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Posted to issues@hbase.apache.org by "Guanghao Zhang (JIRA)" <ji...@apache.org> on 2016/10/14 10:38:21 UTC
[jira] [Updated] (HBASE-16815) Low scan ratio in RPC queue tuning
triggers divide by zero exception
[ https://issues.apache.org/jira/browse/HBASE-16815?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Guanghao Zhang updated HBASE-16815:
-----------------------------------
Status: Patch Available (was: Open)
> Low scan ratio in RPC queue tuning triggers divide by zero exception
> --------------------------------------------------------------------
>
> Key: HBASE-16815
> URL: https://issues.apache.org/jira/browse/HBASE-16815
> Project: HBase
> Issue Type: Bug
> Components: regionserver, rpc
> Affects Versions: 2.0.0, 1.3.0
> Reporter: Lars George
> Attachments: HBASE-16815.patch
>
>
> Trying the following settings:
> {noformat}
> <property>
> <name>hbase.ipc.server.callqueue.handler.factor</name>
> <value>0.5</value>
> </property>
> <property>
> <name>hbase.ipc.server.callqueue.read.ratio</name>
> <value>0.5</value>
> </property>
> <property>
> <name>hbase.ipc.server.callqueue.scan.ratio</name>
> <value>0.1</value>
> </property>
> {noformat}
> With 30 default handlers, this means 15 queues. Further, it means 8 write queues and 7 read queues. 10% of that is {{0.7}} which is then floor'ed to {{0}}. The debug log confirms it, as the tertiary check omits the scan details when they are zero:
> {noformat}
> 2016-10-12 12:50:27,305 INFO [main] ipc.SimpleRpcScheduler: Using fifo as user call queue, count=15
> 2016-10-12 12:50:27,311 DEBUG [main] ipc.RWQueueRpcExecutor: FifoRWQ.default writeQueues=7 writeHandlers=15 readQueues=8 readHandlers=14
> {noformat}
> But the code in {{RWQueueRpcExecutor}} calls {{RpcExecutor.startHandler()}} nevertheless and that does this:
> {code}
> for (int i = 0; i < numHandlers; i++) {
> final int index = qindex + (i % qsize);
> String name = "RpcServer." + threadPrefix + ".handler=" + handlers.size() + ",queue=" +
> index + ",port=" + port;
> {code}
> The modulo triggers then
> {noformat}
> 2016-10-12 11:41:22,810 ERROR [main] master.HMasterCommandLine: Master exiting
> java.lang.RuntimeException: Failed construction of Master: class org.apache.hadoop.hbase.master.HMasterCommandLine$LocalHMaster
> at org.apache.hadoop.hbase.util.JVMClusterUtil.createMasterThread(JVMClusterUtil.java:145)
> at org.apache.hadoop.hbase.LocalHBaseCluster.addMaster(LocalHBaseCluster.java:220)
> at org.apache.hadoop.hbase.LocalHBaseCluster.(LocalHBaseCluster.java:155)
> at org.apache.hadoop.hbase.master.HMasterCommandLine.startMaster(HMasterCommandLine.java:222)
> at org.apache.hadoop.hbase.master.HMasterCommandLine.run(HMasterCommandLine.java:137)
> at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
> at org.apache.hadoop.hbase.util.ServerCommandLine.doMain(ServerCommandLine.java:126)
> at org.apache.hadoop.hbase.master.HMaster.main(HMaster.java:2524)
> Caused by: java.lang.ArithmeticException: / by zero
> at org.apache.hadoop.hbase.ipc.RpcExecutor.startHandlers(RpcExecutor.java:125)
> at org.apache.hadoop.hbase.ipc.RWQueueRpcExecutor.startHandlers(RWQueueRpcExecutor.java:178)
> at org.apache.hadoop.hbase.ipc.RpcExecutor.start(RpcExecutor.java:78)
> at org.apache.hadoop.hbase.ipc.SimpleRpcScheduler.start(SimpleRpcScheduler.java:272)
> at org.apache.hadoop.hbase.ipc.RpcServer.start(RpcServer.java:2212)
> at org.apache.hadoop.hbase.regionserver.RSRpcServices.start(RSRpcServices.java:1143)
> at org.apache.hadoop.hbase.regionserver.HRegionServer.(HRegionServer.java:615)
> at org.apache.hadoop.hbase.master.HMaster.(HMaster.java:396)
> at org.apache.hadoop.hbase.master.HMasterCommandLine$LocalHMaster.(HMasterCommandLine.java:312)
> at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
> at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
> at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
> at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
> at org.apache.hadoop.hbase.util.JVMClusterUtil.createMasterThread(JVMClusterUtil.java:140)
> ... 7 more
> {noformat}
> That causes the server to not even start. I would suggest we either skip the {{startHandler()}} call altogether, or make it zero aware.
> Another possible option is to reserve at least _one_ scan handler/queue when the scan ratio is greater than zero, but only of there is more than one read handler/queue to begin with. Otherwise the scan handler/queue should be zero and share the one read handler/queue.
> Makes sense?
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