Horton

Re: Much Ado About COUNT(*)

Tom Lane <tgl@sss.pgh.pa.us>

View thread
From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Jim C. Nasby" <decibel@decibel.org>
Cc: Manfred Koizar <mkoi-pg@aon.at>, Bruce Momjian <pgman@candle.pha.pa.us>, "Jonah H. Harris" <jharris@tvi.edu>, pgsql-hackers@postgresql.org
Date: 2005-01-17T01:01:36Z
Lists: pgsql-hackers 
"Jim C. Nasby" <decibel@decibel.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