Horton

Re: Yet another fast GiST build

x4mmm@yandex-team.ru

View thread View on postgr.es
From: Andrey Borodin <x4mmm@yandex-team.ru>
To: Alexander Korotkov <a.korotkov@postgrespro.ru>
Cc: Darafei Komяpa Praliaskouski <me@komzpa.net>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2019-08-30T11:44:43Z
Lists: pgsql-hackers 

> 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.

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?


Best regards, Andrey Borodin.

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.