I have a grails application that is in production now. This morning I was alerted to the fact that the server was not resolving. Tomcat was spinning and spinning. I researched and it looks like it has to do with MySQL causing the connection to timeout after 8 hours of inactivity. I have found examples on stackoverflow of people having similar problems. However, all of these people mention that if they hit the server again and the connection is refreshed. For me, the site was down entirely and Tomcat wouldn't respond. Does it sound like something else could be at play here?
Last Exception in Tomcat log
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)
开发者_开发百科 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
My plan is to implement the solution mentioned in the link above, but I wanted to make sure nothing else visibly fishy was going on since we have a somewhat different result (their connections are refreshing and mine are not).
If you're using a Tomcat JNDI DataSource look at some of the parameters you can set on the datasource such as testOnBorrow. If validation fails the connection will be dropped from the pool. There is some performance overhead that you will incur by testing connections, but it should fix problems like this. If you have minIdle/maxIdle set high that would explain why you continue to experience the problem while reconnecting fixes it for other people.
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