使用 Yii在高并发时,发生连接mysql数据库失败，求解释
PHP Fatal error: Uncaught exception 'CDbException' with message 'CDbConnection failed to open the DB connection: SQLSTATE[HY000] [2003] Can't connect to MySQL server on '***.***.***.**' (4)' in /**/**/framework/ db/CDbConnection.php:348
错误信息如上。开发完成测试一切正常，功能但上线后，并发高峰时就会出现个别500。很是诡异。求助啊 。
------解决方案--------------------
Yii框架 CDbConnection 默认将设置 'emulatePrepare' => true ， 这样PDO-mysql连接 以长连接方式连接数据库。再高并发时有时会发生连接数 维持过多。新连接失效的问题。我猜是这样！
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