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From Ey-Chih chow <eyc...@gmail.com>
Subject Re: performance of a hbase map/reduce job
Date Wed, 30 May 2012 06:48:22 GMT
It's a 3 node cluster running zookeeper-3.3.3 no modifications
have been made by us. This is separate and dedicated only for hbase.

We were looking at the ganglia graphs, not much load almost none,
traffic is 1-2kb/sec.

Thanks.

Ey-Chih Chow


On May 29, 2012, at 7:39 PM, Ted Yu wrote:

> Can you describe your zookeeper setup a little more ?
> 
> Thanks
> 
> On Tue, May 29, 2012 at 6:52 PM, Ey-Chih chow <eychih@gmail.com> wrote:
> 
>> Hi,
>> 
>> We have some performance issue with a hbase map-only job, that copies data
>> from hbase to hdfs.  We profiled the job and what follows were the top 6
>> ranked methods, in terms of CPU usages, and the corresponding traces.
>> 
>> ==========================================================================
>> 
>> CPU SAMPLES BEGIN (total = 1162350) Tue May 29 16:54:18 2012
>> rank   self  accum   count trace method
>>  1 16.67% 16.67%  193724 312698 sun.nio.ch.EPollArrayWrapper.epollWait
>>  2 16.66% 33.32%  193609 314324 sun.nio.ch.EPollArrayWrapper.epollWait
>>  3 16.65% 49.98%  193573 314044 sun.nio.ch.EPollArrayWrapper.epollWait
>>  4 16.56% 66.54%  192491 319621 sun.nio.ch.EPollArrayWrapper.epollWait
>>  5 10.90% 77.44%  126699 319206 sun.nio.ch.EPollArrayWrapper.epollWait
>>  6  5.64% 83.08%   65565 327226 sun.nio.ch.EPollArrayWrapper.epollWait
>> 
>> TRACE 312698: (thread=200010)
>> 
>> sun.nio.ch.EPollArrayWrapper.epollWait(EPollArrayWrapper.java:Unknown line)
>>       sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:210)
>>       sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:65)
>>       sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:69)
>>       sun.nio.ch.SelectorImpl.select(SelectorImpl.java:80)
>>       org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1107)
>> 
>> TRACE 314324: (thread=200015)
>> 
>> sun.nio.ch.EPollArrayWrapper.epollWait(EPollArrayWrapper.java:Unknown line)
>>       sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:210)
>>       sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:65)
>>       sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:69)
>>       sun.nio.ch.SelectorImpl.select(SelectorImpl.java:80)
>>       org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1107)
>> 
>> TRACE 314044: (thread=200013)
>> 
>> sun.nio.ch.EPollArrayWrapper.epollWait(EPollArrayWrapper.java:Unknown line)
>>       sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:210)
>>       sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:65)
>>       sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:69)
>>       sun.nio.ch.SelectorImpl.select(SelectorImpl.java:80)
>>       org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1107)
>> 
>> TRACE 319621: (thread=200023)
>> 
>> sun.nio.ch.EPollArrayWrapper.epollWait(EPollArrayWrapper.java:Unknown line)
>>       sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:210)
>>       sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:65)
>>       sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:69)
>>       sun.nio.ch.SelectorImpl.select(SelectorImpl.java:80)
>>       org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1107)
>> 
>> TRACE 319206: (thread=200022)
>> 
>> sun.nio.ch.EPollArrayWrapper.epollWait(EPollArrayWrapper.java:Unknown line)
>>       sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:210)
>>       sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:65)
>>       sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:69)
>>       sun.nio.ch.SelectorImpl.select(SelectorImpl.java:80)
>> 
>> org.apache.hadoop.net.SocketIOWithTimeout$SelectorPool.select(SocketIOWithTimeout.java:332)
>> 
>> TRACE 327226: (thread=200101)
>> 
>> sun.nio.ch.EPollArrayWrapper.epollWait(EPollArrayWrapper.java:Unknown line)
>>       sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:210)
>>       sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:65)
>>       sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:69)
>>       sun.nio.ch.SelectorImpl.select(SelectorImpl.java:80)
>> 
>> org.apache.hadoop.net.SocketIOWithTimeout$SelectorPool.select(SocketIOWithTimeout.java:332)
>> 
>> ===============================================================
>> 
>> Looks like the problem may be related to Zookeeper connections.  Is there
>> anybody knows how to improve the performance of the job?  Thanks.
>> 
>> Ey-Chih Chow


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