Re: Performance improvement for joins where outer side is unique

From: David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>
To: Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>
Cc: Simon Riggs <simon(at)2ndquadrant(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Performance improvement for joins where outer side is unique
Date: 2016-01-22 20:42:40
Message-ID: CAKJS1f_30MyRMK70GO1FHXXhE7em8sAufs8i=VVdqr6utN7W6Q@mail.gmail.com
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On 23 January 2016 at 05:36, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
> OK. I've looked at the patch again today, and it seems broken bv 45be99f8 as
> the partial paths were not passing the unique_inner to the create_*_path()
> functions. The attached patch should fix that.
>

Thanks for looking at this again, and thanks for fixing that problem.

I've attached an updated patch which incorporates your change, and
also another 2 small tweaks that I made after making another pass over
this myself.

> Otherwise I think the patch is ready for committer - I think this is a
> valuable optimization and I see nothing wrong with the code.
>
>
> Any objections to marking it accordingly?

None from me. I think it's had plenty of review time over the last year.

The only other thing I can possibly think of is to apply most of the
analyzejoins.c changes as a refactor patch first. If committer wants
that, I can separate these out, but I'll hold off for a response
before doing that.

--
David Rowley http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services

Attachment Content-Type Size
unique_joins_ba5b9cb_2016-01-23.patch application/octet-stream 76.6 KB

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