))))
-	{
-		ereport(ERROR,
-				(errcode(ERRCODE_UNDEFINED_OBJECT),
-				 errmsg("constraint with OID %d does not exist", conId)));
-	}
-
-	conform = (Form_pg_constraint) GETSTRUCT(tup);
-
-	if (ConstraintNameIsUsed(CONSTRAINT_RELATION,
-							 conform->conrelid,
-							 get_rel_namespace(conform->conrelid),
-							 newName))
-	{
-		ereport(ERROR,
-				(errcode(ERRCODE_DUPLICATE_OBJECT),
-				 errmsg("constraint \"%s\" for relation \"%s\" already exists",
-						newName,
-						RelationGetRelationName(rel))));
-	}
-	tup = heap_copytuple(tup);
-	conform = (Form_pg_constraint) GETSTRUCT(tup);
-
-	if (implicitRename && cmdName)
-	{
-		ereport(NOTICE,
-				(errmsg("%s will implicitly rename constraint "
-						"\"%s\" to \"%s\" on table \"%s.%s\"",
-					cmdName,
-					NameStr(conform->conname),
-					newName,
-					get_namespace_name(nspOid),
-					RelationGetRelationName(rel))));
-	}
-
-	namestrcpy(&newNameData, newName);
-	conform->conname = newNameData;
-
-	simple_heap_update(conRel, &tup->t_self, tup);
-	CatalogUpdateIndexes(conRel, tup);
-	heap_freetuple(tup);
-
-	systable_endscan(scan);
-	heap_close(conRel, RowExclusiveLock);
-
-	/* close relation but hold lock until end of transaction */
-	relation_close(rel, NoLock);
-}
-
-
-/* GetRelationConstraintOid
- *
- * Get the contraint OID by the relation Id of the relation it constraints and
- * this relations' name. We need this function in order to rename a constraint.
- * This is done via "ALTER TABLE ... ALTER CONSTRAINT name" and the parser
- * gives us the relation this constraint is defined on as well as the
- * constraint's name.
- *
- * The function returns:
- *
- *  - the unique OID of the constraint if the constraint could be found
- *  - the invalid OID if the constraint was not found
- *
- */
-Oid GetRelationConstraintOid(Oid relId, const char* name)
-{
-	Relation		conRel;
-	ScanKeyData 	key[1];
-	SysScanDesc 	scan;
-	HeapTuple 		tup;
-	Oid				conId = InvalidOid;
-
-	/* we don't change data, so an AccessShareLock is enough */
-	conRel = heap_open(ConstraintRelationId, AccessShareLock);
-
-	ScanKeyInit(&key[0],
-				Anum_pg_constraint_conrelid,
-				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(relId));
-
-	scan = systable_beginscan(conRel, ConstraintRelidIndexId, true,
-							  SnapshotNow, 1, key);
-
-	while (HeapTupleIsValid((tup = systable_getnext(scan))))
-	{
-		Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tup);
-		if (pg_strcasecmp(name, NameStr(con->conname)) == 0)
-		{
-			conId = HeapTupleGetOid(tup);
-			Assert(OidIsValid(conId));
-		}
-	}
-
-	systable_endscan(scan);
-	heap_close(conRel, AccessShareLock);
-
-	return conId;
-}
-
-
-/* GetConstraintRelationId
- *
- * Gets the OID of the relation where the constraint is defined on or the
- * invalid OID if the constraint cannot be found.
- */
-Oid GetConstraintRelationId(Oid conId)
-{
-	Relation		conRel;
-	ScanKeyData 	key[1];
-	SysScanDesc 	scan;
-	HeapTuple 		tup;
-	Oid				relId = InvalidOid;
-
-	/* we don't change data, so an AccessShareLock is enough */
-	conRel = heap_open(ConstraintRelationId, AccessShareLock);
-
-	ScanKeyInit(&key[0],
-				ObjectIdAttributeNumber,
-				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(conId));
-
-	scan = systable_beginscan(conRel, ConstraintOidIndexId, true,
-							  SnapshotNow, 1, key);
-
-	if (HeapTupleIsValid((tup = systable_getnext(scan))))
-	{
-		Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tup);
-		relId = con->conrelid;
-		Assert(OidIsValid(relId));
-	}
-
-	systable_endscan(scan);
-	heap_close(conRel, AccessShareLock);
-
-	return relId;
-}
-