Re: introduce dynamic shared memory registry

On Tue, Jan 2, 2024 at 11:21 AM Nathan Bossart <nathandbossart@gmail.com> wrote:
> > Are we expecting, for instance, a 128-bit UUID being used as a key and
> > hence limiting it to a higher value 256 instead of just NAMEDATALEN?
> > My thoughts were around saving a few bytes of shared memory space that
> > can get higher when multiple modules using a DSM registry with
> > multiple DSM segments.
>
> I'm not really expecting folks to use more than, say, 16 characters for the
> key, but I intentionally set it much higher in case someone did have a
> reason to use longer keys.  I'll lower it to 64 in the next revision unless
> anyone else objects.

This surely doesn't matter either way. We're not expecting this hash
table to have more than a handful of entries; the difference between
256, 64, and NAMEDATALEN won't even add up to kilobytes in any
realistic scenario, let along MB or GB.

--
Robert Haas
EDB: http://www.enterprisedb.com