Re: Red-black tree for GIN

From: Oleg Bartunov <oleg(at)sai(dot)msu(dot)su>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Teodor Sigaev <teodor(at)sigaev(dot)ru>, Pgsql Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Red-black tree for GIN
Date: 2010-01-11 06:49:12
Message-ID: Pine.LNX.4.64.1001110945570.10030@sn.sai.msu.ru
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Robert,

we have benchmark for rbtree
http://www.sai.msu.su/~megera/wiki/2009-07-27
rbtree, actually, fix corner cases with ordered input, with little
overhead.

As you may see from knngist patch, rbtree used in gist code, so, please,
leave rbtree code as is.

Oleg
On Sun, 10 Jan 2010, Robert Haas wrote:

> On Thu, Dec 31, 2009 at 4:19 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> > My other question is as related to performance. =A0Can you provide a
> > test case that shows the performance improvement with this patch?
>
> So, we still don't have a test case for this patch. During the
> November CommitFest, Greg Smith griped a bit about the lack of a
> reproducible performance benchmark for the XLogInsert patch:
>
> http://archives.postgresql.org/pgsql-hackers/2009-12/msg00816.php
>
> ...and I would say the same logic applies to this patch, maybe even
> moreso. Tom has already applied a partial workaround for this
> problem, and I'm feeling like it won't be trivial to figure out what
> to measure to see the remaining issue and measure how much this new
> implementation helps.
>
> The coding pattern that this patch uses also merits some discussion.
> Basically, rbtree.c is a generic implementation of red-black trees -
> from a textbook - which ginbulk.c then uses for GIN. One possible
> advantage of this implementation is that it might make it possible for
> us to use the rbtree.c logic in other places, if we have other data
> structures that need similar treatment. But I'm not sure if that's
> the way we want to go. The other alternative is to drop the
> generalized implementation and incorporate the logic directly into
> ginbulk.c. I really don't know which is better, but I'd like to hear
> some other opinions...
>
> ...Robert
>
> --=20
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Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru)
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83

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