Horton

Re: Yet another fast GiST build

Pavel Borisov <pashkin.elfe@gmail.com>

View thread View on postgr.es
From: Pavel Borisov <pashkin.elfe@gmail.com>
To: "Andrey M. Borodin" <x4mmm@yandex-team.ru>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Thomas Munro <thomas.munro@gmail.com>, Michael Paquier <michael@paquier.xyz>, Alexander Korotkov <a.korotkov@postgrespro.ru>, Darafei Komяpa Praliaskouski <me@komzpa.net>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2020-09-08T18:33:59Z
Lists: pgsql-hackers 
>
> > Thanks! Did you measure the quality of the built index somehow? The
> > ordering shouldn't make any difference to the build speed, but it
> > affects the shape of the resulting index and the speed of queries
> > against it.


Again I've tried random select tests near axes and haven't noticed any
performance difference between ordinary gist build and z-ordered one. The
same is for selects far from axes. Theoretically, there may be a possible
slowdown for particular points inside the MBR which crosses the axis but I
haven't tried to dig so deep and haven't tested performance as a function
of coordinate.

So I feel this patch is not about select speed optimization.

-- 
Best regards,
Pavel Borisov

Postgres Professional: http://postgrespro.com <http://www.postgrespro.com>

Commits

  1. Add sortsupport for gist_btree opclasses, for faster index builds.

  2. pageinspect: Fix relcache leak in gist_page_items().

  3. Fix test failure with wal_level=minimal.

  4. Enhance nbtree index tuple deletion.

  5. Fix portability issues in the new gist pageinspect test.

  6. Add functions to 'pageinspect' to inspect GiST indexes.

  7. Fix missing validation for the new GiST sortsupport functions.

  8. Fix compilation warning in xlog.c

  9. Set right-links during sorted GiST index build.

  10. Fix checksum calculation in the new sorting GiST build.

  11. Add support for building GiST index by sorting.