Horton

Re: Yet another fast GiST build

Peter Eisentraut <peter.eisentraut@enterprisedb.com>

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From: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
To: Heikki Linnakangas <hlinnaka@iki.fi>, Andrey Borodin <x4mmm@yandex-team.ru>, Peter Geoghegan <pg@bowt.ie>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Justin Pryzby <pryzby@telsasoft.com>, 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>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2021-01-15T05:24:42Z
Lists: pgsql-hackers 
On 2021-01-12 14:49, Heikki Linnakangas wrote:
>>>> I suggest calling BuildIndexValueDescription() from your own custom
>>>> debug instrumentation code.
>>> Thanks for the hint, Peter!
>>> This function does exactly what I want to do. But I have no Relation inside gist_page_items(bytea) function... probably, I'll add gist_page_items(relname, blockno) overload to fetch keys.
>>
>> PFA patch with implementation.
> 
> I did a bit of cleanup on the function signature. The .sql script
> claimed that gist_page_items() took bytea as argument, but in reality it
> was a relation name, as text. I changed it so that it takes a page image
> as argument, instead of reading the block straight from the index.
> Mainly to make it consistent with brin_page_items(), if it wasn't for
> that precedence I might've gone either way on it.

I noticed this patch while working on another patch for pageinspect [0], 
and this one appears to introduce a problem similar to the one the other 
patch attempts to fix: The "itemlen" output parameters are declared to 
be of type smallint, but the underlying C data is of type uint16 
(OffsetNumber).  I don't know the details of gist enough to determine 
whether overflow is possible here.  If not, perhaps a check or at least 
a comment would be useful.  Otherwise, these parameters should be of 
type int in SQL.

[0]: 
https://www.postgresql.org/message-id/09e2dd82-4eb6-bba1-271a-d2b58bf6c71f@enterprisedb.com

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.