Horton

Re: Collation versioning

Peter Eisentraut <peter.eisentraut@2ndquadrant.com>

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From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
To: Thomas Munro <thomas.munro@enterprisedb.com>, Christoph Berg <myon@debian.org>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2019-10-02T18:52:31Z
Lists: pgsql-hackers 
On 2018-09-05 23:18, Thomas Munro wrote:
> On Wed, Sep 5, 2018 at 12:10 PM Christoph Berg <myon@debian.org> wrote:
>>> So, it's not ideal but perhaps worth considering on the grounds that
>>> it's better than nothing?
>>
>> Ack.
> 
> Ok, here's a little patch like that.
> 
> postgres=# select collname, collcollate, collversion from pg_collation
> where collname = 'en_NZ';
>  collname | collcollate | collversion
> ----------+-------------+-------------
>  en_NZ    | en_NZ.utf8  | 2.24
> (1 row)

After, um, briefly sleeping on this, I would like to go ahead with this.

There is ongoing work to make ICU available globally, and as part of
that I've also proposed a way to make the collation version tracking
work on a database level.

This here would be a useful piece on the overall picture.  Independent
of what becomes of the ICU effort, we could have glibc collation version
tracking completely working for PG13.

The only open question on this patch was whether it's a good version to
use.  I think based on subsequent discussions, there was the realization
that this is the best we can do and better than nothing.

In the patch, I would skip the configure test and just do

#ifdef __GLIBC__

directly.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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.