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From "Lars George (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HBASE-1185) wrong request/sec in the gui reporting wrong
Date Mon, 02 Mar 2009 21:44:56 GMT

    [ https://issues.apache.org/jira/browse/HBASE-1185?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12678123#action_12678123
] 

Lars George commented on HBASE-1185:
------------------------------------

HI Stack,

When I look at the code in the HRegionServer.run() I see this:

            this.serverInfo.setLoad(new HServerLoad(requestCount.get(),
                onlineRegions.size()));
            this.requestCount.set(0);

Which effectively means that this number is aggregated during the "message-interval" timeframe
of the default 3 seconds. Then it handed over to the master and reset. The master UI takes
this number and display it divided by the message-interval to get the requests per second
value.

But since this in not actually aggregating the total number of request *per* HRegionServer
it is always just a snapshot of what happened in the last three seconds. Once the job ends
and no further requests are done it drops down to zero within 3 seconds.

Which I think is OK for a gauge. But what Billy is asking for sounds like something different,
i.e. the load as an average over time - similar maybe to the unix "w" output.

Am I wrong here?

Thanks,
Lars


> wrong request/sec in the gui reporting wrong
> --------------------------------------------
>
>                 Key: HBASE-1185
>                 URL: https://issues.apache.org/jira/browse/HBASE-1185
>             Project: Hadoop HBase
>          Issue Type: Bug
>          Components: client, regionserver
>    Affects Versions: 0.19.0
>         Environment: 0.19.0
>            Reporter: Billy Pearson
>            Priority: Minor
>             Fix For: 0.20.0
>
>
> I am seeing lower number of request in the masters gui then I have seen in 0.18.0 while
scanning.
> I thank part of it is we moved to report per sec request not per 3 secs so the request
should be 1/3 of the old numbers I was getting.
> hbase.client.scanner.caching is not the reason the request are under reported.
> I set hbase.client.scanner.caching = 1 and still get about 2K request a sec in the gui
> but when the job is done I take records / job time and get 36,324/ records /sec. So
> there must be some caching out side of the hbase.client.scanner.caching making the
> request per sec lower then it should be. I know it running faster then reported just
thought
> it might give some new users the wrong impression that request/sec = read/write /sec.

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