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HBase, mail # dev - HBase Map/Reduce Data Ingest Performance


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Re: HBase Map/Reduce Data Ingest Performance
Nick Dimiduk 2012-12-18, 19:20
Please forgive my poor choice of words; I meant no disrespect.

-n

On Tue, Dec 18, 2012 at 11:06 AM, Upender K. Nimbekar <
[EMAIL PROTECTED]> wrote:

> I would like to request you maintain the respect of people asking questions
> on this forum. Let's not start the thread in the wrong direction.
> I wish it was a dumb question. I did chmod 777 prior to calling bulkLoad.
> Call succeeded but bulkLoad call still threw exception. However, it does
> work if I do chmod and bulkLoad() from Hadoop Driver after the job is
> finished.
> BTW, Hbase user needs a WRITE permission and NOT read bease it created some
> _tmp directories.
>
> Upen
>
> On Tue, Dec 18, 2012 at 12:31 PM, Nick Dimiduk <[EMAIL PROTECTED]> wrote:
>
> > Dumb question: what's the filesystem permissions of your generated
> HFiles?
> > Can the HBase process read them? Maybe a simple chmod or chown will get
> you
> > the rest of the way there.
> >
> > On Mon, Dec 17, 2012 at 6:30 PM, Upender K. Nimbekar <
> >  [EMAIL PROTECTED]> wrote:
> >
> > > Thanks ! I'm calling doBulkLoad() from mapper cleanup() method. But
> > running
> > > into permission issues while hbase user tries to import Hfile into
> Hbase.
> > > Not sure, if there is way to change the target HDFS file permission via
> > > HFileOutputFormat.
> > >
> > >
> > > On Mon, Dec 17, 2012 at 7:52 PM, Ted Yu <[EMAIL PROTECTED]> wrote:
> > >
> > > > I think second approach is better.
> > > >
> > > > Cheers
> > > >
> > > > On Mon, Dec 17, 2012 at 11:11 AM, Upender K. Nimbekar <
> > > > [EMAIL PROTECTED]> wrote:
> > > >
> > > > > Sure. I can try that. Just curious, out of these 2 strategies,
> which
> > > one
> > > > do
> > > > > you thin is better ? Do you have any experience of trying one or
> the
> > > > other
> > > > > ?
> > > > >
> > > > > Thanks
> > > > > Upen
> > > > >
> > > > > On Mon, Dec 17, 2012 at 12:45 PM, Ted Yu <[EMAIL PROTECTED]>
> > wrote:
> > > > >
> > > > > > Thanks for sharing your experiences.
> > > > > >
> > > > > > Have you considered upgrading to HBase 0.92 or 0.94 ?
> > > > > > There have been several bug fixes / enhancements
> > > > > > to LoadIncrementHFiles.bulkLoad() API in newer HBase releases.
> > > > > >
> > > > > > Cheers
> > > > > >
> > > > > > On Mon, Dec 17, 2012 at 7:34 AM, Upender K. Nimbekar <
> > > > > > [EMAIL PROTECTED]> wrote:
> > > > > >
> > > > > > > Hi All,
> > > > > > > I have question about improving the Map / Reduce job
> performance
> > > > while
> > > > > > > ingesting huge amount of data into Hbase using
> HFileOutputFormat.
> > > > Here
> > > > > is
> > > > > > > what we are using:
> > > > > > >
> > > > > > > 1) *Cloudera hadoop-0.20.2-cdh3u*
> > > > > > > 2) *hbase-0.90.40cdh3u2*
> > > > > > >
> > > > > > > I've used 2 different strategies as described below:
> > > > > > >
> > > > > > > *Strategy#1:* PreSplit the number of regions with 10 regions
> per
> > > > region
> > > > > > > server. And then subsequently kick off the hadoop job with
> > > > > > > HFileOutputFormat.configureIncrementLoad. This mchanism does
> > create
> > > > > > reduce
> > > > > > > tasks equal to the number of regions * 10. We used the "hash"
> of
> > > each
> > > > > > > record as the Key to Mapoutput. This process resulted in each
> > > mapper
> > > > > > finish
> > > > > > > process in accepetable amount of time. But the reduce task
> takes
> > > > > forever
> > > > > > to
> > > > > > > finish. We found that first the copy/shuffle process too
> > > condierable
> > > > > > amoun
> > > > > > > of time and then the sort process took foreever to finish.
> > > > > > > We tried to address this issue by constructing the key as
> > > > > > > "fixedhash1"_"hash2" where "fixedhash1" is fixed for all the
> > > records
> > > > > of a
> > > > > > > gven mapper. The idea was to reduce shuffling / copying from
> each
> > > > > mapper.
> > > > > > > But even this solution didn't save us anytime and the reduce
> step
> > > > took
> > > > > > > significant amount to finish. I played with adjusting the