From: Jim C. Nasby <jim@nasby.net>
To: Bucky Jordan <bjordan@lumeta.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Brian Herlihy <btherl@yahoo.com.au>
Cc: Postgresql Performance <pgsql-performance@postgresql.org>
Subject: Collect stats during seqscan (was: Simple join optimized badly?)
Date: Wed, 11 Oct 2006 15:27:58 -0500
Message-ID: <20061011202758.GQ13487@nasby.net> (raw)
In-Reply-To: <78ED28FACE63744386D68D8A9D1CF5D4209C7A@MAIL.corp.lumeta.com>
References: <15661.1160534309@sss.pgh.pa.us>
<78ED28FACE63744386D68D8A9D1CF5D4209C7A@MAIL.corp.lumeta.com>
On Wed, Oct 11, 2006 at 10:27:26AM -0400, Bucky Jordan wrote:
> Also, I'm guessing this has already come up at some point, but what
> about allowing PG to do some stat collection during queries? If you're
> touching a lot of data (such as an import process) wouldn't it be more
> efficient (and perhaps more accurate) to collect stats then, rather than
> having to re-scan? It would be nice to be able to turn this on/off on a
> per query basis, seeing as it could have pretty negative impacts on OLTP
> performance...
I suspect that could be highly useful in data warehouse environments
where you're more likely to have to sequential scan a table. It would be
interesting to have it so that a sequential scan that will run to
completion also collects stats along the way.
--
Jim Nasby jim@nasby.net
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
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To: pgsql-performance@postgresql.org
Cc: jim@nasby.net, bjordan@lumeta.com, tgl@sss.pgh.pa.us, btherl@yahoo.com.au
Subject: Re: Collect stats during seqscan (was: Simple join optimized badly?)
In-Reply-To: <20061011202758.GQ13487@nasby.net>
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