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Re: Order changes in PG16 since ICU introduction

Jeff Davis <pgsql@j-davis.com>

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From: Jeff Davis <pgsql@j-davis.com>
To: "Jonathan S. Katz" <jkatz@postgresql.org>, Robert Haas <robertmhaas@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Regina Obe <lr@pcorp.us>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, Sandro Santilli <strk@kbt.io>, pgsql-hackers@lists.postgresql.org
Date: 2023-05-17T03:23:16Z
Lists: pgsql-hackers

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On Tue, 2023-05-16 at 15:35 -0400, Jonathan S. Katz wrote:
> +          Sensitivity when determining equality, with
> +          <literal>level1</literal> the least sensitive and
> +          <literal>identic</literal> the most sensitive. See <xref
> +          linkend="icu-collation-levels"/> for details.
> 
> This discusses equality sensitivity, but I'm not sure if I understand
> that term here. The ICU docs seem to call these "strengths"[1], maybe
> we 
> use that term to be consistent with upstream?

"Sensitivity" comes from "case sensitivity" which is more clear to me
than "strength". I added the term "strength" to correspond to the
unicode terminology, but I kept sensitivity and I tried to make it
slightly more clear.

Other than that, and I took your suggestions almost verbatim. Patch
attached. Thank you!

I also made a few other changes:

  * added paragraph transformation of '' or 'root' to the 'und'
language (root collation)
  * added paragraph that the "identic" level still performs some basic
normalization
  * added example for when full normalization matters

I should also say that I don't really understand the case when "kc" is
set to true and "ks" is level 2 or higher. If someone has an example of
where that matters, let me know.

Regards,
	Jeff Davis

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Introduce "builtin" collation provider.

  2. ICU: do not convert locale 'C' to 'en-US-u-va-posix'.

  3. initdb: change default --locale-provider back to libc.

  4. CREATE DATABASE: make LOCALE apply to all collation providers.

  5. Remove read-only server settings lc_collate and lc_ctype

  6. ICU: use uloc_getDefault() for initdb.

  7. Doc fixes for commit 1e16af8ab5.

  8. Doc: fix some rendering problems in the PDF docs build.

  9. Doc improvements for language tags and custom ICU collations.

  10. ICU: check for U_STRING_NOT_TERMINATED_WARNING.

  11. Reduce icu_validation_level default to WARNING.

  12. Revert "ICU: do not convert locale 'C' to 'en-US-u-va-posix'."

  13. Fix initdb --no-locale.

  14. Avoid character classification in regex escape parsing.