我承认我在DZ上有RPWT
操作cdb_sessions表，发现大量的locked，直接后果就是mysql无法响应WEB的请求，WEB无法响应浏览器端的请求。
太壮观：
+-------+------+-----------+--------+---------+------+--------+------------------------------------------------------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+-------+------+-----------+--------+---------+------+--------+------------------------------------------------------------------------------------------------------+
| 84082 | root | localhost | discuz | Query | 54 | update | INSERT INTO cdb_sessions (sid, ip1, ip2, ip3, ip4, uid, username, groupid, styleid, invisible, acti |
| 84083 | root | localhost | discuz | Query | 54 | Locked | DELETE FROM cdb_sessions WHERE sid='Z71z19' OR lastactivity<(1245657270-900) OR ('0'<>'0' AND uid=' |
| 84084 | root | localhost | discuz | Query | 54 | Locked | SELECT uid, username, groupid, invisible, action, lastactivity, fid FROM cdb_sessions WHERE uid <> 0 |
| 84086 | root | localhost | discuz | Query | 54 | Locked | SELECT uid, username, groupid, invisible, action, lastactivity, fid FROM cdb_sessions WHERE uid <> 0 |
| 84085 | root | localhost | discuz | Query | 54 | Locked | SELECT uid, username, groupid, invisible, action, lastactivity, fid FROM cdb_sessions WHERE uid <> 0 |
| 84087 | root | localhost | discuz | Query | 54 | Locked | SELECT uid, username, groupid, invisible, action, lastactivity, fid FROM cdb_sessions WHERE uid <> 0 |
| 84088 | root | localhost | discuz | Query | 54 | Locked | SELECT uid, username, groupid, invisible, action, lastactivity, fid FROM cdb_sessions WHERE uid <> 0 |
| 84089 | root | localhost | discuz | Query | 54 | Locked | SELECT uid, username, groupid, invisible, action, lastactivity, fid FROM cdb_sessions WHERE uid <> 0 |
| 84090 | root | localhost | discuz | Query | 54 | Locked | SELECT uid, username, groupid, invisible, action, lastactivity, fid FROM cdb_sessions WHERE uid <> 0 |
| 84091 | root | localhost | discuz | Query | 54 | Locked | SELECT uid, username, groupid, invisible, action, lastactivity, fid FROM cdb_sessions WHERE uid <> 0 |
| 84092 | root | localhost | discuz | Query | 54 | Locked | SELECT uid, username, groupid, invisible, action, lastactivity, fid FROM cdb_sessions WHERE uid <> 0 |
| 84093 | root | localhost | discuz | Query | 54 | Locked | DELETE FROM cdb_sessions WHERE sid='wsX92s' OR lastactivity<(1245657270-900) OR ('0'<>'0' AND uid=' |
| 84095 | root | localhost | discuz | Query | 54 | Locked | SELECT uid, username, groupid, invisible, action, lastactivity, fid FROM cdb_sessions WHERE uid <> 0 |
| 84096 | root | localhost | discuz | Query | 54 | Locked | DELETE FROM cdb_sessions WHERE sid='Ra5ZqL' OR lastactivity<(1245657270-900) OR ('0'<>'0' AND uid=' |
| 84094 | root | localhost | discuz | Query | 54 | Locked | SELECT uid, username, groupid, invisible, action, lastactivity, fid FROM cdb_sessions WHERE uid <> 0 |
| 84097 | root | localhost | discuz | Query | 54 | Locked | SELECT sid, uid AS sessionuid, groupid, groupid='6' AS ipbanned, pageviews AS spageviews, styleid, l |
| 84100 | root | localhost | discuz | Query | 54 | Locked | SELECT sid, uid AS sessionuid, groupid, groupid='6' AS ipbanned, pageviews AS spageviews, styleid, l |
| 84099 | root | localhost | discuz | Query | 54 | Locked | SELECT uid, username, groupid, invisible, action, lastactivity, fid FROM cdb_sessions WHERE uid <> 0 |
最为BT的是，这些locked形成之后，必须重启mysql才行
转载时务必以超链接形式标明文章原始出处和作者信息。
真汗，忘记填写Email提交后退内容全没了：（
重新写。
cdb_seesions表是MEMORY类型，是内存操作，一般不会出现这么恐怖的锁表情况的，我见过很多15分钟在线过K的也没什么问题的。
建议检查一下cdb_sessions表是否有问题，是否类型不是MEMORY了。删除这个表重新建立一个吧。
另外，看看在线保持时间是否设置太小了？这个值设置小的话相对统计在线比较精确但也会造成频繁的update操作。一般K级的在线，15分钟就可以了。
还有就是，你是否使用的是远程链接数据库？如果是的话，尝试使用ip进行连接，关闭mysql的反向解析。
最后，尝试更改连接数据库的方式，如果是持久链接改成非持久连接。
希望能对你有帮助。