Grails和MySQL连接异常

Question

我有一个正在生产的grails应用程序。 今天早上，我被告知服务器无法解析的事实。 Tomcat在旋转。 我进行了研究，发现它与MySQL有关，导致闲置8个小时后连接超时。 我发现了关于有类似问题的人的stackoverflow的示例 。 但是，所有这些人都提到，如果他们再次命中服务器并刷新了连接。 对我来说，该站点完全关闭了，Tomcat无法响应。 听起来这里还有其他作用吗？

Tomcat日志中的最后一个异常

2011-Aug-30 23:58:43,283 [TP-Processor19] org.hibernate.util.JDBCExceptionReporter
 ERROR The last packet successfully received from the server was 37,118,147 milliseconds ago.  The last packet sent successfully to the server was 37,122,138 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.
2011-Aug-30 23:58:43,290 [TP-Processor19] org.codehaus.groovy.grails.web.errors.GrailsExceptionResolver
 ERROR Exception occurred when processing request: [GET] /picks/ncaafb
Stacktrace follows:
java.net.SocketException: Connection timed out
        at java.net.SocketOutputStream.socketWrite0(Native Method)
        at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
        at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
        at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
        at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
        at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3302)
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1940)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2113)
        at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2568)
        at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2113)
        at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2275)
  at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2275)
        at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96)
        at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96)
        at sportsdb.Season.getCurrentNCAAFootballSeason(Season.groovy:93)
        at PicksController$_closure2.doCall(PicksController.groovy:60)
        at PicksController$_closure2.doCall(PicksController.groovy)
        at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:190)
        at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:291)
        at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:774)
        at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:703)
        at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:896)
        at java.lang.Thread.run(Thread.java:662)
2011-Aug-30 23:58:43,315 [TP-Processor19] org.hibernate.util.JDBCExceptionReporter
 ERROR Already closed.
2011-Aug-30 23:58:43,315 [TP-Processor19] org.hibernate.util.JDBCExceptionReporter
 ERROR Already closed.
2011-Aug-30 23:58:43,316 [TP-Processor19] org.codehaus.groovy.grails.web.servlet.GrailsDispatcherServlet
 ERROR HandlerInterceptor.afterCompletion threw exception
org.hibernate.exception.GenericJDBCException: Cannot release connection
        at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:190)
        at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:291)
        at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:774)
        at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:703)
        at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:896)
        at java.lang.Thread.run(Thread.java:662)
Caused by: java.sql.SQLException: Already closed.
        at org.apache.commons.dbcp.PoolableConnection.close(PoolableConnection.java:114)
        at org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.close(PoolingDataSource.java:191)
        at $Proxy7.close(Unknown Source)
        ... 6 more

我的计划是实施上面链接中提到的解决方案，但是我想确保没有其他明显的问题在进行，因为我们得到的结果有些不同（它们的连接令人耳目一新，而我的却没有）。

Answer 1

如果使用的是Tomcat JNDI数据源，请查看一些可以在数据源上设置的参数 ，例如testOnBorrow。 如果验证失败，连接将从池中删除。 测试连接会带来一些性能开销，但是它应该可以解决此类问题。 如果您将minIdle / maxIdle设置得很高，则可以解释为什么您在重新连接时仍然遇到此问题，从而为其他人解决了该问题。