By the way, the number of maximal client connections is set to default value, i.e. 60. Does this matter? Thanks.
Ey-Chih Chow On May 29, 2012, at 11:48 PM, Ey-Chih chow wrote: > 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 <[email protected]> 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 >
