Horton

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

Ants Aasma <ants@cybertec.at>

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From: Ants Aasma <ants@cybertec.at>
To: Melanie Plageman <melanieplageman@gmail.com>
Cc: Justin Pryzby <pryzby@telsasoft.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>, Peter Geoghegan <pg@bowt.ie>, pgsql-hackers@postgresql.org, Robert Haas <robertmhaas@gmail.com>, David Rowley <dgrowleyml@gmail.com>
Date: 2023-03-15T10:48:22Z
Lists: pgsql-hackers 
On Wed, 15 Mar 2023 at 02:57, Melanie Plageman
<melanieplageman@gmail.com> wrote:
> > > Subject: [PATCH v3 3/3] add vacuum option to specify ring_size and guc
> >
> > >  #define INT_ACCESS_ONCE(var) ((int)(*((volatile int *)&(var))))
> > > +#define bufsize_limit_to_nbuffers(bufsize) (bufsize * 1024 / BLCKSZ)
> >
> > Macros are normally be capitalized
>
> Yes, there doesn't seem to be a great amount of consistency around
> this... See pgstat.c read_chunk_s and bufmgr.c BufHdrGetBlock and
> friends. Though there are probably more capitalized than not. Since it
> does a bit of math and returns a value, I wanted to convey that it was
> more like a function. Also, since the name was long, I thought all-caps
> would be hard to read. However, if you or others feel strongly, I am
> attached neither to the capitalization nor to the name at all (what do
> you think of the name?).

A static inline function seems like a less surprising and more type
safe solution for this.

-- 
Ants Aasma
Senior Database Engineer
www.cybertec-postgresql.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