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Re: Much Ado About COUNT(*)

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Jim C(dot) Nasby" <decibel(at)decibel(dot)org>
Cc: Manfred Koizar <mkoi-pg(at)aon(dot)at>,Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>,"Jonah H(dot) Harris" <jharris(at)tvi(dot)edu>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Much Ado About COUNT(*)
Date: 2005-01-17 01:01:36
Message-ID: 20927.1105923696@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-announcepgsql-hackerspgsql-patches
"Jim C. Nasby" <decibel(at)decibel(dot)org> writes:
> Wouldn't the original proposal that had a state machine handle this?
> IIRC the original idea was:

> new tuple -> known good -> possibly dead -> known dead

Only if you disallow the transition from possibly dead back to known
good, which strikes me as a rather large disadvantage.  Failed UPDATEs
aren't so uncommon that it's okay to have one permanently disable the
optimization.

			regards, tom lane

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