diff --git a/contrib/test_decoding/specs/subxact_logged_without_top.spec b/contrib/test_decoding/specs/subxact_logged_without_top.spec
new file mode 100644
index 0000000000..55b51357a9
--- /dev/null
+++ b/contrib/test_decoding/specs/subxact_logged_without_top.spec
@@ -0,0 +1,51 @@
+
+setup
+{
+    SELECT 'init' FROM pg_create_logical_replication_slot('isolation_slot', 'test_decoding'); -- must be first write in xact
+    CREATE TABLE harvest(apples integer);
+    CREATE OR REPLACE FUNCTION subxacts() returns void as $$
+    BEGIN
+      FOR i in 1 .. 65 LOOP
+        BEGIN
+          INSERT INTO harvest VALUES (42);
+        EXCEPTION
+        WHEN OTHERS THEN
+	  RAISE;
+        END;
+    END LOOP;
+    END; $$LANGUAGE 'plpgsql';
+}
+
+teardown
+{
+    DROP TABLE IF EXISTS harvest;
+    SELECT 'stop' FROM pg_drop_replication_slot('isolation_slot');
+}
+
+session "s0"
+setup { SET synchronous_commit=on; }
+step "s0_begin" { BEGIN; }
+step "s0_first_subxact" {
+    DO LANGUAGE plpgsql $$
+      BEGIN
+        BEGIN
+          INSERT INTO harvest VALUES (41);
+	EXCEPTION WHEN OTHERS THEN RAISE;
+	END;
+      END $$;
+}
+step "s0_many_subxacts" { select subxacts(); }
+step "s0_commit" { COMMIT; }
+
+session "s1"
+setup { SET synchronous_commit=on; }
+step "s1_begin" { BEGIN; }
+step "s1_dml" { INSERT INTO harvest VALUES (43); }
+step "s1_commit" { COMMIT; }
+
+session "s2"
+setup { SET synchronous_commit=on; }
+step "s2_checkpoint" { CHECKPOINT; }
+step "s2_get_changes" { SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1'); }
+
+permutation "s0_begin" "s0_first_subxact" "s2_checkpoint" "s1_begin" "s1_dml" "s0_many_subxacts" "s0_commit" "s2_checkpoint" "s2_get_changes" "s1_commit" "s2_get_changes"