Re: ICU integration

Peter Eisentraut <peter.eisentraut@2ndquadrant.com> writes:
> On 9/6/16 1:40 PM, Doug Doole wrote:
>> We carried the ICU version numbers around on our collation and locale
>> IDs (such as fr_FR%icu36) . The database would load multiple versions of
>> the ICU library so that something created with ICU 3.6 would always be
>> processed with ICU 3.6. This avoided the problems of trying to change
>> the rules on the user. (We'd always intended to provide tooling to allow
>> the user to move an existing object up to a newer version of ICU, but we
>> never got around to doing it.) In the code, this meant we were
>> explicitly calling the versioned API so that we could keep the calls
>> straight.

> I understand that in principle, but I don't see operating system
> providers shipping a bunch of ICU versions to facilitate that.  They
> will usually ship one.

I agree with that estimate, and I would further venture that even if we
wanted to bundle ICU into our tarballs, distributors would rip it out
again on security grounds.  I am dead certain Red Hat would do so; less
sure that other vendors have similar policies, but it seems likely.
They don't want to have to fix security bugs in more than one place.

This is a problem, if ICU won't guarantee cross-version compatibility,
because it destroys the argument that moving to ICU would offer us
collation behavior stability.
        regards, tom lane