CanJBossTellMeWhenIDontCloseAConnection

最新推荐文章于 2014-01-01 11:25:19 发布

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#JBoss #Java #XML #Oracle #JSP

本文介绍了如何在JBoss中配置连接、语句和结果集的监控，确保在使用预编译语句缓存和避免数据库游标泄露时正确关闭连接、语句和结果集。此外，还提供了在生产环境和压力测试时禁用这些监控的方法。

转载自: [url]http://community.jboss.org/wiki/CanJBossTellMeWhenIDontCloseAConnection[/url]

[color=red]Can JBoss AS tell me when I don't close connections, statements or resultsets?[/color]
Yes.
[b]Connections[/b]

For connections the configuration is in deploy/transaction-service.xml

<attribute name="Debug">true</attribute>

Starting with 4.0.0, the configuration is in deploy/jbossjca-service.xml

<!-- 
     | The CachedConnectionManager is used partly to relay started UserTransactions to 
     | open connections so they may be enrolled in the new tx.
   -->
  <mbean code="org.jboss.resource.connectionmanager.CachedConnectionManager" 
         name="jboss.jca:service=CachedConnectionManager">
    <depends optional-attribute-name="TransactionManagerServiceName">jboss:service=TransactionManager</depends>

    <!-- Enable connection close debug monitoring -->
    <attribute name="Debug">true</attribute>

  </mbean>

[b]Statements and ResultSets[/b]

For statements (and from 3.2.4 ResultSets) you can add the following to your -ds.xml (data source xml: oracle-ds.xml, and so on)

 <track-statements>true</track-statements>

Like this:


    <!--pooling parameters-->
    <min-pool-size>10</min-pool-size>
    <max-pool-size>20</max-pool-size>

    <blocking-timeout-millis>60000</blocking-timeout-millis>
    <idle-timeout-minutes>180</idle-timeout-minutes>
    <track-statements>true</track-statements>

Closing statements and ResultSets is important if you want to use prepared statement caching and/or don't won't to leak cursors in your database.

[b]Servlets and JSP[/b]

From from 3.2.4 this checking is available in the web layer.
Enable the CachedConnectionValve by uncommenting the following in deploy/jbossweb-xxx.sar/server.xml:

<!-- Check for unclosed connections -->
        <Valve className="org.jboss.web.tomcat.tc5.jca.CachedConnectionValve"
            cachedConnectionManagerObjectName="jboss.jca:service=CachedConnectionManager" ></Valve>

NOTE: From 4.0.0 the CachedConnectionValve should be configured this way:

<Valve className="org.jboss.web.tomcat.tc5.jca.CachedConnectionValve"
            cachedConnectionManagerObjectName="jboss.jca:service=CachedConnectionManager"
            transactionManagerObjectName="jboss:service=TransactionManager" ></Valve>

JBoss 4.0.0 distribution still had the previous configuration that woulld cause a NullPointerException in CachedConnectionValve.checkTransactionComplete(CachedConnectionValve.java:198).
Once the valve is enabled, the CachedConnectionManager must be registered in deploy/jbossweb-xxx.sar/META-INF/jboss-service.xml.

At the end of the file, uncomment:

<depends>jboss.jca:service=CachedConnectionManager</depends>

[b]Production and Stress Testing[/b]
In production you will want to turn these off. You should have found all your leaks during development.