Jeff Davis f69319f2f1 Support C.UTF-8 locale in the new builtin collation provider.
The builtin C.UTF-8 locale has similar semantics to the libc locale of
the same name. That is, code point sort order (fast, memcmp-based)
combined with Unicode semantics for character operations such as
pattern matching, regular expressions, and
LOWER()/INITCAP()/UPPER(). The character semantics are based on
Unicode simple case mappings.

The builtin provider's C.UTF-8 offers several important advantages
over libc:

 * faster sorting -- benefits from additional optimizations such as
   abbreviated keys and varstrfastcmp_c
 * faster case conversion, e.g. LOWER(), at least compared with some
   libc implementations
 * available on all platforms with identical semantics, and the
   semantics are stable, testable, and documentable within a given
   Postgres major version

Being based on memcmp, the builtin C.UTF-8 locale does not offer
natural language sort order. But it is an improvement for most use
cases that might otherwise use libc's "C.UTF-8" locale, as well as
many use cases that use libc's "C" locale.

Discussion: https://postgr.es/m/ff4c2f2f9c8fc7ca27c1c24ae37ecaeaeaff6b53.camel%40j-davis.com
Reviewed-by: Daniel Vérité, Peter Eisentraut, Jeremy Schneider
2024-03-19 15:24:41 -07:00
2024-02-28 15:17:23 +04:00
2019-12-18 09:13:13 +01:00
2022-12-04 15:23:00 -05:00
2024-01-03 20:49:05 -05:00
2020-02-10 20:47:50 +01:00
2024-02-28 15:17:23 +04:00
2024-02-28 14:53:52 -06:00

PostgreSQL Database Management System

This directory contains the source code distribution of the PostgreSQL database management system.

PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.

Copyright and license information can be found in the file COPYRIGHT.

General documentation about this version of PostgreSQL can be found at: https://www.postgresql.org/docs/devel/
In particular, information about building PostgreSQL from the source code can be found at: https://www.postgresql.org/docs/devel/installation.html

The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.

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