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[PATCH v24 5/5] doc: Add Collation Versions section. 2+ messages / 2 participants [nested] [flat]
* [PATCH v24 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 --wac7ysb48OaltWcw-- ^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: pg*.dll and *.pdb files in psqlODBC have no version numbers @ 2023-10-02 14:45 Tom Lane <[email protected]> 0 siblings, 0 replies; 2+ messages in thread From: Tom Lane @ 2023-10-02 14:45 UTC (permalink / raw) To: Mark Hill <[email protected]>; +Cc: [email protected] <[email protected]> Mark Hill <[email protected]> writes: > I posted this question to [email protected]<mailto:[email protected]> last week but on one has responded so posting here now. > A colleague noticed that the following files in the psqlODBC MSI for Windows have no version numbers: > ... > Does anyone know if that is be design or some other reason? Should they have version numbers? No idea, but actually the pgsql-odbc list would be the most authoritative place for answers, if you find none here. regards, tom lane ^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2023-10-02 14:45 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 v24 5/5] doc: Add Collation Versions section. Thomas Munro <[email protected]> 2023-10-02 14:45 Re: pg*.dll and *.pdb files in psqlODBC have no version numbers Tom Lane <[email protected]>
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