Horton

Re: Option to not use ringbuffer in VACUUM, using it in failsafe mode

David Rowley <dgrowleyml@gmail.com>

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From: David Rowley <dgrowleyml@gmail.com>
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: Peter Eisentraut <peter.eisentraut@enterprisedb.com>, Andres Freund <andres@anarazel.de>, Justin Pryzby <pryzby@telsasoft.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Peter Geoghegan <pg@bowt.ie>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Robert Haas <robertmhaas@gmail.com>, Melanie Plageman <melanieplageman@gmail.com>
Date: 2023-04-26T11:26:43Z
Lists: pgsql-hackers 
On Wed, 26 Apr 2023, 8:48 pm Masahiko Sawada, <sawada.mshk@gmail.com> wrote:

> I realized that the value of vacuum_buffer_usage_limit parameter in
> postgresql.conf.sample doesn't have the unit:
>
> #vacuum_buffer_usage_limit = 256 # size of vacuum and analyze buffer
> access strategy ring.
>                                  # 0 to disable vacuum buffer access
> strategy
>                                  # range 128kB to 16GB
>
> It works but I think we might want to add the unit kB for
> understandability and consistency with other GUC_UNIT_KB parameters.
> I've attached a small patch that adds the unit and aligns the indent
> of the comments to the perimeter parameters.
>

I'm not currently able to check, but if work_mem has a unit in the sample
conf then I agree that vacuum_buffer_usage_limit should too.

I'm fine for you to go ahead and adjust this, otherwise it'll be Monday
before I can.

David

>

Commits

  1. Add unit to vacuum_buffer_usage_limit value in postgresql.conf.sample.

  2. Improve VACUUM/ANALYZE BUFFER_USAGE_LIMIT docs

  3. Add --buffer-usage-limit option to vacuumdb

  4. Add VACUUM/ANALYZE BUFFER_USAGE_LIMIT option

  5. Move various prechecks from vacuum() into ExecVacuum()

  6. Always make a BufferAccessStrategy for ANALYZE

  7. Rename BufferAccessStrategyData.ring_size to nbuffers

  8. Disable vacuum's use of a buffer access strategy during failsafe

  9. Only make buffer strategy for vacuum when it's likely needed

  10. Remove some global variables from vacuum.c

  11. Doc: add Buffer Access Strategy to the glossary