Re: gistchoose vs. bloat

Jeff Davis <pgsql@j-davis.com>

From: Jeff Davis <pgsql@j-davis.com>

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

Cc: Heikki Linnakangas <hlinnakangas@vmware.com>, Alexander Korotkov <aekorotkov@gmail.com>, Andres Freund <andres@2ndquadrant.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, pgsql-hackers@postgresql.org

Date: 2013-01-21T06:57:42Z

Lists: pgsql-hackers

On Mon, 2013-01-21 at 00:48 -0500, Tom Lane wrote:
> I looked at this patch.  ISTM we should not have the option at all but
> just do it always.  I cannot believe that always-go-left is ever a
> preferable strategy in the long run; the resulting imbalance in the
> index will surely kill any possible benefit.  Even if there are some
> cases where it miraculously fails to lose, how many users are going to
> realize that applies to their case and make use of the option?

Sounds good to me.

If I remember correctly, there was also an argument that it may be
useful for repeatable test results. That's a little questionable for
performance (except in those cases where few penalties are identical
anyway), but could plausibly be useful for a crash report or something.

Regards,
	Jeff Davis