Horton

Re: Collation versioning

Thomas Munro <thomas.munro@gmail.com>

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From: Thomas Munro <thomas.munro@gmail.com>
To: Julien Rouhaud <rjuju123@gmail.com>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Michael Paquier <michael@paquier.xyz>, Robert Haas <robertmhaas@gmail.com>, Laurenz Albe <laurenz.albe@cybertec.at>, Douglas Doole <dougdoole@gmail.com>, Christoph Berg <myon@debian.org>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2020-09-19T22:35:56Z
Lists: pgsql-hackers 
On Thu, Sep 17, 2020 at 5:41 AM Julien Rouhaud <rjuju123@gmail.com> wrote:
> On Tue, Sep 15, 2020 at 2:26 PM Peter Eisentraut
> <peter.eisentraut@2ndquadrant.com> wrote:
> > I'm confused now.  I think we had mostly agreed on the v28 patch set,
> > without this additional AM flag.  There was still some discussion on
> > what the AM flag's precise semantics should be.  Do we want to work that
> > out first?
>
> That was my understanding too, but since Michael raised a concern I
> wrote some initial implementation for that part.  I'm assuming that
> this new flag will raise some new discussion, and I hope this can be
> discussed later, or at least in parallel, without interfering with the
> rest of the patchset.

If we always record dependencies we'll have the option to invent
clever ways to ignore them during version checking in later releases.

> > Btw., I'm uneasy about the term "stable collation order".  "Stable" has
> > an established meaning for sorting.  It's really about whether the AM
> > uses collations at all, right?
>
> Well, at the AM level I guess it's only about whether it's using some
> kind of sorting or not, as the collation information is really at the
> opclass level.  It makes me realize that this approach won't be able
> to cope with an index built using (varchar|text)_pattern_ops, and
> that's probably something we should handle correctly.

Hmm.

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.