From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jim Nasby <jnasby@pervasive.com>
Cc: Postgresql Performance <pgsql-performance@postgresql.org>
Subject: Re: Blocks read for index scans
Date: Thu, 13 Apr 2006 20:36:09 -0400
Message-ID: <2789.1144974969@sss.pgh.pa.us> (raw)
In-Reply-To: <85979594-1CCA-43C5-A8F2-08685CF41ACE@pervasive.com>
References: <85979594-1CCA-43C5-A8F2-08685CF41ACE@pervasive.com>
Jim Nasby <jnasby@pervasive.com> writes:
> While working on determining a good stripe size for a database, I
> realized it would be handy to know what the average request size is.
> Getting this info is a simple matter of joining pg_stat_all_tables
> and pg_statio_all_tables and doing some math, but there's one issue
> I've found; it appears that there's no information on how many heap
> blocks were read in by an index scan. Is there any way to get that info?
If the table is otherwise idle, the change in the table's entry in
pgstatio_all_tables should do, no?
(This is as of 8.1 ... older versions acted a bit differently IIRC.)
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, jnasby@pervasive.com
Subject: Re: Blocks read for index scans
In-Reply-To: <2789.1144974969@sss.pgh.pa.us>
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