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From "Azuryy Yu (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HBASE-7251) Avoid flood logs during client disconnect during batch get operation
Date Sat, 01 Dec 2012 14:33:58 GMT

     [ https://issues.apache.org/jira/browse/HBASE-7251?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Azuryy Yu updated HBASE-7251:

    Attachment:     (was: HBASE-7251.patch)
> Avoid flood logs during client disconnect during batch get operation
> --------------------------------------------------------------------
>                 Key: HBASE-7251
>                 URL: https://issues.apache.org/jira/browse/HBASE-7251
>             Project: HBase
>          Issue Type: Bug
>    Affects Versions: 0.94.2
>            Reporter: Azuryy Yu
>              Labels: patch
>             Fix For: 0.94.3
>         Attachments: HBASE-7251.patch
> Background:
> A smart guy in the company want to read data from the HBASE in batch, the code like the
following:(just demonstrate, not runnable):
> 	List<Get> gets = new ArrayList<Get>();
> 	for(int i =0; i < n; ++i){
> 		gets.add("some row key here");
> 		if (i % 10000 == 0){
> 			Results[] results = htable.get(gets);
> 			//process results here.  so delete some code
> 		}
> 	}
> Yes, you know that, this guy forgot "gets.clear()"  after each "htable.get()" operation
in his code.
> One region server becomes very slow, and crashed after 30mins becauseof OOM, but we got
15GB log file.
> there are flood logs as following:
> ERROR org.apache.hadoop.hbase.regionserver.HRegionServer:
> org.apache.hadoop.hbase.ipc.CallerDisconnectedException: Aborting call multi(org.apache.hadoop.hbase.client.MultiAction@49540d8d),
rpc version=1, client version=29, methodsFingerPrint=-56040613 from after 3980
ms, since caller disconnected
>         at org.apache.hadoop.hbase.ipc.HBaseServer$Call.throwExceptionIfCallerDisconnected(HBaseServer.java:436)
>         at org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.nextInternal(HRegion.java:3468)
>         at org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.next(HRegion.java:3425)
>         at org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.next(HRegion.java:3449)
>         at org.apache.hadoop.hbase.regionserver.HRegion.get(HRegion.java:4198)
>         at org.apache.hadoop.hbase.regionserver.HRegion.get(HRegion.java:4171)
>         at org.apache.hadoop.hbase.regionserver.HRegionServer.get(HRegionServer.java:1993)
>         at org.apache.hadoop.hbase.regionserver.HRegionServer.multi(HRegionServer.java:3410)
>         at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>         at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
>         at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
>         at java.lang.reflect.Method.invoke(Method.java:601)
>         at org.apache.hadoop.hbase.ipc.WritableRpcEngine$Server.call(WritableRpcEngine.java:364)
>         at org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:1409)
> Fix:
> Server is stop "get" but cannot exit from the "for" loop, so write flood logs here.
> My patch just log one exception log instead of flood logs. 
> Importantly, server stop processing immediately if client timeout or disconnect.
> Test:
> I used this guy's wrong code read data( NO "gets.clear()" ) from the HBASE, when it becomes
very slow to get results, I pressed ctrl+C, then there is only ONE CallerDisconnectedException
exception log and the server stop reading immediately, LOG generate the last log entry:
>  WARN org.apache.hadoop.ipc.HBaseServer: IPC Server handler 1 on 60020 caught a ClosedChannelException,
this means that the server was processing a request but the client went away. The error message
was: null

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