Re: Much Ado About COUNT(*)

On Sun, Jan 16, 2005 at 08:01:36PM -0500, Tom Lane wrote:
> "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.

Actually, I guess I wasn't understanding the problem to begin with.
You'd never go from new tuple to known good while the transaction that
created the tuple was in-flight, right? If that's the case, I'm not sure
where there's a race condition. You can't delete a tuple that hasn't
been committed, right?
-- 
Jim C. Nasby, Database Consultant               decibel@decibel.org 
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