Fix compiler warning and add some more comments

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 49a73707bca29d538171d10e713ea4903a763388..60f8b7f26c5a05ff2d7efe8e5e865a19d50e1044 100644 (file)
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -5924,6 +5924,11 @@ ATExecAddIdentity(Relation rel, const char *colName,
        return address;
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET { GENERATED or sequence options }
+ *
+ * Return the address of the affected column.
+ */
 static ObjectAddress
 ATExecSetIdentity(Relation rel, const char *colName, Node *def, LOCKMODE lockmode)
 {
@@ -5992,6 +5997,8 @@ ATExecSetIdentity(Relation rel, const char *colName, Node *def, LOCKMODE lockmod
                ObjectAddressSubSet(address, RelationRelationId,
                                                        RelationGetRelid(rel), attnum);
        }
+       else
+               address = InvalidObjectAddress;
 
        heap_freetuple(tuple);
        heap_close(attrelation, RowExclusiveLock);
@@ -5999,6 +6006,11 @@ ATExecSetIdentity(Relation rel, const char *colName, Node *def, LOCKMODE lockmod
        return address;
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN DROP IDENTITY
+ *
+ * Return the address of the affected column.
+ */
 static ObjectAddress
 ATExecDropIdentity(Relation rel, const char *colName, bool missing_ok, LOCKMODE lockmode)
 {