MySQL日志中Communication Errors and Aborted Connec...
130504 2:14:32 [Warning] Aborted connection 13145 to db: tjss_pmanager user: xxxx host: 192.168.0.96 (Got an error writing communication packets) 130504 2:15:13 [Warning] Aborted connection 13146 to db: tjss_pmanager user: xxxx host: 192.1
130504 2:14:32 [Warning] Aborted connection 13145 to db: 'tjss_pmanager' user: 'xxxx' host: '192.168.0.96' (Got an error writing communication packets)
130504 2:15:13 [Warning] Aborted connection 13146 to db: 'tjss_pmanager' user: 'xxxx' host: '192.168.0.93' (Got an error writing communication packets)
如果你的sleep进程数在同一时间内过多，再加上其他状态的连接，总数超过了max_connection的值，那mysql除了root用户外，就无法再继续处理任何请求无法与任何请求建立连接或者直接down了。所以，这个问题在大负载的情况下还是相当严重的。如果发现你的mysql有很多死连接存在，首先要先检查你的程序是否使用的是pconnect的方式，其次，检查在页面执行完毕前是否及时调用了mysql_close()，
还有一个办法，你可以在my.cnf里面加上wait_timeout和interactive_timeout，把他们的值设的小一些，默认情况下wait_timeout的值是8小时的时间，你可以改成1个小时，或半个小时。这样mysql会更快的杀死死连接。防止连接总数超过max_connection的值。或者把max_connection的值设置的更大，不过这样显然不妥，连接的数量越多，对你服务器的压力越大。实际上那些连接都是冗余的，把它们尽快杀死才是上策。
官方网站有详细的解释: http://dev.mysql.com/doc/refman/5.1/en/communication-errors.html
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