Horton

Re: Yet another fast GiST build

Tom Lane <tgl@sss.pgh.pa.us>

View thread View on postgr.es
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, "Andrey M. Borodin" <x4mmm@yandex-team.ru>, 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@postgresql.org
Date: 2020-09-20T23:06:09Z
Lists: pgsql-hackers 
Justin Pryzby <pryzby@telsasoft.com> writes:
> This also appears to break checksums.

I was wondering about that, because the typical pattern for use of
smgrextend for indexes seems to be

	RelationOpenSmgr(rel);
	PageSetChecksumInplace(page, lastblock);
	smgrextend(rel->rd_smgr, MAIN_FORKNUM, lastblock, zerobuf.data, false);

and gist_indexsortbuild wasn't doing either of the first two things.

gist_indexsortbuild_flush_ready_pages looks like it might be
a few bricks shy of a load too.  But my local CLOBBER_CACHE_ALWAYS
run hasn't gotten to anything except the pretty-trivial index
made in point.sql, so I don't have evidence about it.

Another interesting point is that all the other index AMs seem to WAL-log
the new page before the smgrextend call, whereas this code is doing it
in the other order.  I strongly doubt that both patterns are equally
correct.  Could be that the other AMs are in the wrong though.

			regards, tom lane

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.