Re: WOWorkerThread deadlocks
Re: WOWorkerThread deadlocks
- Subject: Re: WOWorkerThread deadlocks
- From: Chuck Hill <email@hidden>
- Date: Mon, 10 Sep 2012 10:23:52 -0700
Hi Maik,
"WorkerThread207" that many worker threads indicates two things to me:
1. Your app configuration is too high. I'd use a max of 6-10 and a listen queue size of around 4 (adjusted to suit your specific needs). A WO app is very, very unlikely to recover from a 200 worker thread backlog in any way that is useful to the users
2. You have a thread that is taking a long time to return a result. If you are dispatching requests concurrently, then this is most likely stuck in EOControl/EOAccess (e.g. waiting for a slow query result) or connecting to some external process. You could also have a deadlock. If you are not dispatching requests concurrently, then this delay could be in other code.
The traces below do not show the problem. If you want to send a full dump, I am willing to look at it. It is possible that the problem had resolved by the time you took this dump. What you show below is normal for a lot of worker threads. WorkerThread206 is waiting for a new request, WorkerThread207 is idle waiting for something to do in the future.
Chuck
On 2012-09-10, at 8:03 AM, Maik Musall wrote:
> Hi,
>
> in an app with high concurrency, the app sometimes becomes unresponsive to everything but DirectActions at the time of day with the most concurrency. All users aren't seeing responses any more. In jstack I see hundreds of these:
>
>> "WorkerThread207" prio=5 tid=131e0a800 nid=0x151aa2000 waiting for monitor entry [151aa1000]
>> java.lang.Thread.State: BLOCKED (on object monitor)
>> at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:406)
>> - waiting to lock <20d3da450> (a java.net.SocksSocketImpl)
>> at java.net.ServerSocket.implAccept(ServerSocket.java:462)
>> at java.net.ServerSocket.accept(ServerSocket.java:430)
>> at com.webobjects.appserver._private.WOWorkerThread.run(WOWorkerThread.java:210)
>> at java.lang.Thread.run(Thread.java:680)
>
> all waiting on the same lock 20d3da450, and one thread holding that lock:
>
>> "WorkerThread206" prio=5 tid=131d79800 nid=0x15199f000 runnable [15199e000]
>> java.lang.Thread.State: RUNNABLE
>> at java.net.PlainSocketImpl.socketAccept(Native Method)
>> at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:408)
>> - locked <20d3da450> (a java.net.SocksSocketImpl)
>> at java.net.ServerSocket.implAccept(ServerSocket.java:462)
>> at java.net.ServerSocket.accept(ServerSocket.java:430)
>> at com.webobjects.appserver._private.WOWorkerThread.run(WOWorkerThread.java:210)
>> at java.lang.Thread.run(Thread.java:680)
>
> Anyone familiar with this problem?
>
> Maik
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--
Chuck Hill Senior Consultant / VP Development
Practical WebObjects - for developers who want to increase their overall knowledge of WebObjects or who are trying to solve specific problems.
http://www.global-village.net/gvc/practical_webobjects
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