Re: Improve LWLock tranche name visibility across backends

Hi,

On Fri, Aug 01, 2025 at 01:15:24PM -0500, Sami Imseih wrote:
> I think we could add a local backend copy that stays up to date with the
> DSA. One idea would be to use an atomic counter to track the number of
> entries in the DSA and compare it with a local backend counter whenever the
> tranche name lookup occurs. If the atomic counter is higher (since we
> don't have deletions),
> we can update the local copy. Updating the local table should be a
> rare occurrence, but it would
> require an additional atomic fetch every time the name lookup occurs, in all the
> above code paths.
>
> Perhaps there's a better approach?

I was thinking to switch to the DSA (and update local copy) when a name is
not found in the local copy. That way there is no need to maintain a counter and
the DSA overhead should be rare enough.

Regards,

--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com