Horton

Re: Yet another fast GiST build

Alexander Korotkov <a.korotkov@postgrespro.ru>

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From: Alexander Korotkov <a.korotkov@postgrespro.ru>
To: Andrey Borodin <x4mmm@yandex-team.ru>
Cc: Darafei Komяpa Praliaskouski <me@komzpa.net>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2019-09-01T17:17:48Z
Lists: pgsql-hackers 
On Fri, Aug 30, 2019 at 2:44 PM Andrey Borodin <x4mmm@yandex-team.ru> wrote:
>
> 30 авг. 2019 г., в 3:47, Alexander Korotkov <a.korotkov@postgrespro.ru> написал(а):
>
> 1) Binary search in non-leaf pages instead of probing each key is much faster.
>
>
> That's a neat idea, but key union breaks ordering, even for z-order.
> for two sets of tuples X and Y
> if for any i,o from N, Xi < Yo
> does not guaranty union(X) < union (Y)
>
> For example consider this z-ordered keyspace (picture attached)
>
> union(5, 9) is z-order-smaller than union(4,4)
>
> I'm not even sure we can use sorted search for choosing subtree for insertion.


Sorry, I didn't explain my proposal in enough details.  I didn't mean
B-tree separator keys would be the same as union key (MBR).  I mean
B-tree on Z-values, which maintains union key in addition to separator
keys.  So, you select downlink to insert using separator Z-values and
then also extend union key (if needed).  It's probably still not
enough detail yet.  I'll try to spend more time for more detailed
description later.

>
> How do you think, should I supply GiST-build patch with docs and tests and add it to CF? Or do we need more design discussion before?


+1 for adding to CF.

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company

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.