Re: Fwd: [PATCH] Add zstd compression for TOAST using extended header format

On Thu, Dec 18, 2025 at 5:44 PM Michael Paquier <michael@paquier.xyz> wrote:
> On Thu, Dec 18, 2025 at 10:44:22PM +0100, Dharin Shah wrote:
> > I'll share the detailed benchmark script with the next patch revision. But
> > also a potential path forward could be that we could just fully replace
> > pglz (can bring it up later in different thread)
>
> I don't think that we will ever be able to remove pglz.  It would be
> nice, as final result of course, but I also expect that not being able
> to decompress pglz data is going to lead to a lot of user pain.  That
> would be also very expensive to check at upgrade for large instances.
>

Agreed that I can't see pglz being removed any time soon, if ever.
Thinking through what a conversion process would look like seems
unwieldy at best, so I think we definitely need it for backwards
compatibility, plus I think it is useful to have a self-contained
option. I'd almost suggest we should look at replacing lz4, but I
don't think that is significantly easier, it just has a smaller, more
invested, blast radius. That said, I do suspect ztsd could quickly
become a popular recommendation and/or default among users /
consultants / service providers.

Robert Treat
https://xzilla.net