diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index a182176..a274d82 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -2375,14 +2375,18 @@ Check constraints:
 
 DROP TABLE alter2.tt8;
 DROP SCHEMA alter2;
--- Check that we map relation oids to filenodes and back correctly.
--- Only display bad mappings so the test output doesn't change all the
--- time.
+-- Check that we map relation oids to filenodes and back correctly.  Only
+-- display bad mappings so the test output doesn't change all the time.  A
+-- filenode function call can return NULL for a relation dropped concurrently
+-- with the call's surrounding query, so check mappings only for relations
+-- that still exist after all calls finish.
+CREATE TEMP TABLE filenode_mapping AS
 SELECT
     oid, mapped_oid, reltablespace, relfilenode, relname
 FROM pg_class,
     pg_filenode_relation(reltablespace, pg_relation_filenode(oid)) AS mapped_oid
 WHERE relkind IN ('r', 'i', 'S', 't', 'm') AND mapped_oid IS DISTINCT FROM oid;
+SELECT m.* FROM filenode_mapping m JOIN pg_class c ON c.oid = m.oid;
  oid | mapped_oid | reltablespace | relfilenode | relname 
 -----+------------+---------------+-------------+---------
 (0 rows)
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 3f641f9..19e1229 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -1582,15 +1582,20 @@ ALTER TABLE IF EXISTS tt8 SET SCHEMA alter2;
 DROP TABLE alter2.tt8;
 DROP SCHEMA alter2;
 
--- Check that we map relation oids to filenodes and back correctly.
--- Only display bad mappings so the test output doesn't change all the
--- time.
+-- Check that we map relation oids to filenodes and back correctly.  Only
+-- display bad mappings so the test output doesn't change all the time.  A
+-- filenode function call can return NULL for a relation dropped concurrently
+-- with the call's surrounding query, so check mappings only for relations
+-- that still exist after all calls finish.
+CREATE TEMP TABLE filenode_mapping AS
 SELECT
     oid, mapped_oid, reltablespace, relfilenode, relname
 FROM pg_class,
     pg_filenode_relation(reltablespace, pg_relation_filenode(oid)) AS mapped_oid
 WHERE relkind IN ('r', 'i', 'S', 't', 'm') AND mapped_oid IS DISTINCT FROM oid;
 
+SELECT m.* FROM filenode_mapping m JOIN pg_class c ON c.oid = m.oid;
+
 -- Checks on creating and manipulation of user defined relations in
 -- pg_catalog.
 --