Re: gistchoose vs. bloat

Jeff Davis <pgsql(at)j-davis(dot)com> writes:
> 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.

Meh. There's already a random decision, in the equivalent place and for
a comparable reason, in btree (cf _bt_findinsertloc). Nobody's ever
complained about that being indeterminate, so I'm unconvinced that
there's a market for it with gist.

regards, tom lane