Horton

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

David Rowley <dgrowleyml@gmail.com>

View thread View on postgr.es
From: David Rowley <dgrowleyml@gmail.com>
To: David Rowley <dgrowleyml@gmail.com>, Andres Freund <andres@anarazel.de>, Justin Pryzby <pryzby@telsasoft.com>, Masahiko Sawada <sawada.mshk@gmail.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>
Date: 2023-04-07T00:52:03Z
Lists: pgsql-hackers 
On Fri, 7 Apr 2023 at 09:44, Melanie Plageman <melanieplageman@gmail.com> wrote:
> Otherwise, LGTM.

Thanks for looking.  I've also taken Justin's comments about the
README into account and fixed that part.

I've pushed the patch after a little more adjusting.  I added some
text to the docs that mention larger VACUUM_BUFFER_LIMITs can speed up
vacuum and also a reason why they might not want to go nuts with it.

I've also just now pushed the vacuumdb patch too. I ended up adjusting
some of the ERROR messages in the main patch after the following not
so nice user experience:

$ vacuumdb --buffer-usage-limit=1TB --analyze postgres
vacuumdb: vacuuming database "postgres"
SQL: VACUUM (SKIP_DATABASE_STATS, ANALYZE, BUFFER_USAGE_LIMIT '1TB')
vacuumdb: error: processing of database "postgres" failed: ERROR:
buffer_usage_limit option must be 0 or between 128 KB and 16777216 KB

$ vacuumdb --buffer-usage-limit=128KB --analyze postgres
vacuumdb: vacuuming database "postgres"
SQL: VACUUM (SKIP_DATABASE_STATS, ANALYZE, BUFFER_USAGE_LIMIT '128KB')
vacuumdb: error: processing of database "postgres" failed: ERROR:
value: "128KB": is invalid for buffer_usage_limit
HINT:  Valid units for this parameter are "B", "kB", "MB", "GB", and "TB".

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