Date: Tue, 18 Apr 2006 15:01:15 -0500
From: "Jim C. Nasby" <jnasby@pervasive.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Postgresql Performance <pgsql-performance@postgresql.org>
Subject: Re: Blocks read for index scans
Message-ID: <20060418200115.GF49405@pervasive.com>
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	<20060414061414.GY49405@pervasive.com>
	<9369.1145027575@sss.pgh.pa.us>
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On Fri, Apr 14, 2006 at 11:12:55AM -0400, Tom Lane wrote:
> "Jim C. Nasby" <jnasby@pervasive.com> writes:
> > In my case it would be helpful to break the heap access numbers out
> > between seqscans and index scans, since each of those represents very
> > different access patterns. Would adding that be a mess?
> 
> Yes; it'd require more counters-per-table than we now keep, thus
> nontrivial bloat in the stats collector's tables.  Not to mention

ISTM it would only require two additional columns, which doesn't seem
unreasonable, especially considering the value of the information
collected.

> incompatible changes in the pgstats views and the underlying functions
> (which some apps probably use directly).

There's certainly ways around that issue, especially since this would
only be adding new information (though we would probably want to
consider the old info as depricated and eventually remove it).
-- 
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461