Horton

Re: Collation versioning

Julien Rouhaud <rjuju123@gmail.com>

View thread View on postgr.es
From: Julien Rouhaud <rjuju123@gmail.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Douglas Doole <dougdoole@gmail.com>, Thomas Munro <thomas.munro@enterprisedb.com>, Christoph Berg <myon@debian.org>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2019-10-31T13:21:03Z
Lists: pgsql-hackers 
Hello Thomas,

On Tue, May 28, 2019 at 9:00 PM Thomas Munro <thomas.munro@gmail.com> wrote:
>
> Since there's a chance of an "unconference" session on locale versions
> tomorrow at PGCon, here's a fresh rebase of the patchset to add
> per-database-object collation version tracking.  It doesn't handle
> default collations yet (not hard AFAIK, will try that soon), but it
> does work well enough to demonstrate the generate principal.  I won't
> attach the CHECK support just yet, because it needs more work, but the
> point of it was to demonstrate that pg_depend can handle this for all
> kinds of database objects in one standard way, rather than sprinkling
> collation version stuff all over the place in pg_index, pg_constraint,
> etc, and I think it did that already.

Are you planning to continue working on it?  For the record, that's
something needed to be able to implement a filter in REINDEX command
[1].

I'm not sending a review since the code isn't finished yet, but one
issue with current approach is that the WARNING message recommending
to issue a REINDEX can be issued when running the required REINDEX,
which is at best unhelpful:

# update pg_depend set refobjversion = 'a' || refobjversion where
refobjversion != '';

# reindex table t1;
WARNING:  01000: index "t1_val_idx" depends on collation 13330 version
"a153.97.35.8", but the current version is "153.97.35.8"
DETAIL:  The index may be corrupted due to changes in sort order.
HINT:  REINDEX to avoid the risk of corruption.
LOCATION:  index_check_collation_version, index.c:1263


[1]: https://www.postgresql.org/message-id/a81069b1-fdaa-ff40-436e-7840bd639ccf%402ndquadrant.com

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.