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 5811bcd074c54e34d485188fa7b413774e1c7f24..194a692aeb48dbfa2d382f74d3ac2b62cc1928ee 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);
        }