Horton

Re: Yet another fast GiST build

Heikki Linnakangas <hlinnaka@iki.fi>

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From: Heikki Linnakangas <hlinnaka@iki.fi>
To: "Andrey M. Borodin" <x4mmm@yandex-team.ru>
Cc: Darafei Komяpa Praliaskouski <me@komzpa.net>, Pavel Borisov <pashkin.elfe@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, Michael Paquier <michael@paquier.xyz>, Alexander Korotkov <a.korotkov@postgrespro.ru>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2020-09-10T12:43:11Z
Lists: pgsql-hackers

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On 09/09/2020 19:50, Andrey M. Borodin wrote:
>> 9 сент. 2020 г., в 20:39, Heikki Linnakangas <hlinnaka@iki.fi> написал(а):
>>
>> On 09/09/2020 15:20, Darafei "Komяpa" Praliaskouski wrote:
>>> On Wed, Sep 9, 2020 at 3:09 PM Heikki Linnakangas <hlinnaka@iki.fi> wrote:
>>>> Come to think of it, the point z-order comparator could benefit a lot
>>>> from key abbreviation, too. You could do the point -> zorder conversion
>>>> in the abbreviation routine.
>>> That's how it works in PostGIS, only that we moved to more
>>> effecient Hilbert curve:
>>> https://github.com/postgis/postgis/blob/54399b9f6b0f02e8db9444f9f042b8d4ca6d4fa4/postgis/lwgeom_btree.c#L171
>>
>> Thanks, that's interesting.
>>
>> I implemented the abbreviated keys for the point opclass, too, and noticed that the patch as it was never used it. I reworked the patch so that tuplesort_begin_index_gist() is responsible for looking up the sortsupport function, like tuplesort_begin_index_btree() does, and uses abbreviation when possible.
> Wow, abbreviated sort made gist for points construction even 1.5x faster!
> btw there is small typo in arg names in gist_bbox_zorder_cmp_abbrev(); z1,z2 -> a,b

One more patch version attached. I fixed some memory leaks, and fixed 
the abbreviation on 32-bit systems, and a bunch of small comment changes 
and such.

- Heikki

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.