Re: ICU for global collation

At Thu, 15 Sep 2022 18:41:31 +0300, Marina Polyakova <m(dot)polyakova(at)postgrespro(dot)ru> wrote in
> P.S. While working on the patch, I discovered that UTF8 encoding is
> always used for the ICU provider in initdb unless it is explicitly
> specified by the user:
>
> if (!encoding && locale_provider == COLLPROVIDER_ICU)
> encodingid = PG_UTF8;
>
> IMO this creates additional errors for locales with other encodings:
>
> $ initdb --locale de_DE(dot)iso885915(at)euro --locale-provider icu
> --icu-locale de-DE
> ...
> initdb: error: encoding mismatch
> initdb: detail: The encoding you selected (UTF8) and the encoding that
> the selected locale uses (LATIN9) do not match. This would lead to
> misbehavior in various character string processing functions.
> initdb: hint: Rerun initdb and either do not specify an encoding
> explicitly, or choose a matching combination.
>
> And ICU supports many encodings, see the contents of pg_enc2icu_tbl in
> encnames.c...

It seems to me the best default that fits almost all cases using icu
locales.

So, we need to specify encoding explicitly in that case.

$ initdb --encoding iso-8859-15 --locale de_DE(dot)iso885915(at)euro --locale-provider icu --icu-locale de-DE

However, I think it is hardly understantable from the documentation.

(I checked this using euc-jp [1] so it might be wrong..)

[1] initdb --encoding euc-jp --locale ja_JP.eucjp --locale-provider icu --icu-locale ja-x-icu

regards.

--
Kyotaro Horiguchi
NTT Open Source Software Center