1 files changed, 8 insertions, 1 deletions
diff --git a/mysql-test/suite/sys_vars/t/slave_parallel_threads_basic.test b/mysql-test/suite/sys_vars/t/slave_parallel_threads_basic.test
index 8e987489d86..b567b7f8854 100644
--- a/mysql-test/suite/sys_vars/t/slave_parallel_threads_basic.test
+++ b/mysql-test/suite/sys_vars/t/slave_parallel_threads_basic.test
@@ -2,13 +2,20 @@
 
 SET @save_slave_parallel_threads= @@GLOBAL.slave_parallel_threads;
 
-SELECT @@GLOBAL.slave_parallel_threads as 'must be zero because of default';
+# Check that we don't spawn worker threads at server startup, when no
+# slave is configured (MDEV-5289).
+SELECT IF(COUNT(*) < 20, "OK", CONCAT("Found too many system user processes: ", COUNT(*))) FROM information_schema.processlist WHERE user = "system user";
+
+SELECT @@GLOBAL.slave_parallel_threads as 'must be 20 because of .cnf';
 --error ER_INCORRECT_GLOBAL_LOCAL_VAR
 SELECT @@SESSION.slave_parallel_threads  as 'no session var';
 
 SET GLOBAL slave_parallel_threads= 0;
 SET GLOBAL slave_parallel_threads= DEFAULT;
+SELECT @@GLOBAL.slave_parallel_threads as 'must be 0 because of default';
 SET GLOBAL slave_parallel_threads= 10;
 SELECT @@GLOBAL.slave_parallel_threads;
+# Check that we don't spawn worker threads when no slave is started.
+SELECT IF(COUNT(*) < 10, "OK", CONCAT("Found too many system user processes: ", COUNT(*))) FROM information_schema.processlist WHERE user = "system user";
 
 SET GLOBAL slave_parallel_threads = @save_slave_parallel_threads;