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From Christopher Schultz <ch...@christopherschultz.net>
Subject Re: Tomcat thread dump analysis
Date Wed, 08 May 2013 21:16:32 GMT
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Charles,

On 5/8/13 1:57 PM, Charles Richard wrote:
> I appreciate the friendly feedback! How do I show a lock? I don't
> see any threads that have a "BLOCKED" status. I do get this when I
> do a grep:
> 
> [root@web01 stacks]# grep locked tomcat1_20130507_14\:38.stack | wc
> -l 154
> 
> My connection pool is 150 and I do see 150 locks in the following
> type scenario which has a "locked":
> 
> "TP-Processor416" daemon prio=10 tid=0x00002aff2939a800 nid=0x5ae7
> in Object.wait() [0x00002aff632ae000] java.lang.Thread.State:
> WAITING (on object monitor) at java.lang.Object.wait(Native
> Method) - waiting on <0x00002afe240fbc58> (a 
> com.mchange.v2.resourcepool.BasicResourcePool)

This only tells you the identity of the object monitor (the "lock").
What you are missing is the identities of the object monitors already
held by this and other threads. I believe your thread dump does not
include any of these.

IIRC, the Oracle JVM can (when prodded) produce a thread dump which
includes deadlock detection and will show the suspected-deadlocked
threads, the held lock ids and what threads are waiting on.

Perhaps you can get a "better" thread dump via other means? How did
you get the one you have now?

- -chris
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