Horton

Re: [HACKERS] Vacuum: allow usage of more than 1GB of work mem

Claudio Freire <klaussfreire@gmail.com>

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From: Claudio Freire <klaussfreire@gmail.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>, Thomas Munro <thomas.munro@enterprisedb.com>, Stephen Frost <sfrost@snowman.net>, Michael Paquier <michael.paquier@gmail.com>, Daniel Gustafsson <daniel@yesql.se>, Andres Freund <andres@anarazel.de>, Masahiko Sawada <sawada.mshk@gmail.com>, Anastasia Lubennikova <a.lubennikova@postgrespro.ru>, Anastasia Lubennikova <lubennikovaav@gmail.com>, PostgreSQL-Dev <pgsql-hackers@postgresql.org>
Date: 2018-03-16T21:46:06Z
Lists: pgsql-hackers

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On Fri, Feb 9, 2018 at 1:05 PM, Claudio Freire <klaussfreire@gmail.com> wrote:
> Turns out that it was a tad oversized. 300k tuples seems enough.
>
> Attached is a new patch version that:
>
> - Uses an unlogged table to make the large mwm test faster
> - Uses a wait_barrier helper that waits for concurrent transactions
>   to finish before vacuuming tables, to make sure deleted tuples
>   actually are vacuumable
> - Tweaks the size of the large mwm test to be as small as possible
> - Optimizes the delete to avoid expensive operations yet attain
>   the same end result

Attached rebased versions of the patches (they weren't applying to
current master)

Commits

  1. Prefetch blocks during lazy vacuum's truncation scan

  2. Explain unaccounted for space in pgstattuple.