Horton

Re: Collation versioning

Christoph Berg <myon@debian.org>

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From: Christoph Berg <myon@debian.org>
To: Thomas Munro <thomas.munro@enterprisedb.com>
Cc: Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2018-09-05T10:35:25Z
Lists: pgsql-hackers 
Re: Thomas Munro 2018-09-04 <CAEepm=0uEQCpfq_+LYFBdArCe4Ot98t1aR4eYiYTe=yavQygiQ@mail.gmail.com>
> I was reminded about that by recent news
> about an upcoming glibc/CLDR resync that is likely to affect
> PostgreSQL users (though, I guess, probably only when they do a major
> OS upgrade).

Or replicating/restoring a database to a newer host.

> ... or, on a Debian system using the locales package, like this:
> 
> libc_collation_version_command = 'dpkg -s locales | grep Version: |
> sed "s/Version: //"'

Ugh. This sounds horribly easy to get wrong on the user side. I could
of course put that preconfigured into the Debian packages, but that
would leave everyone not using any of the standard distro packagings
in the rain.

> Does anyone know
> of a way to extract a version string from glibc using existing
> interfaces?  I heard there was an undocumented way but I haven't been
> able to find it -- probably because I was, erm, looking in the
> documentation.

That sounds more robust. Googling around:

https://www.linuxquestions.org/questions/linux-software-2/how-to-check-glibc-version-263103/

#include <stdio.h>
#include <gnu/libc-version.h>
int main (void) { puts (gnu_get_libc_version ()); return 0; }

$ ./a.out
2.27

Hopefully that version info is fine-grained enough.

Christoph

Commits

  1. Doc: Document known problem with Windows collation versions.

  2. Add collation versions for FreeBSD.

  3. Tolerate version lookup failure for old style Windows locale names.

  4. Track collation versions for indexes.

  5. Add pg_depend.refobjversion.

  6. Remove pg_collation.collversion.

  7. Fix the MSVC build for versions 2015 and later.

  8. Add collation versions for Windows.

  9. Implement type regcollation

  10. Use libc version as a collation version on glibc systems.

  11. Make type "name" collation-aware.