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javaspringjmxc3p0

How to get fixed object name for c3p0 mbeans object

I am using pooledDataSources in my application. ObjectName of Mbean for PooledDataSource contain variable part along with it. for example:

ObjectName = com.mchange.v2.c3p0:type=PooledDataSource[z8kfsx9c4bily2r1i962|23696a1b]

has variable as z8kfsx9c4bily2r1i962|23696a1b and it changes everytime i restart my service. I have to get fixed ObjectName for my mbean for monitoring purpose. I am using jmx for monitoring. I tried to override vmid property but it seems its a not writable property. Did a lot of research on this but running out of luck.

My Jmx Configuration is as following:

<jmxtrans-agent> <queries> <!-- C3P0 --> <query objectName="com.mchange.v2.c3p0:type=PooledDataSource" attribute="threadPoolNumTasksPending" resultAlias="cp.threadPoolNumTasksPending"/> </queries> </jmxtrans-agent>

Thanks in advance

Solution

  • By default, c3p0 JMX names look like this:

    com.mchange.v2.c3p0:type=PooledDataSource,identityToken=<variable, opaque token>

    In order to get a constant identifier, you must set ensure that the property dataSourceName is set. The best way to do that is to give your DataSource a name upon construction:

    ComboPooledDataSource cpds = new ComboPooledDataSource("Jojo")

    But you can also set dataSourceName like any other c3p0 config property.

    Then you'll have JMX names that look like:

    com.mchange.v2.c3p0:type=PooledDataSource,identityToken=<variable, opaque token>,name=Jojo

    Many JMX clients let you search on attributes, so this is sufficient to give yourself a permanent monitor.

    If you really need a constant, fixed, JMX name, you can set the property

    com.mchange.v2.c3p0.management.ExcludeIdentityToken=true

    This can go in a c3p0.properties file, as a System property, or as a HOCON/typesafe config path, depending how you are configuring c3p0. If you set this property and also set dataSourceName (again, via a constructor or in your config), then your JMX name will be a predictable, fixed String, like

    com.mchange.v2.c3p0:type=PooledDataSource,name=Jojo

    It will be up to you to ensure these names are unique.

    Note: com.mchange.v2.c3p0.management.ExcludeIdentityToken=true is a new-ish feature, please be sure you are using the latest c3p0-0.9.5.1

    For more details, see c3p0's JMX configuration docs.