Horton

Re: Collation versioning

Stephen Frost <sfrost@snowman.net>

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From: Stephen Frost <sfrost@snowman.net>
To: Douglas Doole <dougdoole@gmail.com>
Cc: Thomas Munro <thomas.munro@enterprisedb.com>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Christoph Berg <myon@debian.org>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2018-09-18T22:09:31Z
Lists: pgsql-hackers 
Greetings,

* Douglas Doole (dougdoole@gmail.com) wrote:
> > The CHECK constraint doesn't need to directly track that information-
> > it should have a dependency on the column in the table and that's where
> > the information would be recorded about the current collation version.
> 
> Just to have fun throwing odd cases out, how would something like this be
> recorded?
> 
> Database default collation: en_US
> 
> CREATE TABLE t (c1 TEXT, c2 TEXT, c3 TEXT,
>      CHECK (c1 COLLATE "fr_FR" BETWEEN c2 COLLATE "fr_FR" AND c3 COLLATE
> "fr_FR"));
> 
> You could even be really warped and apply multiple collations on a single
> column in a single constraint.

Once it gets to an expression and not just a simple check, I'd think
we'd record it in the expression..

Thanks!

Stephen

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.