Jean-Daniel Cryans created HBASE-6309: -----------------------------------------
Summary: [MTTR] Do NN operations outside of the ZK EventThread in SplitLogManager Key: HBASE-6309 URL: https://issues.apache.org/jira/browse/HBASE-6309 Project: HBase Issue Type: Improvement Affects Versions: 0.94.0, 0.92.1, 0.96.0 Reporter: Jean-Daniel Cryans Priority: Critical Fix For: 0.96.0 We found this issue during the leap second cataclysm which prompted a distributed splitting of all our logs. I saw that none of the RS were splitting after some time while the master was showing that it wasn't even 30% done. jstack'ing I saw this: {noformat} "main-EventThread" daemon prio=10 tid=0x00007f6ce46d8800 nid=0x5376 in Object.wait() [0x00007f6ce2ecb000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) at java.lang.Object.wait(Object.java:485) at org.apache.hadoop.ipc.Client.call(Client.java:1093) - locked <0x00000005fdd661a0> (a org.apache.hadoop.ipc.Client$Call) at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:226) at $Proxy9.rename(Unknown Source) at sun.reflect.GeneratedMethodAccessor29.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:82) at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:59) at $Proxy9.rename(Unknown Source) at org.apache.hadoop.hdfs.DFSClient.rename(DFSClient.java:759) at org.apache.hadoop.hdfs.DistributedFileSystem.rename(DistributedFileSystem.java:253) at org.apache.hadoop.hbase.regionserver.wal.HLogSplitter.moveRecoveredEditsFromTemp(HLogSplitter.java:553) at org.apache.hadoop.hbase.regionserver.wal.HLogSplitter.moveRecoveredEditsFromTemp(HLogSplitter.java:519) at org.apache.hadoop.hbase.master.SplitLogManager$1.finish(SplitLogManager.java:138) at org.apache.hadoop.hbase.master.SplitLogManager.getDataSetWatchSuccess(SplitLogManager.java:431) at org.apache.hadoop.hbase.master.SplitLogManager.access$1200(SplitLogManager.java:95) at org.apache.hadoop.hbase.master.SplitLogManager$GetDataAsyncCallback.processResult(SplitLogManager.java:1011) at org.apache.zookeeper.ClientCnxn$EventThread.processEvent(ClientCnxn.java:571) at org.apache.zookeeper.ClientCnxn$EventThread.run(ClientCnxn.java:497) {noformat} We are effectively bottlenecking on doing NN operations and whatever else is happening in GetDataAsyncCallback. It was so bad that on our 100 offline cluster it took a few hours for the master to process all the incoming ZK events while the actual splitting took a fraction of that time. I'm marking this as critical and against 0.96 but depending on how involved the fix is we might want to backport. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira