Re: Improve LWLock tranche name visibility across backends

Nathan Bossart <nathandbossart@gmail.com>

From: Nathan Bossart <nathandbossart@gmail.com>

To: Andres Freund <andres@anarazel.de>

Cc: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, Sami Imseih <samimseih@gmail.com>, Rahila Syed <rahilasyed90@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2025-08-19T18:31:35Z

Lists: pgsql-hackers

On Tue, Aug 19, 2025 at 02:06:50PM -0400, Andres Freund wrote:
> Possibly stupid question - is it really worth having a dynamic structure here?
> The number of tranches is strictly bound, it seems like it'd be simpler to
> have an array of tranch nmes in shared memory.

Tranches can be allocated post-startup with LWLockNewTrancheId() (e.g.,
autoprewarm).

-- 
nathan

Commits

test_dsa: Avoid leaking LWLock tranches.
- c5c74282f2ea 19 (unreleased) landed
Teach DSM registry to ERROR if attaching to an uninitialized entry.
- b26d76f64327 18.2 landed
- ac2800ddc185 17.8 landed
- 1165a933aab1 19 (unreleased) landed
Add a test harness for the LWLock tranche code.
- 16607718c010 19 (unreleased) landed
Revert recent change to RequestNamedLWLockTranche().
- d814d7fc3d52 19 (unreleased) landed
Move dynamically-allocated LWLock tranche names to shared memory.
- 38b602b0289f 19 (unreleased) landed
Prepare DSM registry for upcoming changes to LWLock tranche names.
- 5487058b56e0 19 (unreleased) landed
Add GetNamedDSA() and GetNamedDSHash().
- fe07100e82b0 19 (unreleased) cited