Re: Order changes in PG16 since ICU introduction

Peter Eisentraut <peter.eisentraut@enterprisedb.com>

From: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
To: Sandro Santilli <strk@kbt.io>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: Regina Obe <lr@pcorp.us>, pgsql-hackers@lists.postgresql.org, Jeff Davis <pgsql@j-davis.com>
Date: 2023-04-24T15:10:04Z
Lists: pgsql-hackers
On 21.04.23 19:14, Peter Eisentraut wrote:
> On 21.04.23 19:09, Sandro Santilli wrote:
>> On Fri, Apr 21, 2023 at 11:48:51AM -0400, Tom Lane wrote:
>>> "Regina Obe" <lr@pcorp.us> writes:
>>>
>>>> https://trac.osgeo.org/postgis/ticket/5375
>>>
>>> If they actually are using locale C, I would say this is a bug.
>>> That should designate memcmp sorting and nothing else.
>>
>> Sounds like a bug to me. This is happening with a PostgreSQL cluster
>> created and served by a build of commit c04c6c5d6f :
>>
>>    =# select version();
>>    PostgreSQL 16devel on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 
>> 11.3.0-1ubuntu1~22.04) 11.3.0, 64-bit
>>    =# show lc_collate;
>>    C
>>    =# select '+' < '-';
>>    f
> 
> If the database is created with locale provider ICU, then lc_collate 
> does not apply here, so the result might be correct (depending on what 
> locale you have set).

The GUC settings lc_collate and lc_ctype are from a time when those 
locale settings were cluster-global.  When we made those locale settings 
per-database (PG 8.4), we kept them as read-only.  As of PG 15, you can 
use ICU as the per-database locale provider, so what is being attempted 
in the above example is already meaningless before PG 16, since you need 
to look into pg_database to find out what is really happening.

I think we should just remove the GUC parameters lc_collate and lc_ctype.




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.