Horton

Re: Built-in CTYPE provider

Laurenz Albe <laurenz.albe@cybertec.at>

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From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Noah Misch <noah@leadboat.com>, Jeff Davis <pgsql@j-davis.com>, Peter Eisentraut <peter@eisentraut.org>, Daniel Verite <daniel@manitou-mail.org>, Jeremy Schneider <schneider@ardentperf.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@postgresql.org
Date: 2024-07-18T08:05:34Z
Lists: pgsql-hackers 
On Wed, 2024-07-17 at 15:03 -0700, Noah Misch wrote:
> If I'm counting the votes right, you and Tom have voted that the feature's
> current state is okay, and I and Laurenz have voted that it's not okay.

Maybe I should expand my position.

I am very much for the built-in CTYPE provider.  When I said that I am against
changes in major versions, I mean changes that are likely to affect real-life
usage patterns.  If there are modifications affecting a code point that was
previously unassigned, it is *theoretically* possible, but very unlikely, that
someone has stored it in a database.  I would want to deliberate about any change
affecting such a code point, and if the change seems highly desirable, we can
consider applying it.

What I am against is routinely updating the built-in provider to adopt any changes
that Unicode makes.

To make a comparison with Tom's argument upthread: we have slightly changed how
floating point computations work, even though they are IMMUTABLE.  But I'd argue
that very few people build indexes on the results of floating point arithmetic
(and those who do are probably doing something wrong), so the risk is acceptable.
But people index strings all the time.

Yours,
Laurenz Albe

Commits

  1. Support PG_UNICODE_FAST locale in the builtin collation provider.

  2. Support Unicode full case mapping and conversion.

  3. Fix test failures when language environment is not UTF-8.

  4. Add unicode_strtitle() for Unicode Default Case Conversion.

  5. Use version for builtin collations.

  6. Fix convert_case(), introduced in 5c40364dd6.

  7. Inline basic UTF-8 functions.

  8. Support C.UTF-8 locale in the new builtin collation provider.

  9. Fix another warning, introduced by 846311051e.

  10. Address more review comments on commit 2d819a08a1.

  11. Fix unreachable code warning from commit 2d819a08a1.

  12. Introduce "builtin" collation provider.

  13. Catalog changes preparing for builtin collation provider.

  14. Unicode case mapping tables and functions.

  15. Add Unicode property tables.

  16. Documentation update for Standard Collations.

  17. Cleanup for unicode-update build target and test.

  18. Shrink Unicode category table.

  19. Make some error strings more generic

  20. pg_upgrade: copy locale and encoding information to new cluster.

  21. Update Unicode data to Unicode 15.0.0

  22. Create a new type category for "internal use" types.