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HBase, mail # user - experiencing high latency for few reads in HBase


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Saurabh Yahoo 2013-08-28, 12:10
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Vladimir Rodionov 2013-08-28, 19:15
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Saurabh Yahoo 2013-08-28, 22:17
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lars hofhansl 2013-08-29, 04:29
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Federico Gaule 2013-08-29, 12:37
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Saurabh Yahoo 2013-08-29, 17:47
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Kiru Pakkirisamy 2013-08-30, 02:45
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Adrien Mogenet 2013-08-30, 06:11
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Kiru Pakkirisamy 2013-08-30, 08:36
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Kiru Pakkirisamy 2013-08-28, 20:30
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Saurabh Yahoo 2013-08-28, 22:20
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Kiru Pakkirisamy 2013-08-28, 23:01
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Saurabh Yahoo 2013-08-28, 23:18
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Vladimir Rodionov 2013-08-29, 00:10
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Saurabh Yahoo 2013-08-29, 09:49
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Kiru Pakkirisamy 2013-08-29, 15:59
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Saurabh Yahoo 2013-08-29, 17:49
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Vladimir Rodionov 2013-08-29, 16:17
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Saurabh Yahoo 2013-08-29, 17:52
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Re: experiencing high latency for few reads in HBase
Bryan Beaudreault 2013-08-29, 17:55
If you lost a RS or otherwise moved a region around (hbase balancer?) then
it would throw off the locality.  You'll want to compact any time a region
moves for any reason (unless it moved to another RS with which it had
locality).  Try major compacting again now and see if the locality index
goes up to 100
On Thu, Aug 29, 2013 at 1:52 PM, Saurabh Yahoo <[EMAIL PROTECTED]> wrote:

> Thanks Vlad.
>
> Quick question. I notice hdfsBlocksLocalityIndex is around 50 in all
> region servers.
>
> Does that could be a problem? If it is, how to solve that? We already ran
> the major compaction after ingesting the data.
>
> Thanks,
> Saurabh.
>
> On Aug 29, 2013, at 12:17 PM, Vladimir Rodionov <[EMAIL PROTECTED]>
> wrote:
>
> > Yes. HBase won't guarantee strict sub-second latency.
> >
> > Best regards,
> > Vladimir Rodionov
> > Principal Platform Engineer
> > Carrier IQ, www.carrieriq.com
> > e-mail: [EMAIL PROTECTED]
> >
> > ________________________________________
> > From: Saurabh Yahoo [[EMAIL PROTECTED]]
> > Sent: Thursday, August 29, 2013 2:49 AM
> > To: [EMAIL PROTECTED]
> > Cc: [EMAIL PROTECTED]
> > Subject: Re: experiencing high latency for few reads in HBase
> >
> > Hi Vlad,
> >
> > We do have strict latency requirement as it is financial data requiring
> direct access from clients.
> >
> > Are you saying that it is not possible to achieve sub second latency
> using hbase (because it is based on java.) ?
> >
> >
> >
> >
> >
> >
> >
> > On Aug 28, 2013, at 8:10 PM, Vladimir Rodionov <[EMAIL PROTECTED]>
> wrote:
> >
> >> Increasing Java heap size will make latency worse, actually.
> >> You can't guarantee 1 sec max latency if run Java app (unless your heap
> size is much less than 1GB).
> >> I have never heard about strict maximum latency limit. Usually , its
> 99% , 99.9 or 99.99% query percentiles.
> >>
> >> You can greatly reduce your 99.xxx% percentile latency by storing you
> data in 2 replicas to two different region servers.
> >> Issue two read operations to those two region servers in parallel and
> get the first response. Probability theory states that  probability
> >> of two independent events (slow requests) is  the product of event's
> probabilities themselves.
> >>
> >>
> >> Best regards,
> >> Vladimir Rodionov
> >> Principal Platform Engineer
> >> Carrier IQ, www.carrieriq.com
> >> e-mail: [EMAIL PROTECTED]
> >>
> >> ________________________________________
> >> From: Saurabh Yahoo [[EMAIL PROTECTED]]
> >> Sent: Wednesday, August 28, 2013 4:18 PM
> >> To: [EMAIL PROTECTED]
> >> Subject: Re: experiencing high latency for few reads in HBase
> >>
> >> Thanks Kiru,
> >>
> >> Scan is not an option for our use cases.  Our read is pretty random.
> >>
> >> Any other suggestion to bring down the latency.
> >>
> >> Thanks,
> >> Saurabh.
> >>
> >>
> >> On Aug 28, 2013, at 7:01 PM, Kiru Pakkirisamy <
> [EMAIL PROTECTED]> wrote:
> >>
> >>> Saurabh, we are able to 600K rowxcolumns in 400 msec. We have put what
> was a 40million row table as 400K rows and columns. We Get about 100 of the
> rows from this 400K , do quite a bit of calculations in the coprocessor
> (almost a group-order by) and return in this time.
> >>> Maybe should consider replacing the MultiGets with Scan with Filter. I
> like the FuzzyRowFilter even though you might need to match with exact key.
> It works only with fixed length key.
> >>> (I do have an issue right now, it is not scaling to multiple clients.)
> >>>
> >>> Regards,
> >>> - kiru
> >>>
> >>>
> >>> Kiru Pakkirisamy | webcloudtech.wordpress.com
> >>>
> >>>
> >>> ________________________________
> >>> From: Saurabh Yahoo <[EMAIL PROTECTED]>
> >>> To: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> >>> Cc: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> >>> Sent: Wednesday, August 28, 2013 3:20 PM
> >>> Subject: Re: experiencing high latency for few reads in HBase
> >>>
> >>>
> >>> Thanks Kitu. We need less than 1 sec latency.
> >>>
> >>> We are using both muliGet and get.
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Vladimir Rodionov 2013-08-29, 18:11
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Kiru Pakkirisamy 2013-08-29, 18:33
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Saurabh Yahoo 2013-08-29, 19:09
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Kiru Pakkirisamy 2013-08-29, 19:27
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Adrien Mogenet 2013-08-29, 20:07
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Saurabh Yahoo 2013-08-29, 20:58
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Vladimir Rodionov 2013-08-28, 19:18