From: | Andrew Sullivan <ajs(at)crankycanuck(dot)ca> |
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To: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Introducing an advanced Frequent Update Optimization |
Date: | 2006-11-09 09:09:38 |
Message-ID: | 20061109090938.GC17047@phlogiston.dyndns.org |
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Lists: | pgsql-hackers |
On Mon, Nov 06, 2006 at 09:50:53PM +0000, Simon Riggs wrote:
> - There are specific issues with the optimizer's ability to understand
> dead row numbers, which can in some cases lead to SeqScan plans that are
> inappropriate when tables grow because of updates. This is a red-herring
> that can lead to people thinking the situation is worse than it is; that
> needs fixing, but the core issues mentioned above remain.
I don't disagree with much of what you say, but I'm slightly
concerned about the wave-away answer that you give here. In my
experience on high-update tables -- especially ones with the ones
with few rows, but lots of open transactions over the lifetime of the
row -- accurate understanding of dead rows would be a _dramatic_
improvement (perhaps at least as significant as the improvement being
discussed).
That said, I'm not opposed to the line you're taking. I just don't
want this problem to sink forever, because it's a big problem.
A
--
Andrew Sullivan | ajs(at)crankycanuck(dot)ca
In the future this spectacle of the middle classes shocking the avant-
garde will probably become the textbook definition of Postmodernism.
--Brad Holland
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