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From ramkrishna vasudevan <ramkrishna.s.vasude...@gmail.com>
Subject Re: Question about RPC queues
Date Fri, 04 Sep 2015 16:05:00 GMT
Hi Kulkarni

Which version of HBase are you using?  Just to confirm are you running as
super user only?  I think there are some meta handlers also with which
super user calls are handled.

>From the UI are you able to monitor the handlers and see how many are
active and what is the status of it.


On Fri, Sep 4, 2015 at 7:42 PM, kulkarni.swarnim@gmail.com <
kulkarni.swarnim@gmail.com> wrote:

> Hello all,
> So I am trying to play around with de-prioritizing long running scanners
> feature added with HBASE-10993. Essentially I wanted to see how "deadline"
> queue prevents contention. This is what my did for my setup. Changed the
> callqueue type to "fifo" and reduced the number of RPC handlers to 1 to
> ensure that I have only one RPC queue in place. I am also testing on a
> cluster with only one RS to again make sure that there is only one RPC
> handler working. I confirmed that my settings are properly in place with
> the following message in the hmaster logs after I restarted my cluster.
> "INFO org.apache.hadoop.hbase.ipc.SimpleRpcScheduler: Using fifo as user
> call queue, count=1"
> I now kicked off a long running "scan" first and while the scan was running
> kicked off another "get". My hope was that with fifo, we should see a
> contention and the "get" would essentially hang until the "scan" finished
> as it would be placed behind the "scan" request in the RPC queue. But I see
> the gets still return quickly irrespective of whether the scan is running
> or not.
> Is there something obvious that I am missing here to be able to reproduce
> the contention?
> Thanks,
> Swarnim

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