Re: Faster Updates

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: PFC <lists(at)peufeu(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Faster Updates
Date: 2006-06-03 15:27:03
Message-ID: 16058.1149348423@sss.pgh.pa.us
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PFC <lists(at)peufeu(dot)com> writes:
> What do you think ?

Sounds enormously complicated and of very doubtful net win --- you're
moving a lot of overhead into SELECT in order to make UPDATE cheaper,
and on top of that the restriction to same-page will limit the
usefulness quite a lot (unless we deliberately keep pages less than
full, which costs a lot in distributed extra I/O).

Basically this is an extension of the notion of update tuple chains.
Anyone who's been around the project awhile will know that we've had
an unreasonably large number of corner-case bugs associated with tuple
chains (particularly in VACUUM FULL), so adding a second level of
complexity to 'em doesn't sound very appealing to me.

regards, tom lane

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