Re: Introducing an advanced Frequent Update Optimization

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@crankycanuck.ca
In the future this spectacle of the middle classes shocking the avant-
garde will probably become the textbook definition of Postmodernism.                --Brad Holland