Re: Order changes in PG16 since ICU introduction - Mailing list pgsql-hackers

From Jeff Davis
Subject Re: Order changes in PG16 since ICU introduction
Date
Msg-id 605324592391599a7ecd522087edbd00720793b7.camel@j-davis.com
Whole thread Raw
In response to Re: Order changes in PG16 since ICU introduction  ("Jonathan S. Katz" <jkatz@postgresql.org>)
Responses Re: Order changes in PG16 since ICU introduction
List pgsql-hackers
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


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