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 0653194c78d8e9b25e292806dbe821cb1e00cff8..3dc1e38ada0a1f67af7895c53004d67a93afcbec 100644 (file)
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -508,9 +508,13 @@ 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);
        }