Re: Improve LWLock tranche name visibility across backends

> > On Mon, Aug 25, 2025 at 04:59:41PM -0500, Sami Imseih wrote:
> > > hmm, can we really avoid a shared lock when reading from shared memory?
> > > considering access for both reads and writes can be concurrent to shared
> > > memory. We are also taking an exclusive lock when writing a new tranche.
> >
> > We probably want to hold a lock while we 1) increment LWLockCounter and
> > copy a new tranche name to memory and
>
> In the last rev, I removed the spinlock acquired on ShmemLock in-lieu of
> a LWLock. This is because I wanted a single LWLock acquisition while
> both incrementing LWLockCounter and writing to shared memory, and
> doing this much work, particularly writing to shared memory,
> with a spinlock seemed inappropriate. With that said, this is not high
> concurrency of performance sensitive activity at all, so perhaps I was
> being overly paranoid.

Here is v12 that replaces the LWLock to access the shared memory with a
ShmemLock and implements a local counter.

--
Sami