Horton

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

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Andres Freund <andres@anarazel.de>, pgsql-hackers@postgresql.org, Robert Haas <robertmhaas@gmail.com>, Melanie Plageman <melanieplageman@gmail.com>, David Rowley <dgrowleyml@gmail.com>
Date: 2023-01-11T21:18:34Z
Lists: pgsql-hackers 
Peter Geoghegan <pg@bowt.ie> writes:
> On Wed, Jan 11, 2023 at 11:18 AM Andres Freund <andres@anarazel.de> wrote:
>> I don't like that - it's also quite useful to disable use of ringbuffers when
>> you actually need to clean up indexes. Especially when we have a lot of dead
>> tuples we'll rescan indexes over and over...

> That's a fair point.

> My vote goes to "REUSE_BUFFERS", then.

I wonder whether it could make sense to allow a larger ringbuffer size,
rather than just the limit cases of "on" and "off".

			regards, tom lane

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