Horton

Re: Yet another fast GiST build

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Alexander Korotkov <a.korotkov@postgrespro.ru>
Cc: Andrey Borodin <x4mmm@yandex-team.ru>, Darafei Komяpa Praliaskouski <me@komzpa.net>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2019-08-29T23:33:48Z
Lists: pgsql-hackers 
On Thu, Aug 29, 2019 at 3:48 PM Alexander Korotkov
<a.korotkov@postgrespro.ru> wrote:
> > As you can see, Z-order build is on order of magnitude faster. Select performance is roughly the same. Also, index is significantly smaller.
>
> Cool!  These experiments bring me to following thoughts.  Can we not
> only build, but also maintain GiST indexes in B-tree-like manner?  If
> we put Z-value together with MBR to the non-leaf keys, that should be
> possible.  Maintaining it in B-tree-like manner would have a lot of
> advantages.

I'm not an expert on GiST, but that seems like it would have a lot of
advantages in the long term. It is certainly theoretically appealing.

Could this make it easier to use merge join with containment
operators? I'm thinking of things like geospatial joins, which can
generally only be performed as nested loop joins at the moment. This
is often wildly inefficient.

-- 
Peter Geoghegan

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.