Re: ICU Collations and Collation Updates

On Mon, 2025-04-14 at 19:24 +0200, Paul Foerster wrote:
> Hi Tom, hi Laurenz
> > On 14 Apr 2025, at 16:36, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >
> > Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> writes:
> > > You would have to build PostgreSQL yourself with a fixed version of ICU
> > > that you never upgrade if you want to avoid the problem.
> [...]
> > 2. It's at least *possible* to use your own fixed-version ICU
> > library if you're desperate enough. I don't think that would work
> > too well for libc; you're stuck with what the platform provides.
>
> That topic is interesting because I have a huge problem finding a downtime
> window for our applications to rebuild after the SLES upgrades. I am in the
> process of slowly changing everything to ICU. But limiting downtime is
> essential for me.
>
> We always build the PostgreSQL software from source, so if there's a way
> to bake the libicu directly into the software to never change it again
> (beside from recompiling of course), even when building new PostgreSQL
> versions, I'd very much appreciate if if you could let me know how I would
> do that.
>
> The necessity for reindex is a huge problem for us.

You cannot "bake in into" PostgreSQL, but you can grab the ICU source,
install it in /usr/local or similar and build PostgreSQL against that.
You will have to fiddle with CFLAGS and LDFLAGS so that the build process
uses the C headers and libraries from your build of the ICU library.

Yours,
Laurenz Albe