From: Mark Kirkwood <markir@paradise.net.nz>
To: Luke Lonergan <llonergan@greenplum.com>
Cc: stange@rentec.com, Greg Stark <gsstark@mit.edu>
Cc: Dave Cramer <pg@fastcrypt.com>
Cc: Joshua Marsh <icub3d@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Hardware/OS recommendations for large databases (
Date: Thu, 24 Nov 2005 22:11:36 +1300
Message-ID: <438583C8.4050809@paradise.net.nz> (raw)
In-Reply-To: <BFAAB702.1460D%llonergan@greenplum.com>
References: <BFAAB702.1460D%llonergan@greenplum.com>
Luke Lonergan wrote:
> Mark,
>
>
> It would be nice to put some tracers into the executor and see where the
> time is going. I'm also curious about the impact of the new 8.1 virtual
> tuples in reducing the executor overhead. In this case my bet's on the agg
> node itself, what do you think?
>
Yeah - it's pretty clear that the count aggregate is fairly expensive
wrt cpu - However, I am not sure if all agg nodes suffer this way (guess
we could try a trivial aggregate that does nothing for all tuples bar
the last and just reports the final value it sees).
Cheers
Mark
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Cc: markir@paradise.net.nz, llonergan@greenplum.com, gsstark@mit.edu, pg@fastcrypt.com, icub3d@gmail.com
Subject: Re: Hardware/OS recommendations for large databases (
In-Reply-To: <438583C8.4050809@paradise.net.nz>
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