Horton

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

Masahiko Sawada <sawada.mshk@gmail.com>

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From: Masahiko Sawada <sawada.mshk@gmail.com>
To: David Rowley <dgrowleyml@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>, pgsql-hackers@postgresql.org, Robert Haas <robertmhaas@gmail.com>, Melanie Plageman <melanieplageman@gmail.com>
Date: 2023-04-26T08:47:43Z
Lists: pgsql-hackers

Attachments

Hi,

On Sun, Apr 16, 2023 at 9:09 AM David Rowley <dgrowleyml@gmail.com> wrote:
>
> On Sat, 15 Apr 2023 at 12:59, David Rowley <dgrowleyml@gmail.com> wrote:
> > These are all valid points. I've attached a patch aiming to address
> > each of them.
>
> I tweaked this a little further and pushed it.
>

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.

Regards,

-- 
Masahiko Sawada
Amazon Web Services: https://aws.amazon.com

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