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From Michael Segel <michael_se...@hotmail.com>
Subject RE: Best way to get multiple non-sequential rows
Date Wed, 25 Aug 2010 10:53:54 GMT

Jonathan,

Ok, that makes some sense...
So you would have some method mget(fetchKeyList,numthreads) returning resultList[].

So what's thread safe these days? 

-Mike

> From: jgray@facebook.com
> To: user@hbase.apache.org
> Subject: RE: Best way to get multiple non-sequential rows
> Date: Wed, 25 Aug 2010 03:52:38 +0000
> 
> Michael,
> 
> MultiGet is about performing a set of Get operations in parallel from the client.  So
it buys you potential performance benefits from the concurrency/distribution of your operations.
> 
> Roughly, you would bucket the gets according to their region and regionserver.  Then
spawn a thread for each RS and fire off the Gets concurrently.
> 
> If I have 100 Gets to perform on a random set of keys, assuming each get takes 10ms,
doing them sequentially will take 1 second.  Other factors and RS concurrency aside, with
MultiGet on a 10 node cluster, the total time would be reduced to 100ms. With 50 nodes, 20ms.
> 
> JG
> 
> 
> > -----Original Message-----
> > From: Michael Segel [mailto:michael_segel@hotmail.com]
> > Sent: Tuesday, August 24, 2010 7:53 PM
> > To: user@hbase.apache.org
> > Subject: RE: Best way to get multiple non-sequential rows
> > 
> > 
> > Igor,
> > 
> > What does this really buy you?
> > 
> > I'm trying to figure out a use case that would show a benefit from just
> > fetching the rows individually. Since the rows are not contiguous, the
> > odds of the next row you want being in cache are going to slight to
> > most likely not. ;-)
> > 
> > Can you give a use case where having a 'multi-get' will make life
> > easier?
> > 
> > Thx
> > 
> > -Mike
> > 
> > 
> > > Date: Wed, 25 Aug 2010 07:17:13 +0600
> > > Subject: Re: Best way to get multiple non-sequential rows
> > > From: imyousuf@gmail.com
> > > To: user@hbase.apache.org
> > >
> > > Thanks Igor, I will have a look at it.
> > >
> > > /Imran
> > >
> > > On Tue, Aug 24, 2010 at 10:36 PM, Igor Ranitovic <iranitov@gmail.com>
> > wrote:
> > > > Take a look at
> > > > https://issues.apache.org/jira/browse/HBASE-1845
> > > >
> > > > As an HBase user, multi gets is something that I have been looking
> > forward
> > > > to for some time now. If there is enough interest it would be great
> > if this
> > > > becomes part of 0.90.
> > > >
> > > > Take care,
> > > > i.
> > > >
> > > > Imran M Yousuf wrote:
> > > >>
> > > >> Hi,
> > > >>
> > > >> I am using the HBase client API to interact with HBase. I have
> > noticed
> > > >> that HTableInterface has operations such as put(List<Put>),
> > > >> delete(List<Delete>), but there is no similar method for Get.
> > Using
> > > >> scan it is possible to load a range of rows, i.e. sequential rows.
> > My
> > > >> question is -
> > > >> how would it be most efficient to load N non-sequential rows?
> > > >>
> > > >> Currently I am using get(Get) method N times.
> > > >>
> > > >
> > > >
> > >
> > >
> > >
> > > --
> > > Imran M Yousuf
> > > Blog: http://imyousuf-tech.blogs.smartitengineering.com/
> > > Mobile: +880-1711402557
> > 
 		 	   		  
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