Add support for ALTER TABLE IF EXISTS ... RENAME CONSTRAINT

Also add regression test.  Previously this was documented to work, but
didn't.

1 files changed, 8 insertions, 1 deletions

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index a9f79431e5c..32e19c5e4fc 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -2497,9 +2497,16 @@ RenameConstraint(RenameStmt *stmt)
 	{
 		/* lock level taken here should match rename_constraint_internal */
 		relid = RangeVarGetRelidExtended(stmt->relation, AccessExclusiveLock,
-										 false, false,
+										 stmt->missing_ok, false,
 										 RangeVarCallbackForRenameAttribute,
 										 NULL);
+		if (!OidIsValid(relid))
+		{
+			ereport(NOTICE,
+					(errmsg("relation \"%s\" does not exist, skipping",
+							stmt->relation->relname)));
+			return InvalidObjectAddress;
+		}
 	}
 
 	return