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* Query Planner
@ 2007-02-26 11:49 Gauri Kanekar <meetgaurikanekar@gmail.com>
2007-02-26 11:52 ` Re: Query Planner Steinar H. Gunderson <sgunderson@bigfoot.com>
0 siblings, 1 reply; 2+ messages in thread
From: Gauri Kanekar @ 2007-02-26 11:49 UTC (permalink / raw)
To: pgsql-performance
Hi List,
I have a Query. So when i do explain analyse on it , it shows me many Hash
Joins.
So is it possible to indicate the Query Planner not to consider Hash Join.
--
Regards
Gauri
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: Query Planner
2007-02-26 11:49 Query Planner Gauri Kanekar <meetgaurikanekar@gmail.com>
@ 2007-02-26 11:52 ` Steinar H. Gunderson <sgunderson@bigfoot.com>
0 siblings, 0 replies; 2+ messages in thread
From: Steinar H. Gunderson @ 2007-02-26 11:52 UTC (permalink / raw)
To: Gauri Kanekar <meetgaurikanekar@gmail.com>; +Cc: pgsql-performance
On Mon, Feb 26, 2007 at 05:19:05PM +0530, Gauri Kanekar wrote:
> I have a Query. So when i do explain analyse on it , it shows me many Hash
> Joins.
> So is it possible to indicate the Query Planner not to consider Hash Join.
set enable_hashjoin = false;
This is very often the wrong solution, though. If hash join is indeed slower
than merge join, the planner should have guessed so, and it would be better
to find out why the planner guessed wrong, and correct it somehow.
/* Steinar */
--
Homepage: http://www.sesse.net/
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2007-02-26 11:49 Query Planner Gauri Kanekar <meetgaurikanekar@gmail.com>
2007-02-26 11:52 ` Steinar H. Gunderson <sgunderson@bigfoot.com>
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