SET @global_slow_query_log = @@global.slow_query_log; SET @global_log_output = @@global.log_output; SET @@session.long_query_time=1; SET @@global.log_output = 'TABLE'; '----When slow_query_log = OFF----' SET @@global.slow_query_log = OFF; TRUNCATE mysql.slow_log; SELECT sleep(2); sleep(2) 0 SELECT count(*) FROM mysql.slow_log; count(*) 0 '----When slow_query_log = ON-----' SET @@global.slow_query_log = ON; TRUNCATE mysql.slow_log; SELECT sleep(2); sleep(2) 0 SELECT count(*) FROM mysql.slow_log; count(*) 1 SET @@global.log_output = @global_log_output; SET @global.slow_query_log = @global_slow_query_log;