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HBase, mail # user - Bulk Loads and Updates


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RE: Bulk Loads and Updates
Ramkrishna.S.Vasudevan 2012-10-04, 04:23
Which version of HBASE are you using?

As part of HBASE-5564 a feature was introduced to handle duplicate records
in bulk load using timestamp also to be specified in the file like how we
specify the column family and table name.

If you can backport it to your version hope it will be helpful.

Regards
Ram

> -----Original Message-----
> From: Eugeny Morozov [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, October 04, 2012 2:01 AM
> To: [EMAIL PROTECTED]
> Subject: Re: Bulk Loads and Updates
>
> Hi!
>
> Sure, you do, but don't forget to sort all KV pairs before put them
> into
> context. Or else you'd get some "unsorted" expection.
>
> If you have them completely the same and you need to reduce number of
> same
> lines you could use Combiner, but their behavior is not deterministic,
> so
> basically there is no guarantee that it'll be run and how many times.
>
>
> On Thu, Oct 4, 2012 at 12:22 AM, gordoslocos <[EMAIL PROTECTED]>
> wrote:
>
> > Thank you Paul.
> >
> > I was just thinking that I could use add a reducer to the step that
> > prepares the data to build custom logic around having multiple
> entries
> > which produce the same rowkey. What do u think?
> >
> > Sent from my iPhone
> >
> > On 03/10/2012, at 17:12, Paul Mackles <[EMAIL PROTECTED]> wrote:
> >
> > > Keys in hbase are a combination of rowkey/column/timestamp.
> > >
> > > Two records with the same rowkey but different column will result
> in two
> > > different cells with the same rowkey which is probably what you
> expect.
> > >
> > > For two records with the same rowkey and same column, the timestamp
> will
> > > normally differentiate them but in the case of a bulk load, the
> timestamp
> > > could be the same so it may actually be a tie and both will be
> stored.
> > > There are no updates in bulk loads.
> > >
> > > All 20 versions will get loaded but the 10 oldest will be deleted
> during
> > > the next major compaction.
> > >
> > > I would definitely recommend setting up small scale tests for all
> of the
> > > above scenarios to confirm.
> > >
> > > On 10/3/12 3:35 PM, "Juan P." <[EMAIL PROTECTED]> wrote:
> > >
> > >> Hi guys,
> > >> I've been reading up on bulk load using MapReduce jobs and I
> wanted to
> > >> validate something.
> > >>
> > >> If I the input I wanted to load into HBase produced the same key
> for
> > >> several lines. How will HBase handle that?
> > >>
> > >> I understand the MapReduce job will create StoreFiles which the
> region
> > >> servers just pick up and make available to the users. But is there
> a
> > >> validation to treat the first as insert and the rest as updates?
> > >>
> > >> What about the limit on the number of versions of a key HBase can
> have?
> > If
> > >> I want to have 10 versions, but the bulk load has 20 values for
> the same
> > >> key, will it only keep the last 10?
> > >>
> > >> Thanks,
> > >> Juan
> > >
> >
>
>
>
> --
> Evgeny Morozov
> Developer Grid Dynamics
> Skype: morozov.evgeny
> www.griddynamics.com
> [EMAIL PROTECTED]