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From Jean-Marc Spaggiari <jean-m...@spaggiari.org>
Subject Re: BulkLoad 200GB table with one region. Is it OK?
Date Thu, 02 Oct 2014 21:00:40 GMT
If it's a sigle 200GB file, when HBase will spit this region,this file will
have to be splitted and re-written into 2 x 100GB files.

How is the file generated? You should really think about splitting it
first...

2014-10-02 15:49 GMT-04:00 Jerry He <jerryjch@gmail.com>:

> The reference files will be rewritten during compaction, which normally
> happens right after splits.
>
> You did not mention if your 200gb data is one fileļ¼Œor many hfiles.
>
> Jerry
> On Oct 2, 2014 12:26 PM, "Serega Sheypak" <serega.sheypak@gmail.com>
> wrote:
>
> > Sorry, massive IO.
> > This table is read-only. So hbase should just place reference files, why
> > Hbase would rewrite the files?
> >
> > 2014-10-02 23:24 GMT+04:00 Serega Sheypak <serega.sheypak@gmail.com>:
> >
> > > Hi!
> > > http://hortonworks.com/blog/apache-hbase-region-splitting-and-merging/
> > > Says that splitting is just a placing 'reference' file.
> > > Why there sould be massive splitting?
> > >
> > > 2014-10-02 23:08 GMT+04:00 Jean-Marc Spaggiari <
> jean-marc@spaggiari.org
> > >:
> > >
> > >> Hi Serega,
> > >>
> > >> Bulk load just "push" the file into an HBase region, so there should
> not
> > >> be
> > >> any issue. Split however might take some time because HBase will have
> to
> > >> split it again and again util it become small enough. So if you max
> file
> > >> size is 10GB, it will split it to 100GB then 50GB then 25GB then 12GB
> > then
> > >> 6GB... Each time, everything will be re-written. a LOT of wasted IOs.
> > >>
> > >> So response is: Yes, HBase can handle BUT it's not a good practice.
> > Better
> > >> to split the table before and generate the bulk based on the splited
> > >> regions. Also, it might affect the others tables and the performances
> > >> because HBase will have to do massive IOs, which at the end might
> impact
> > >> the performances.
> > >>
> > >> JM
> > >>
> > >> 2014-10-02 15:03 GMT-04:00 Serega Sheypak <serega.sheypak@gmail.com>:
> > >>
> > >> > Hi, I'm doing HBase bulk load to an empty table.
> > >> > Input data size is 200GB
> > >> > Is it OK to load data into one default region and then wait while
> > HBase
> > >> > splits 200GB region?
> > >> >
> > >> > I don't have any SLA for initial load. I can wait unitl HBase splits
> > >> > initial load files.
> > >> > This table is READ only.
> > >> >
> > >> > The only conideration is not affect others tables and do not cause
> > HBase
> > >> > cluster degradation.
> > >> >
> > >>
> > >
> > >
> >
>

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