1. 慢查询日志的作用 慢查询日志默认不开启,建议手动开启,方便我们定位线上问题. 执行时间超过阈值的SQL会被写入到慢查询日志当中,这样可以帮助我们记录执行时间过长的SQL语句,定位线上慢SQL问题,方便我们进行SQL性能调优. 2. 慢查询日志的配置 2.1 查看是否开启了慢查询日志 show variables like 'slow_query_log'; 默认是OFF,不开启,可以手动开启. 2.2 开启慢查询日志 一种方法是可以使用MySQL命令开启: set global slow_
Description Tom is a commander, his task is destroying his enemy’s transportation system. Let’s represent his enemy’s transportation system as a simple directed graph G with n nodes and m edges. Each node is a city and each directed edge is a directe