Re: head fails to build on SLES 12 (wal_compression=zstd)

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Thu, Mar 31, 2022 at 11:44 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> In view of 51c0d186d ("Allow parallel zstd compression"), I agree
>> that some clarity about the minimum supported version of zstd
>> seems essential. I don't want to be dealing with threading bugs
>> in ancient zstd versions. However, why do you suggest 1.3.7 in
>> particular?

> One thing to note is that apparently threading wasn't enabled in the
> default build before 1.5.0, which was released in May 2021, but it did
> exist as an option in the code for some period of time prior to that.
> I don't know how long exactly. I don't want to jump to the conclusion
> that other people's old versions are full of bugs, but if that should
> happen to be true here, there's some chance that PostgreSQL users
> won't be exposed to them just because threading wasn't enabled by
> default until quite recently.

Hm. After rereading 51c0d186d I see that we're not asking for
parallel compression unless the user tells us to, so I guess
our fallback answer for any complaints in that area can be
"if it hurts, don't do it". Still, I like the idea of having
a well-defined minimum zstd version that we consider supported.
The evident fact that their APIs are still changing (or at
least have done so within the memory of LTS platforms) makes
that fairly pressing. Question is what to set the minimum to.

regards, tom lane