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From "Kevin O'dell" <kevin.od...@cloudera.com>
Subject Re: Tuning HBase for random reads
Date Wed, 26 Sep 2012 16:21:06 GMT
Jon,

  I am referring to you HBase block size, NOT your HDFS block size.   You
will want to leave that at 64MB or maybe even use 128MB if this is an all
HBase cluster.  Can you do a describe on the table in question and post
that here.

On Wed, Sep 26, 2012 at 12:05 PM, Jonathan Bishop <jbishop.rwc@gmail.com>wrote:

> I am using block size in HDFS of 64MB - the default I believe. I'll try
> something smaller, say 16MB or even 4MB.
>
> I'll also give bloom filters a try, but I don't believe that will help
> because I have so few columns. Isn't bloom filtering for quick reject for
> large number of columns in a row?
>
> Thanks for the suggestions everyone.
>
> Jon
>
> On Wed, Sep 26, 2012 at 6:06 AM, Kevin O'dell <kevin.odell@cloudera.com
> >wrote:
>
> > What is your block size you are using?  Typically a smaller block size
> can
> > help with random reads, but will have a longer create time.\
> > -Kevin
> >
> > On Wed, Sep 26, 2012 at 2:18 AM, Anoop Sam John <anoopsj@huawei.com>
> > wrote:
> >
> > > Can you try with bloom filters? This can help in get()
> > > -Anoop-
> > > ________________________________________
> > > From: Jonathan Bishop [jbishop.rwc@gmail.com]
> > > Sent: Wednesday, September 26, 2012 11:34 AM
> > > To: user@hbase.apache.org
> > > Subject: Tuning HBase for random reads
> > >
> > > Hi,
> > >
> > > I am running hbase-0.92.1 and have set up a cluster of 10 machines.
> Scans
> > > performance seems great, 30K-100K rows per second, but random row reads
> > are
> > > only about 100 rows/second.
> > >
> > > My rows are not very big, just a few columns with between 4-100 bytes,
> > but
> > > my table is around 18M rows.
> > >
> > > I am pre-splitting my table and using hashing to randomize the row
> keys,
> > so
> > > I see a nice even load on the region servers.
> > >
> > > Any suggestion on things I should try?
> > >
> > > Thanks,
> > >
> > > Jon
> > >
> >
> >
> >
> > --
> > Kevin O'Dell
> > Customer Operations Engineer, Cloudera
> >
>



-- 
Kevin O'Dell
Customer Operations Engineer, Cloudera

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