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Zookeeper >> mail # user >> High CPU utilization by zookeeper

Glushak, Vladimir 2013-07-23, 20:51
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High CPU utilization by zookeeper
Hello Zookeeper community,

I've found that our application has issue with high CPU usage.
I've done some profiling and found out that root cause of this issue is thread responsible for connecting to zookeeper.
After some more investigation, i've found out that my application (one process) has few separate sessions (clients ) that connect to zookeeper. I've refactored it and decrease number of sessions to 1.

The CPU usage decreased. But still thread responsible for interaction with zoo-server is consuming a lot of resources:
        7,044,378.96 [ms]
        984.896 ms / sec
The application is currently in "sleep mode" - it does nothing, but this thread is really busy. Should it be such?
I've found out that this thread is currently works in infinity loop:
com.db.itrac.router.context.SendThread -> run method, especially  < clientCnxnSocket.doTransport(to, pendingQueue, outgoingQueue);  >  consumes most of resources.
To connecting zookeeper I'm using netflix CuratorFramework with default configuration. Maybe I'm doing smth wrong, please advice?
Also I have two questions:

1. Should such high CPU consumption thread exists in app? Is it proper behavior?
2. Can one application has few separate sessions to zookeeper server? Is it expected behavior to increase of CPU utilization?

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Sergey Maslyakov 2013-07-24, 05:17