Session 1: mysql> start transaction; Query OK, 0 rows affected (0.00 sec) mysql> update ClientActionTrack20151125 set ip='8.8.8.8'; Session 2: mysql> update ClientActionTrack20151125 set ip='9.9.9.9' -> ; ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transactio zabbix:/root/mysql# sh ./mon_mysql_all.sh ,,,,, 112069896,555,update ClientActionTrack20151125 set ip='9.9.9.9',112069895,554,update ClientActionTrack20151125 set ip='8.8.8.8' mysql[192.168.11.187] blocking_thread[554] blocking_query[update ClientActionTrack20151125 set ip='8.8.8.8'] blocking waiting_thread[555]'s update ClientActionTrack20151125 set ip='9.9.9.9'