Crash when reconnecting to MySQL (3.0M3)

From: Alexander Lamb (alexander.lam..odanotech.ch)
Date: Wed Mar 26 2008 - 04:44:42 EDT

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    Hello List,

    We have an application, deployed successfully with Tapestry 5.0.11 and
    Cayenne 3.0M3 on Tomcat 6 with MySQL 5.0.

    Everything is fine until the point where a long period of inactivity
    has passed and (we suppose) all the DataContexts are garbage collected
    (we create one DataContext per user session).
    The first user who logs in will generate an error on (again, what we
    suppose) is a problem reconnecting to MySQL.

    To avoid the problem, we "ping" the app to keep it alive... We also
    tried to catch the Exception but doing so simply pushes the problem to
    another part of the program. The funny thing is that it is not the
    first attempt to connect to the database but maybe the first attempt
    using either a stored query in the model or raw SQL.

    Here is the kind of message we get:

            Communications link failure due to underlying exception:

    ** BEGIN NESTED EXCEPTION **

    java.io.EOFException

    STACKTRACE:

    java.io.EOFException
            at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1905)
            at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2351)
            at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2862)
            at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1571)
            at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1666)
            at com.mysql.jdbc.Connection.execSQL(Connection.java:2988)
            at com.mysql.jdbc.Connection.setAutoCommit(Connection.java:4913)
            at
    org
    .apache
    .cayenne
    .conn.PooledConnectionImpl.getConnection(PooledConnectionImpl.java:129)
            at
    org.apache.cayenne.conn.PoolManager.uncheckConnection(PoolManager.java:
    383)
            at org.apache.cayenne.conn.PoolManager.getConnection(PoolManager.java:
    367)
            at org.apache.cayenne.conn.PoolManager.getConnection(PoolManager.java:
    344)
            at org.apache.cayenne.access.DataNode
    $TransactionDataSource.getConnection(DataNode.java:321)
            at org.apache.cayenne.access.DataNode.performQueries(DataNode.java:209)
            at
    org
    .apache
    .cayenne
    .access.DataDomainQueryAction.runQuery(DataDomainQueryAction.java:442)
            at org.apache.cayenne.access.DataDomainQueryAction.access
    $000(DataDomainQueryAction.java:67)
            at org.apache.cayenne.access.DataDomainQueryAction
    $2.transform(DataDomainQueryAction.java:415)
            at
    org.apache.cayenne.access.DataDomain.runInTransaction(DataDomain.java:
    847)
            at
    org
    .apache
    .cayenne
    .access
    .DataDomainQueryAction
    .runQueryInTransaction(DataDomainQueryAction.java:412)
            at
    org
    .apache
    .cayenne
    .access.DataDomainQueryAction.execute(DataDomainQueryAction.java:119)
            at org.apache.cayenne.access.DataDomain.onQuery(DataDomain.java:740)
            at
    org
    .apache
    .cayenne
    .util.ObjectContextQueryAction.runQuery(ObjectContextQueryAction.java:
    296)
            at org.apache.cayenne.util.ObjectContextQueryAction
    $1.createObject(ObjectContextQueryAction.java:286)
            at org.apache.cayenne.cache.MapQueryCache.get(MapQueryCache.java:74)
            at
    org
    .apache
    .cayenne
    .util
    .ObjectContextQueryAction
    .interceptLocalCache(ObjectContextQueryAction.java:258)
            at
    org
    .apache
    .cayenne
    .util.ObjectContextQueryAction.execute(ObjectContextQueryAction.java:82)
            at org.apache.cayenne.access.DataContext.onQuery(DataContext.java:1331)
            at
    org.apache.cayenne.access.DataContext.performQuery(DataContext.java:
    1320)
            at
    ch
    .rodano
    .studies
    .services
    .StudySession
    .getRunningTotalPatientsByMonthForRegistryCenters(StudySession.java:466)

    etc...

    Thanks for any idea!

    Alex 

    --
Alexander Lamb
Founding Associate
RODANOTECH Sàrl

    4 ch. de la Tour de Champel
1206 Geneva
Switzerland

    Tel:  022 347 77 37
Fax: 022 347 77 38

    http://www.rodanotech.ch

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