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From Mujtaba Chohan <mujt...@apache.org>
Subject Re: SALT_BUCKETS
Date Thu, 09 Oct 2014 15:25:21 GMT
In addition to what Gabriel said, it also depends on kind of queries that
you would most frequently execute. If you queries are highly selective, say
the filter just aggregates 1% rows of entire table based on row key then
keeping salt buckets size low or even without salting might give better
performance as there would be fewer blocks read from disk.

For full table aggregation queries and for better write performance higher
value for salt buckets would be better.

Also note with 1tb of data and low value of salt bucket, table would
still get auto-split after region size threshold is reached based on split
policy.

//Mujtaba

On Thursday, October 9, 2014, Gabriel Reid <gabriel.reid@gmail.com> wrote:

> Hi Arthur,
>
> Each salt bucket results in a single region by default. You'll
> probably want to have more than one region per region server, although
> this can depend on a number of things. There's some good information
> on choosing the appropriate number of regions here:
> http://hbase.apache.org/book/regions.arch.html
>
> In any case, you'll want at least 5 buckets if you're working with 5
> nodes, and it's a good idea to work in multiples of 5 (i.e. 5, 10, 15,
> or 20) if you want to distribute the data relatively evenly over your
> cluster.
>
> - Gabriel
>
>
> On Thu, Oct 9, 2014 at 9:06 AM, Arthur.hk.chan@gmail.com <javascript:;>
> <arthur.hk.chan@gmail.com <javascript:;>> wrote:
> > Hi,
> >
> > I plan to use Phoenix to load in a very large transaction detail table
> (about 1TB), my HBASE cluster has 5 nodes, I plan to create a SALTED TABLE
> for it.
> >
> > 2 questions:
> > Q1) Can anyone suggest how to determine the proper value for
> SALT_BUCKETS?
> > Q2) In my case here, if I set SALT_BUCKETS = 5 (same number of HBase
> node), is it a proper setting?
> >
> > Regards
> > Arthur
> >
> >
> >
> >
>

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