Horton

Re: pgsql_fdw, FDW for PostgreSQL server

Shigeru Hanada <shigeru.hanada@gmail.com>

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From: Shigeru Hanada <shigeru.hanada@gmail.com>
To: Marko Kreen <markokr@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Kohei KaiGai <kaigai@kaigai.gr.jp>, Tom Lane <tgl@sss.pgh.pa.us>, Albe Laurenz <laurenz.albe@wien.gv.at>, Hitoshi Harada <umi.tanuki@gmail.com>, Martijn van Oosterhout <kleptog@svana.org>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2012-02-08T12:24:40Z
Lists: pgsql-hackers 
(2012/02/02 18:24), Marko Kreen wrote:
> I think you want this instead:
> 
>    https://commitfest.postgresql.org/action/patch_view?id=769

With modified version of pgsql_fdw which uses row processor to retrieve
result tuples, I found significant performance gain on simple read-only
pgbench, though scale factor was very small (-s 3).  Executed command
was "pgbench -S -n -c 5 T 30".

Average tps (excluding connections establishing) of 3 times measurements
are:

pgsql_fdw with SQL-cursor    :  622
pgsql_fdw with Row Processor : 1219 - 2.0x faster than SQL-cursor
w/o pgsql_fdw(direct access) : 7719 - 6.3x faster than Row Processor

Row processor was almost 2x faster than SQL-cursor!  I'm looking forward
to this feature.

In addition to performance gain, of course memory usage was kept at very
low level. :)

Regards,
-- 
Shigeru Hanada