Wed, 15 Sep 2010 09:57:00 GMT

Throwable occurred: org.springframework.transaction.CannotCreateTransactionException: Could not open JDBC Connection for transaction; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was 50,123,505 milliseconds ago. The last packet sent successfully to the server was 50,123,505 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.

�q�主要是�׃��个原因引��h��?
1.mysql �?x��)自动关闭长旉��不用的connection,一个连接如果处于sleep状态达到mysql的参数wait_timeout指定的时�?默认�?��时),��是自动关闭�q�个�q�接
2.common pool中没有指定相应的�q�接��(g��)查参�?br />

解决办法:从common pool的配�|�参数来解决:

   ${db.driver}


   ${db.url}


   ${db.user}


   ${db.password}


   100


   50


   10000

   3600000




   true


   select 1 from dual

使用上述的三个红色的参数,��可以避免这个问�?�q�三个参数的意义:

timeBetweenEvictionRunsMillis:启动connection校验定时�?定时器运行时间间隔就是timeBetweenEvictionRunsMillis的�?默认�?1,表示不启动定时器,�q�里讑֮��?��时,只要��于mysql的wait_timeout��可以了(ji��n)

testWhileIdle: true,表示��(g��)查idle的connection,false��Z��(g��)�?br />
validationQuery:用于��(g��)查connection的sql语句.

�q�只是一�U�方�?另外的几�U�方�?

timeBetweenEvictionRunsMillis+minEvictableIdleTimeMillis:�q�种方式不检查Connection的有效�?而是��(g��)查连接的�I�闲旉��,大于minEvictableIdleTimeMillis��清�?


   3600000



   120000


如果不喜�Ƣ用定时�?也可以配�|�testOnBorrow+validationQuery参数:每次从连接池取参数都�?x��)校验连接的有效�?实际上这�U�方式性能�?x��)比定时器差�?

   true


   select 1 from dual


另外,也可以用testOnReturn+validationQuery,不过未必�?x��)解决问�?�q�表�C�每�ơ��用完�q�接,归还�q�接池的时候检查连接的有效�?�q�有可能��D��使用一�ơ无效的�q�接,最好不要用.

上面的几�U�方法可以合�q��?只是��(g��)查的点多�?未必是好�?br />

另外,也可以��用Abandoned的那几个参数,来删除连接池中的�q�接.也能辑ֈ�效果.我没��试.

王卫�?/a> 2010-09-15 17:57 发表评论

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