Horton

Re: WAL Insertion Lock Improvements

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Nathan Bossart <nathandbossart@gmail.com>
Cc: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Andres Freund <andres@anarazel.de>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-05-09T03:32:07Z
Lists: pgsql-hackers 
On Mon, May 08, 2023 at 04:04:10PM -0700, Nathan Bossart wrote:
> On Mon, May 08, 2023 at 05:57:09PM +0530, Bharath Rupireddy wrote:
>> test-case 1: -T5, WAL ~16 bytes
>> test-case 1: -t1000, WAL ~16 bytes
> 
> I wonder if it's worth doing a couple of long-running tests, too.

Yes, 5s or 1000 transactions per client is too small, though it shows
that things are going in the right direction. 

(Will reply to the rest in a bit..)
--
Michael

Commits

  1. Optimize pg_atomic_exchange_u32 and pg_atomic_exchange_u64.

  2. Document more assumptions of LWLock variable changes with WAL inserts

  3. Optimize WAL insertion lock acquisition and release with some atomics

  4. Avoid the use of a separate spinlock to protect a LWLock's wait queue.