Hello Hibernate and c3p0 users

I searched everywhere and only found one non-definitive
link about the following debug output:

02:49:21,102 DEBUG NewPooledConnection:566 - com.mchange.v2.c3p0.impl.NewPooledConnection@9c5167 closed by a client.
java.lang.Exception: DEBUG -- CLOSE BY CLIENT STACK TRACE
at com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:566)
at com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:234)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.destroyResource(C3P0PooledConnectionPool.java:470)
at com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask.run(BasicResourcePool.java:964)
at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

I am using Hibenate 3.2 and c3p0-0.9.1.2

THE QUESTION: Is this significant or can this be ignored ?
(i.e.: is connection pooling working properly ?)

Thanks
Maurice Yarrow


Note:
Am using a basic c3p0 config in hibernate.cfg.xml:
<property name="c3p0.acquire_increment">1</property>
<property name="c3p0.min_size">5</property>
<property name="c3p0.max_size">20</property>
<property name="c3p0.timeout">300</property>
<property name="c3p0.max_statements">50</property>
<property name="c3p0.idle_test_period">3000</property>

<property name="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property>

Looks serious - your DB pooling code (not Hibernate) seems to be giving out a pooled connection to some module which is closing it inappropriately. I assume that eventually this connection will again be given out from the pool and cause errors because it it closed, unless the pooling libraries are smart enough to straighten it out for you.

I use a plain-vanilla Spring-MVC application, with OpenSessionInView, using c3p0 as a connection pool, and get the mentioned error every few lines of my log.



If this "error" is so important, why does c3p0 log it with DEBUG priority?

Hello:

The error is not important, it seems that is a remaining error code that means nothing. You can check this out here:


http://stackoverflow.com/questions/8403227/weird-error-close-by-client-stack-trace

However, I removed this error when I deleted the destroy-method="close" I have in the declaration of the bean.

It seems that this method can't be called by other objects, so if you declare an explicit call in other part of your application, probably the error will appear.