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Date: Wed, 8 May 2013 09:20:22 -0300
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Subject: Tomcat thread dump analysis
From: Charles Richard <charles.r@thelearningbar.com>
To: Tomcat Users List <users@tomcat.apache.org>
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Hi,

We have a weird issue on our site which some random trigger event will
backup all c3p0 connections until it hits the max pool size.

I have scripts that will do a softReset on the c3p0 connection pool when
they hit their max so help us manage the issue and to also help me have
time to hopefully get some decent thread dumps to catch the underlying
issue.

The problem happened yesterday and I get a lot of these:

"TP-Processor396" daemon prio=10 tid=0x00002aff2ba9d000 nid=0x5a7b waiting
on condition [0x00002aff61e98000]
   java.lang.Thread.State: WAITING (parking)
        at sun.misc.Unsafe.park(Native Method)
        - parking to wait for  <0x00002afecfb91da0> (a
java.util.concurrent.Semaphore$NonfairSync)
        at java.util.concurrent.locks.LockSupport.park(LockSupport.java:158)
        at
java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:811)
        at
java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:969)
        at
java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1281)
        at java.util.concurrent.Semaphore.acquire(Semaphore.java:286)
        at
com.tc.object.locks.LockStateNode$PendingLockHold.park(LockStateNode.java:179)
        at
com.tc.object.locks.ClientLockImpl.acquireQueued(ClientLockImpl.java:723)
        at
com.tc.object.locks.ClientLockImpl.acquireQueued(ClientLockImpl.java:701)
        at com.tc.object.locks.ClientLockImpl.lock(ClientLockImpl.java:52)
        at
com.tc.object.locks.ClientLockManagerImpl.lock(ClientLockManagerImpl.java:98)
        at com.tc.object.bytecode.ManagerImpl.lock(ManagerImpl.java:747)

If I look at a stack before the issue happened, I see no TP-Processor
threads with the "parking to wait for". What can i read into this?

Thanks,
Charles

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