Grails和MySQL連接異常

Question

我有一個正在生產的grails應用程序。 今天早上，我被告知服務器無法解析的事實。 Tomcat在旋轉。 我進行了研究，發現它與MySQL有關，導致閑置8個小時后連接超時。 我發現了關於有類似問題的人的stackoverflow的示例 。 但是，所有這些人都提到，如果他們再次命中服務器並刷新了連接。 對我來說，該站點完全關閉了，Tomcat無法響應。 聽起來這里還有其他作用嗎？

Tomcat日志中的最后一個異常

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

我的計划是實施上面鏈接中提到的解決方案，但是我想確保沒有其他明顯的問題在進行，因為我們得到的結果有些不同（它們的連接令人耳目一新，而我的卻沒有）。

Answer 1

如果使用的是Tomcat JNDI數據源，請查看一些可以在數據源上設置的參數 ，例如testOnBorrow。 如果驗證失敗，連接將從池中刪除。 測試連接會帶來一些性能開銷，但是它應該可以解決此類問題。 如果您將minIdle / maxIdle設置得很高，則可以解釋為什么您在重新連接時仍然遇到此問題，從而為其他人解決了該問題。