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From James Taylor <jamestay...@apache.org>
Subject Re: querying time for Apache Phoenix
Date Wed, 27 Jul 2016 16:09:11 GMT
I believe what you're saying is correct, James. The SMALL hint is calling
scan.setSmall(true) on the scans for your query. There's some documentation
on this here: https://issues.apache.org/jira/browse/HBASE-9488, but I'm
having a hard time finding other documentation. Small scans prevent as many
RPCs as would otherwise occur when a scan is executed.

Thanks,
James

On Wed, Jul 27, 2016 at 8:12 AM, Heather, James (ELS) <
james.heather@elsevier.com> wrote:

> On Tue, 2016-07-26 at 08:39 -0700, James Taylor wrote:
>
> - if you're querying for a single row, use the serial and small hints like
> this: /*+ SERIAL SMALL */
>
>
> Quoting from the language reference:
>
> Generally, if the query is a point lookup or returns data that is likely
> in a single data block (64 KB by default), performance may improve when
> using this hint.
>
> Can you explain what's meant by "in a single data block"? Do you mean that
> the result is located on a single region server, and in a single HDFS block
> on that region server?
>
> In other words, if we're retrieving data from a single table, then it
> ought to be a small number of rows with fairly closely located primary keys?
>
> James
>
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