查詢當前正在運行的SQL語句，通過status命令，查看Slow querIEs這一項，如果值長時間>0,說明有查詢執行時間過長
以下為引用的內容：
MySQL> status;
--------------
MySQL Ver 11.18 Distrib 3.23.58, for redhat-Linux-gnu (i386)
Connection id: 53
Current database: (null)
Current user: root@localhost
Current pager: stdout
Using outfile: ’’
Server version: 5.0.37-log
Protocol version: 10
Connection: Localhost via Unix socket
ClIEnt characterset: latin1
Server characterset: latin1
Unix socket: /tmp/MySQL.sock
Uptime: 4 days 16 hours 49 min 57 sec
Threads: 1 Questions: 706 Slow querIEs: 0 Opens: 177 Flush tables: 1 Open tables:
52 QuerIEs per second avg: 0.002
--------------
這時再通過show processlist命令來查看當前正在運行的SQL，從中找出運行慢的SQL語句，找到執行慢的語句後，再用explain命令查看這些語句的執行計劃。
MySQL> show processlist;
+----+------+-----------+------+---------+------+-------+------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+-------+------------------+
| 53 | root | localhost | NULL | Query | 0 | NULL | show processlist |
+----+------+-----------+------+---------+------+-------+------------------+
