mysql连接hang住问题分析(二)

MYSQL_OPT_READ_TIMEOUT (argument type: unsigned int *)

The timeout in seconds for attempts to read from the server. Each attempt usesthis timeout value and there are retries if necessary, so the total effectivetimeout value is three times the option value. You can set the value so that alost connection can be detected earlier than the TCP/IP Close_Wait_Timeoutvalue of 10 minutes. Before MySQL 5.1.41, this option applies only to TCP/IPconnections and, prior to MySQL 5.1.12, only for Windows.

MYSQL_OPT_WRITE_TIMEOUT (argument type: unsigned int *)

The timeout in seconds for attempts to write to the server. Each attempt usesthis timeout value and there are net_retry_count retries if necessary, so thetotal effective timeout value is net_retry_count times the option value. BeforeMySQL 5.1.41, this option applies only to TCP/IP connections and, prior toMySQL 5.1.12, only for Windows.

然而，值得注意的是此两个参数并不是对所有版本都支持：

Before MySQL 5.1.41, this option applies only to TCP/IPconnections and, prior to MySQL 5.1.12, only for Windows.

对于linux 系统来说，你必须使用官方发布的5.1.12版本之后的客户端库，否则你需要自己编译线程安全的客户端库。