Fix flaky global_cancel.sql test (#7316)

src/test/regress/expected/global_cancel.out

@@ -9,9 +9,14 @@ SELECT 1 FROM master_add_node('localhost', :master_port, groupid => 0);
 RESET client_min_messages;
 -- Kill maintenance daemon so it gets restarted and gets a gpid containing our
 -- nodeid
-SELECT pg_terminate_backend(pid)
+SELECT COUNT(pg_terminate_backend(pid)) >= 0
 FROM pg_stat_activity
-WHERE application_name = 'Citus Maintenance Daemon' \gset
+WHERE application_name = 'Citus Maintenance Daemon';
+ ?column?
+---------------------------------------------------------------------
+ t
+(1 row)
+
 -- reconnect to make sure we get a session with the gpid containing our nodeid
 \c - - - -
 CREATE SCHEMA global_cancel;
@@ -77,6 +82,7 @@ ERROR:  must be a superuser to terminate superuser process
 SELECT pg_cancel_backend(citus_backend_gpid());
 ERROR:  canceling statement due to user request
 \c - postgres - :master_port
+DROP USER global_cancel_user;
 SET client_min_messages TO DEBUG;
 -- 10000000000 is the node id multiplier for global pid
 SELECT pg_cancel_backend(10000000000 * citus_coordinator_nodeid() + 0);

src/test/regress/sql/global_cancel.sql

@@ -5,9 +5,9 @@ RESET client_min_messages;
 
 -- Kill maintenance daemon so it gets restarted and gets a gpid containing our
 -- nodeid
-SELECT pg_terminate_backend(pid)
+SELECT COUNT(pg_terminate_backend(pid)) >= 0
 FROM pg_stat_activity
-WHERE application_name = 'Citus Maintenance Daemon' \gset
+WHERE application_name = 'Citus Maintenance Daemon';
 
 -- reconnect to make sure we get a session with the gpid containing our nodeid
 \c - - - -
@@ -58,6 +58,8 @@ SELECT pg_cancel_backend(citus_backend_gpid());
 
 \c - postgres - :master_port
 
+DROP USER global_cancel_user;
+
 SET client_min_messages TO DEBUG;
 
 -- 10000000000 is the node id multiplier for global pid