Don't call CheckAttributeType() with InvalidOid on dropped cols

If CheckAttributeType() is called with InvalidOid, it performs a bunch
of pointless, futile syscache lookups with InvalidOid, but ultimately
tolerates it and has no effect. We were calling it with InvalidOid on
dropped columns, but it seems accidental that it works, so let's stop
doing it.

Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://www.postgresql.org/message-id/93ce56cd-02a6-4db1-8224-c8999372facc@iki.fi
Backpatch-through: 14

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index b8643efee91fd4c24520998b54d0a7e85b6d7e88..5404eee00190b44da96bfc0a2211c3980823affe 100644 (file)
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -550,9 +550,13 @@ CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind,
         */
        for (i = 0; i < natts; i++)
        {
-               CheckAttributeType(NameStr(TupleDescAttr(tupdesc, i)->attname),
-                                                  TupleDescAttr(tupdesc, i)->atttypid,
-                                                  TupleDescAttr(tupdesc, i)->attcollation,
+               Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+
+               if (attr->attisdropped)
+                       continue;
+               CheckAttributeType(NameStr(attr->attname),
+                                                  attr->atttypid,
+                                                  attr->attcollation,
                                                   NIL, /* assume we're creating a new rowtype */
                                                   flags);
        }