On Mon, Jul 1, 2019 at 1:34 PM Julien Rouhaud <rjuju...@gmail.com> wrote: > I have a vague recollection that ICU was providing some backward > compatibility so that even if you upgrade your lib you can still get > the sort order that was active when you built your indexes, though > maybe for a limited number of versions.
That isn't built in. Another database system that uses ICU handles this by linking to multiple versions of ICU, each with its own UCA version and associated collations. I don't think that we want to go there, so it makes sense to make an upgrade that crosses ICU or glibc versions as painless as possible. Note that ICU does at least provide a standard way to use multiple versions at once; the symbol names have the ICU version baked in. You're actually calling the functions using the versioned symbol names without realizing it, because there is macro trickery involved. -- Peter Geoghegan
