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From Arun Allamsetty <arun.allamse...@gmail.com>
Subject Re: Why hbase need manual split?
Date Wed, 06 Aug 2014 06:44:03 GMT
Hi Ming,

The reason why we have it is because the user can decide where each key
goes. I can think multiple scenarios off the top of my head where it would
be useful and others can correct me if I am wrong.

1. Cases where you cannot have row keys which are equally lexically
distributed, leading in unequal loads on the regions. In such cases, we can
set key ranges to be assigned to different regions so that we can have a
more equal distribution.

2. The second scenario I am thinking of may be wrong and if it is, it'll
clear my misconceptions. In case you cannot denormalize your data and you
have to perform joins on certain range of row keys which are lexically
similar. So we split them and they would be assigned to the same region
server (right?) and the join would be performed locally.

Cheers,
Arun

Sent from a mobile device. Please don't mind the typos.
On Aug 6, 2014 12:30 AM, "Liu, Ming (HPIT-GADSC)" <ming.liu2@hp.com> wrote:

> Hi, all,
>
> As I understand, HBase will automatically split a region when the region
> is too big.
> So in what scenario, user needs to do a manual split? Could someone kindly
> give me some examples that user need to do the region split explicitly via
> HBase Shell or Java API?
>
> Thanks very much.
>
> Regards,
> Ming
>

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