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[PATCH v28 5/5] Doc: Add Collation Versions section. 2+ messages / 2 participants [nested] [flat]
* [PATCH v28 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 <[email protected]> Reviewed-by: Julien Rouhaud <[email protected]> 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..12a82ff18c 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 issued + 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 --gclmslubawp3yaq7-- ^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: Some cleanup of pg_stat_statements tests @ 2026-01-20 12:36 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 2+ messages in thread From: Álvaro Herrera @ 2026-01-20 12:36 UTC (permalink / raw) To: Michael Paquier <[email protected]>; +Cc: Postgres hackers <[email protected]> On 2026-Jan-20, Michael Paquier wrote: > While looking at this area of the code, I have noticed that the new > "squashing" test is not consistent with the rest of the test suite, > re-creating the extension for nothing. > > The structure of the test is to have the "cleanup" phase second to > last, so as there is no need to create multiple times the extensions. Huh, yeah, agreed on this change. > In passing, I'd like to suggest that REGRESS in the Makefile uses one > item per line, to minimize diffs when we add new stuff. Absolutely. > Any thoughts or objections about the attached? No objections here. -- Álvaro Herrera Breisgau, Deutschland — https://www.EnterpriseDB.com/ "Java is clearly an example of money oriented programming" (A. Stepanov) ^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2026-01-20 12:36 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 v28 5/5] Doc: Add Collation Versions section. Thomas Munro <[email protected]> 2026-01-20 12:36 Re: Some cleanup of pg_stat_statements tests Álvaro Herrera <[email protected]>
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