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From Louis Zipes <>
Subject RE: Application hanging on Tomcat 7.0.54
Date Wed, 26 Sep 2018 19:56:43 GMT
Problem just re-occurred and so I was able to at least get a JSTACK  (I assume it was Tomcat
since it was the Java using the most memory on the machine).  Here is the reoccurring message.
 I get more hits on but haven't dug through all of the Google hits yet (due to multi-tasking)
so apologies up front if there is a simple answer to this.

"Event_Manager_1413" daemon prio=6 tid=0x0000000024856000 nid=0x40c4 waiting on condition
   java.lang.Thread.State: TIMED_WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for  <0x00000005ab45f7b8> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.parkNanos(Unknown Source)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(Unknown
at java.util.concurrent.LinkedBlockingQueue.poll(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.getTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$ Source)
at Source)

   Locked ownable synchronizers:
- None

> Any comments/suggestions are appreciated!

Your most likely problem is database connection pool mismanagement:
connections aren't properly released and the pool empties. All threads
are left waiting on available database connections which will never be

I'm using the ojdbc6.jar if that is what you are referring to or is there a better setting

-----Original Message-----
From: Christopher Schultz []
Sent: Wednesday, September 26, 2018 3:46 PM
Subject: Re: Application hanging on Tomcat 7.0.54

- - - external message, proceed with caution - - -

Hash: SHA256


On 9/26/18 14:42, Louis Zipes wrote:
> Hi all, Tomcat 7.0.54 running on Windows 2012
> We are running a third party application on Tomcat and today we
> have intermittently run in issues where the application stops
> working.  The big changes in our system is that we have added more
> end users and we are at year end so of course everyone is hitting
> the system hard. Even if we force a log out of all users and stop
> all background jobs then the application doesn't recover.
> We see no active sessions on the database (our application is
> connecting to an Oracle database) and I see no clear error messages
> in either our third party application logs or the Tomcat logs (ex.
> OutofMemory).  When we go to the Windows Task Manager we did not
> see the machine's Memory max'd out but admittedly I didn't look at
> the Java session to see if was reaching its Heap Max.  The only
> thing that we noticed was that TCP connections went down right
> after the restart.  I did open up Jconsole under Java and I did
> force a garbage collection but that didn't seem to help.
> We do have an Oracle Grid Control and we did get an alert in
> regards to Metric: [HTTP Transaction] Perceived Time per Page going
> past thresholds but not sure if that was just an old alert with and
> old range that was set up a long time ago or is a really valid
> clue.    Since this is PRD we had to get it back up and running so
> all I did was increase the Tomcat Xmx Heap size and restarted.  I'm
> not really confident that is the solution since as mentioned you
> tend to see a clear out of memory error if it was too small.
> So a few questions:
> 1)     Does this sound like a known issue with this earlier version
> of Tomcat?


> 2)     Should I turn up any logging on Tomcat and if so which
> ones?

Not yet.

> 3)     We didn't do a JSTACK dump while it was happening.  Would
> that have been useful?


> 4)     Do we need to play around with MaxThreads and/or
> MaxConnections.  We do have maxThreads in our server.mxl but in DEV
> when we turned it down to a value = 5  hoping to overwhelm it
> nothing bad happened.

Don't change anything, yet.

> Once again, we are limited to what we could do and collect since it
> was PRD and we needed to restart it.  We restarted the Tomcat
> service and everything is processing fine for right now.  I will
> note that that we did have that bad Windows patch that prevented it
> from stopping and starting cleanly
> (
> but we have taken the break fix patch and the daily restarts seem
> to be fine since then.
> Any comments/suggestions are appreciated!

Your most likely problem is database connection pool mismanagement:
connections aren't properly released and the pool empties. All threads
are left waiting on available database connections which will never be

- -chris
Comment: Using GnuPG with Thunderbird -


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