people were suffering from this exception in hibernate forums, it was
suggested to switch from DBCP to c3po.
Note also that the config you provided is not using any pooling at all.
Datasources are not pooled by default.
On Sat, Jun 21, 2008 at 8:18 AM, Thomas Haines <
[EMAIL PROTECTED]> wrote:
> Hello
>
> I am experiencing a reproducible problem with connection pooling in Tomcat,
> although I suspect it is not a Tomcat issue per se.
>
> I am running:
> mysql server 5.0.58
> tomcat 6.0.16
> mysql connector 5.1.6
> java version 1.5.0_13
> all on CentOS 5
>
> The following error occurs when there has been no activity between the DB
> and Tomcat for some period of time:
>
> ERROR (21-06-08 07:59) [servlets.ViewEmail]
> com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet
> successfully received from the server was 46859 seconds ago.The last packet
> sent successfully to the server was 46859 seconds ago, which 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.
> at sun.reflect.GeneratedConstructorAccessor17.newInstance(Unknown
> Source)
> at
> sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
> at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
> at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
> at
> com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
> at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3246)
> at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1917)
> at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2060)
> at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2542)
> at
> com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1734)
> at
> com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1885)
> at
> org.apache.tomcat.dbcp.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:93)
> at
> com.ghf.util.MailoutUtils.getRecipientbyChecksum(MailoutUtils.java:123)
> INFO (21-06-08 08:01) [servlets.ViewEmail] : View email request
> successfully processed
> INFO (21-06-08 08:02) [servlets.ViewEmail] : View email request
> successfully processed
>
>
> At this juncture, I am unsure how to remedy this. My only two thoughts are
> to either:
>
> a) downgrade to MySQL Connector/J 5.0.8 and see if this fixes it;
> b) add a while (!verified && attempts<2) type loop in getConnection()
> method to query the DB using a minimal query and then catch the first dead
> connection.
>
> I'm not overly keen on introducing the additional overhead of querying the
> DB just to check if it is valid every time a request is made for a
> connection. Does anyone have any thoughts on how I might debug/solve this
> issue? I've searched widely on Google to no avail. Interestingly, there is
> another instance of tomcat communicating with MySQL on the machine, exactly
> the same configuration, that doesn't suffer these woes. Any help would be
> appreciated!
>
> Tom
>
> Other relevant snippets:
> META-INF/context.xml:
> <?xml version="1.0" encoding="UTF-8"?>
> <Context path="/dyn">
> <Resource name="jdbc/ghip" auth="Container"
> type="javax.sql.DataSource"
> maxActive="50"
> maxIdle="5"
> maxWait="10000"
> username="******"
> password="******"
> driverClassName="com.mysql.jdbc.Driver"
> removeAbandoned="true"
> removeAbandonedTimeout="180"
> url="jdbc:mysql://localhost:3306/ghip?autoReconnect=true"
> />
> </Context>
>
>
> DBPool.java exert:
> /**
> * Method getConnection.
> * @return Connection New connection from the pool
> */
> public static Connection getConnection() {
>
> Connection conn = null;
>
> try {
> Context ctx = (Context) new
> InitialContext().lookup("java:comp/env");
> conn = ((DataSource)
> ctx.lookup("jdbc/ghip")).getConnection();
> }
> catch (Exception e) {
> e.printStackTrace(System.err);
> }
>
> return conn;
> }
>
>
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>
--
Regards, Youssef
