Re: Improve LWLock tranche name visibility across backends

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

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

To: Nathan Bossart <nathandbossart@gmail.com>

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

Date: 2025-07-14T19:55:32Z

Lists: pgsql-hackers

Nathan Bossart <nathandbossart@gmail.com> writes:
> Ah, I missed the problem with postmaster.  Could we have the first backend
> that needs to access the table be responsible for creating it and
> populating it with the built-in/requested-at-startup entries?  Also, is
> there any chance that postmaster might need to access the tranche names?

Seems quite hazardous to let the postmaster get involved with such
a data structure.  If it seems to need to, we'd better rethink
where to put the functionality that needs the access.

			regards, tom lane

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