Re: introduce dynamic shared memory registry

On 12/4/23 22:46, Nathan Bossart wrote:
> Every once in a while, I find myself wanting to use shared memory in a
> loadable module without requiring it to be loaded at server start via
> shared_preload_libraries. The DSM API offers a nice way to create and
> manage dynamic shared memory segments, so creating a segment after server
> start is easy enough. However, AFAICT there's no easy way to teach other
> backends about the segment without storing the handles in shared memory,
> which puts us right back at square one.
>
> The attached 0001 introduces a "DSM registry" to solve this problem. The
> API provides an easy way to allocate/initialize a segment or to attach to
> an existing one. The registry itself is just a dshash table that stores
> the handles keyed by a module-specified string. 0002 adds a test for the
> registry that demonstrates basic usage.
>
> I don't presently have any concrete plans to use this for anything, but I
> thought it might be useful for extensions for caching, etc. and wanted to
> see whether there was any interest in the feature.

Notwithstanding any dragons there may be, and not having actually looked
at the the patches, I love the concept! +<many>

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