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In-Reply-To: <4AF81207.4050008@shopzeus.com>
References: <4AF81207.4050008@shopzeus.com>
Date: Mon, 9 Nov 2009 08:48:55 -0500
Message-ID: <603c8f070911090548g40d42a1erdbe262c545612739@mail.gmail.com>
Subject: Re: random_page_cost for tablespace
From: Robert Haas <robertmhaas@gmail.com>
To: Laszlo Nagy <gandalf@shopzeus.com>
Cc: pgsql-performance <pgsql-performance@postgresql.org>
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2009/11/9 Laszlo Nagy <gandalf@shopzeus.com>:
> We have a bigger table with some million rows. Number of index scans is
> high, number of seq reads is low. This table if often joined with
> others... so we want to buy a new SSD drive, create a tablespace on it
> and put this big table on it. Random read speed on SSD is identical to
> seq read. However, I need to tell the optimizer that random_page_cost is
> less for the new tablespace. Is there a way to do it?

I happen to be working on a patch for this exact feature.  However,
even assuming it gets in, that means waiting for 8.5.

...Robert