Horton

Re: Collation versioning

Christoph Berg <myon@debian.org>

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From: Christoph Berg <myon@debian.org>
To: Laurenz Albe <laurenz.albe@cybertec.at>
Cc: Thomas Munro <thomas.munro@gmail.com>, Michael Paquier <michael@paquier.xyz>, Julien Rouhaud <rjuju123@gmail.com>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Douglas Doole <dougdoole@gmail.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2019-11-08T09:20:03Z
Lists: pgsql-hackers 
Re: Laurenz Albe 2019-11-08 <3c3b9ff84d21acf3188558928249d04db84ea2e9.camel@cybertec.at>
> #3 is the best proposal, but there is still the need to run
> ALTER INDEX on all affected indexes to keep PostgreSQL from nagging.
> Perhaps the situation could be improved with a pg_upgrade option
> --i-know-my-indexes-are-fine that causes a result like #2.
> Together with a bold note in the release notes, this may relieve
> the pain.

Ack.

We should also try to make the actual commands more accessible.
Instead of having the user specify a version number we could as well
determine from the current state of the system as in
  ALTER INDEX ... DEPENDS ON 'version-number-I-never-heard-of-before'
could it just be
  ALTER INDEX ... COLLATION IS CURRENT
or, given the general action to take is reindexing, how about a no-op reindex?
  REINDEX INDEX ... METADATA ONLY

That might look less scary to the average end user.

Do we even think people upgrade PG and the OS at the same time?
pg_upgrade might frequently actually be invoked on an otherwise
unchanged system, so we could even make "collations are fine" the
default for pg_upgrade. And maybe have a switch like pg_upgrade --os-upgrade
that reverses this.

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.