Re: LogwrtResult contended spinlock

Jeff Davis <pgsql@j-davis.com>

From: Jeff Davis <pgsql@j-davis.com>

To: Alvaro Herrera <alvherre@alvh.no-ip.org>, Tom Lane <tgl@sss.pgh.pa.us>

Cc: Andres Freund <andres@anarazel.de>, pgsql-hackers@lists.postgresql.org, Jaime Casanova <jcasanov@systemguards.com.ec>

Date: 2024-02-13T01:44:33Z

Lists: pgsql-hackers

On Fri, 2022-09-23 at 10:49 +0200, Alvaro Herrera wrote:
> On 2022-Jul-28, Alvaro Herrera wrote:
> 
> > v10 is just a trivial rebase.  No changes.  Moved to next
> > commitfest.
> 
> I realized that because of commit e369f3708636 this change is no
> longer
> as critical as it used to be, so I'm withdrawing this patch from the
> commitfest.

It looks like there's some renewed interest in this patch:

https://www.postgresql.org/message-id/20240213001150.4uqzh7tinuhvoopl@awork3.anarazel.de

even if there's not a pressing performance conern now, it could clean
up the complexity of having a non-shared copy of LogwrtResult.

Regards,
	Jeff Davis

Commits

Remove bogus assertion in pg_atomic_monotonic_advance_u64
- 768f0c3e21b3 18.0 landed
- 3a9d0d774d90 17.0 landed
Add XLogCtl->logInsertResult
- f3ff7bf83bce 17.0 cited
Operate XLogCtl->log{Write,Flush}Result with atomics
- ee1cbe806dad 17.0 landed
Split XLogCtl->LogwrtResult into separate struct members
- c9920a9068ea 17.0 landed
Introduce atomic read/write functions with full barrier semantics.
- bd5132db558b 17.0 cited
Reduce the number of GetFlushRecPtr() calls done by walsenders.
- e369f3708636 13.0 cited
Remove most volatile qualifiers from xlog.c
- 6ba4ecbf477e 9.5.0 cited