1SET @save_slave_parallel_threads= @@GLOBAL.slave_parallel_threads; 2SELECT IF(COUNT(*) < 20, "OK", CONCAT("Found too many system user processes: ", COUNT(*))) FROM information_schema.processlist WHERE user = "system user"; 3IF(COUNT(*) < 20, "OK", CONCAT("Found too many system user processes: ", COUNT(*))) 4OK 5SELECT @@GLOBAL.slave_parallel_threads as 'must be 20 because of .cnf'; 6must be 20 because of .cnf 720 8SELECT @@SESSION.slave_parallel_threads as 'no session var'; 9ERROR HY000: Variable 'slave_parallel_threads' is a GLOBAL variable 10SET GLOBAL slave_parallel_threads= 0; 11SET GLOBAL slave_parallel_threads= DEFAULT; 12SELECT @@GLOBAL.slave_parallel_threads as 'must be 0 because of default'; 13must be 0 because of default 140 15SET GLOBAL slave_parallel_threads= 10; 16SELECT @@GLOBAL.slave_parallel_threads; 17@@GLOBAL.slave_parallel_threads 1810 19SELECT IF(COUNT(*) < 10, "OK", CONCAT("Found too many system user processes: ", COUNT(*))) FROM information_schema.processlist WHERE user = "system user"; 20IF(COUNT(*) < 10, "OK", CONCAT("Found too many system user processes: ", COUNT(*))) 21OK 22SET GLOBAL slave_parallel_threads = @save_slave_parallel_threads; 23