Re: The Free Space Map: Problems and Opportunities

On Thu, Aug 26, 2021 at 5:59 AM Robert Haas <robertmhaas@gmail.com> wrote:
> Andres has been working -- I think for years now -- on replacing the
> buffer mapping table with a radix tree of some kind. That strikes me
> as very similar to what you're doing here. The per-relation data can
> then include not only the kind of stuff you're talking about but very
> fundamental things like how long it is and where its buffers are in
> the buffer pool. Hopefully we don't end up with dueling patches.

FTR I have a patch in development that adds a demand-paged (though
Anastasia recently suggested reconsidering that) per-SMGR relation
shmem object pool that initially tracks precisely "how long it is",
but I hope it would provide a hook to hang many other things on in
future that need coordination at the relation level, such as
synchronized scan position, and I hope, radix-based buffer mappings.
Could be relevant?   https://commitfest.postgresql.org/34/2933/ (I'll
rebase it soon).