public inbox for [email protected]help / color / mirror / Atom feed
[PATCH v25 5/5] doc: Add Collation Versions section. 2+ messages / 2 participants [nested] [flat]
* [PATCH v25 5/5] doc: Add Collation Versions section. @ 2020-03-11 02:01 Thomas Munro <[email protected]> 0 siblings, 0 replies; 2+ messages in thread From: Thomas Munro @ 2020-03-11 02:01 UTC (permalink / raw) Supply a brief introduction to collation version concepts. Author: Thomas Munro Reviewed-by: Julien Rouhaud Discussion: https://postgr.es/m/CAEepm%3D0uEQCpfq_%2BLYFBdArCe4Ot98t1aR4eYiYTe%3DyavQygiQ%40mail.gmail.com --- doc/src/sgml/charset.sgml | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/doc/src/sgml/charset.sgml b/doc/src/sgml/charset.sgml index 4b4563c5b9..c537bdfc28 100644 --- a/doc/src/sgml/charset.sgml +++ b/doc/src/sgml/charset.sgml @@ -948,6 +948,41 @@ CREATE COLLATION ignore_accents (provider = icu, locale = 'und-u-ks-level1-kc-tr </tip> </sect3> </sect2> + + <sect2 id="collation-versions"> + <title>Collation Versions</title> + + <para> + The ordering defined by a collation is not necessarily fixed over time. + If a collation changes for any reason, persistent data structures such as + b-trees that depend on a stable ordering of text might be corrupted. + <productname>PostgreSQL</productname> defends against this by recording + the current version of each referenced collation for any index that + depends on it in the + <link linkend="catalog-pg-depend"><structname>pg_depend</structname></link> + catalog, if the collation provider makes it available. If the provider + later begins to report a different version, a warning will be reported + when the index is accessed, until either the <xref linkend="sql-reindex"/> + or the <xref linkend="sql-alterindex"/> command is used to update the + version. + </para> + <para> + Version information is available for collations from the + <literal>icu</literal> provider on all operating systems. For the + <literal>libc</literal> provider, versions are currently only available + on systems using the GNU C library (most Linux systems). + </para> + + <note> + <para> + When using the GNU C library for collations, the C library's version + is used as a proxy for the collation version. Many Linux distributions + change collation definitions only when upgrading the C library, but this + approach is imperfect as maintainers are free to back-port newer + collation definitions to older C library releases. + </para> + </note> + </sect2> </sect1> <sect1 id="multibyte"> -- 2.20.1 --lrZ03NoBR/3+SXJZ-- ^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: Various small doc improvements; plpgsql, schemas, permissions, oidvector @ 2023-09-25 12:00 Karl O. Pinc <[email protected]> 0 siblings, 0 replies; 2+ messages in thread From: Karl O. Pinc @ 2023-09-25 12:00 UTC (permalink / raw) To: Daniel Gustafsson <[email protected]>; +Cc: pgsql-hackers On Mon, 25 Sep 2023 09:26:38 +0200 Daniel Gustafsson <[email protected]> wrote: > > On 25 Sep 2023, at 00:57, Karl O. Pinc <[email protected]> wrote: > > > I have made various, mostly unrelated to each other, > > small improvements to the documentation. > While I agree it's subjective, I don't think adding a new section or > paragraph qualifies as short or small. I would prefer if each > (related) change is in a single commit with a commit message which > describes the motivation for the change. A reviewer can second-guess > the rationale for the changes, but they shouldn't have to. Will do. Is there a preferred data format or should I send each patch in a separate attachment with description? > The resulting patchset can all be in the same thread though. Thanks. Regards, Karl <[email protected]> Free Software: "You don't pay back, you pay forward." -- Robert A. Heinlein ^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2023-09-25 12:00 UTC | newest] Thread overview: 2+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2020-03-11 02:01 [PATCH v25 5/5] doc: Add Collation Versions section. Thomas Munro <[email protected]> 2023-09-25 12:00 Re: Various small doc improvements; plpgsql, schemas, permissions, oidvector Karl O. Pinc <[email protected]>
This inbox is served by agora; see mirroring instructions for how to clone and mirror all data and code used for this inbox