Re: Yet another fast GiST build (typo)

From: "Andrey M(dot) Borodin" <x4mmm(at)yandex-team(dot)ru>
To: Heikki Linnakangas <hlinnaka(at)iki(dot)fi>
Cc: Pavel Borisov <pashkin(dot)elfe(at)gmail(dot)com>, Thomas Munro <thomas(dot)munro(at)gmail(dot)com>, Daniel Gustafsson <daniel(at)yesql(dot)se>, Erik Rijkers <er(at)xs4all(dot)nl>, Michael Paquier <michael(at)paquier(dot)xyz>, Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru>, Darafei Komяpa Praliaskouski <me(at)komzpa(dot)net>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Yet another fast GiST build (typo)
Date: 2020-09-07 07:14:35
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> 6 сент. 2020 г., в 18:26, Heikki Linnakangas <hlinnaka(at)iki(dot)fi> написал(а):
> On 05/09/2020 14:53, Andrey M. Borodin wrote:
>> Thanks for ideas, Heikki. Please see v13 with proposed changes.
> Thanks, that was quick!
>> But I've found out that logging page-by-page slows down GiST build by
>> approximately 15% (when CPU constrained). Though In think that this
>> is IO-wise.
> Hmm, any ideas why that is? log_newpage_range() writes one WAL record for 32 pages, while now you're writing one record per page, so you'll have a little bit more overhead from that. But 15% seems like a lot.

Hmm, this works for B-tree too.
this index creation
psql -c '\timing' -c "create table x as select random() from generate_series(1,10000000,1);" -c "create index ON x (random );"
takes 7 seconds on may machine, but with one weird patch it takes only 6 :)

Maybe I'm missing something? Like forgot to log 10% of pages, or something like that...

Best regards, Andrey Borodin.

Attachment Content-Type Size
0001-nbtree-faster-logging.patch application/octet-stream 2.1 KB

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