From: Tom Lane <tgl@sss.pgh.pa.us>
To: stefan@konink.de
cc: pgsql-bugs@postgresql.org
Subject: Re: BUG #8130: Hashjoin still gives issues
In-reply-to: <E1UXWS7-0007V8-N2@wrigleys.postgresql.org>
References: <E1UXWS7-0007V8-N2@wrigleys.postgresql.org>
Comments: In-reply-to stefan@konink.de
	message dated "Wed, 01 May 2013 12:48:07 -0000"
Date: Wed, 01 May 2013 11:10:52 -0400
Message-ID: <3469.1367421052@sss.pgh.pa.us>
Precedence: bulk
Sender: pgsql-bugs-owner@postgresql.org

stefan@konink.de writes:
> By setting "set enable_hashjoin = off;" performance in our entire
> application increased 30 fold in throughput, which was a bit unexpected but
> highly appreciated. The result of the last query:

At least in this example, the query appears to be fully cached and so
you would need a random_page_cost near 1 to reflect the system's
behavior properly.  If your DB fits mostly in RAM, adjusting the cost
parameters is a much better idea than fooling with the enable_
parameters.

> What can we do to provide a bit more of information?

https://wiki.postgresql.org/wiki/Slow_Query_Questions

There is no particularly good reason to think this is a bug; please
take it up on pgsql-performance if you have more questions.

			regards, tom lane


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