Fix failure_single_select

src/test/regress/expected/failure_single_select.out

@@ -144,6 +144,7 @@ INSERT INTO select_test VALUES (3, 'even more data');
 SELECT * FROM select_test WHERE key = 3;
 ERROR:  connection to the remote node postgres@localhost:xxxxx failed with the following error: connection not open
 COMMIT;
+-- Maintenance connections are not cached
 SELECT citus.mitmproxy('conn.onQuery(query="SELECT.*pg_prepared_xacts").after(2).kill()');
  mitmproxy
 ---------------------------------------------------------------------
@@ -157,8 +158,11 @@ SELECT recover_prepared_transactions();
 (1 row)
 
 SELECT recover_prepared_transactions();
-ERROR:  connection not open
-CONTEXT:  while executing command on localhost:xxxxx
+ recover_prepared_transactions
+---------------------------------------------------------------------
+                             0
+(1 row)
+
 -- bug from https://github.com/citusdata/citus/issues/1926
 SET citus.max_cached_conns_per_worker TO 0; -- purge cache
 DROP TABLE select_test;

src/test/regress/sql/failure_single_select.sql

@@ -77,6 +77,7 @@ INSERT INTO select_test VALUES (3, 'even more data');
 SELECT * FROM select_test WHERE key = 3;
 COMMIT;
 
+-- Maintenance connections are not cached
 SELECT citus.mitmproxy('conn.onQuery(query="SELECT.*pg_prepared_xacts").after(2).kill()');
 SELECT recover_prepared_transactions();
 SELECT recover_prepared_transactions();