Horton

Re: Built-in CTYPE provider

Noah Misch <noah@leadboat.com>

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From: Noah Misch <noah@leadboat.com>
To: Laurenz Albe <laurenz.albe@cybertec.at>
Cc: Jeff Davis <pgsql@j-davis.com>, Peter Eisentraut <peter@eisentraut.org>, Daniel Verite <daniel@manitou-mail.org>, Jeremy Schneider <schneider@ardentperf.com>, Tom Lane <tgl@sss.pgh.pa.us>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@postgresql.org
Date: 2024-07-18T14:00:15Z
Lists: pgsql-hackers 
On Thu, Jul 18, 2024 at 10:05:34AM +0200, Laurenz Albe wrote:
> 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.

Given all the messages on this thread, if the feature remains in PostgreSQL, I
advise you to be ready to tolerate PostgreSQL "routinely updating the built-in
provider to adopt any changes that Unicode makes".  Maybe someone will change
something in v18 so it's not like that, but don't count on it.

Would you like to change your vote to "okay", keep your vote at "not okay", or
change it to an abstention?

> 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.

Agreed.

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.