[jboss-user] [JBoss Cache: Core Edition] - Re: BerkeleyDB Deadlock Exception from JBoss Cache Loader: B

[niuxuetao_fiserv]

Now I have a very serious performance problem with the way (the "X/Y" way) I compose the string id when using Pojo cache.

I have one PojoCache instance globally shared by 20 threads in websphere, but those 20 threads are mostly in the "waiting" state by what I see with JProfiler, the hotspots are:
- 6.2% - 30,415 s - 9,479 hot spot inv. org.jboss.cache.util.concurrent.locks.OwnableReentrantLock.tryLock
- 2.0% - 10,057 s - 5,065 hot spot inv. org.jboss.cache.mvcc.MVCCNodeHelper.acquireLock (line: 259)

While the threads are waiting, the CPU usage is nearly zero (there are some daemon threads running periodically in websphere).

It is not a real deadlock because all processing eventually finished without. What I don't understand is that why in majority of the time those threads are waiting for each other but no one is really busy?

No matter how I compose the key, I would expect at least one thread is busy at a certain moment.


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