public inbox for [email protected]
help / color / mirror / Atom feed[PATCH v27 5/5] Doc: Add Collation Versions section.
2+ messages / 2 participants
[nested] [flat]
* [PATCH v27 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
--o56keubw4jpehgac--
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: 002_pg_upgrade is broken for custom install
@ 2025-04-04 11:53 Álvaro Herrera <[email protected]>
0 siblings, 0 replies; 2+ messages in thread
From: Álvaro Herrera @ 2025-04-04 11:53 UTC (permalink / raw)
To: Ashutosh Bapat <[email protected]>; +Cc: pgsql-hackers
On 2025-Apr-04, Ashutosh Bapat wrote:
> connection error: 'psql: error: connection to server on socket
> "/tmp/LiPa_UJpSb/.s.PGSQL.13779" failed: FATAL: database "regression"
> does not exist'
> while running '/home/ashutosh/work/units/pghead/build/dev/bin/psql
> --no-psqlrc --no-align --tuples-only --quiet --dbname port=13779
> host=/tmp/LiPa_UJpSb dbname='regression' --file - --variable
> ON_ERROR_STOP=1' at
> /home/ashutosh/work/units/pghead/coderoot/pg/src/test/perl/PostgreSQL/Test/Cluster.pm
> line 2256.
> # Postmaster PID for node "old_node" is 779230
> ### Stopping node "old_node" using mode immediate
This is saying that Cluster->psql() (line 2256) tried to connect to
database regression and failed unexpectedly. Is your "olddump" file
created with pg_dumpall from a cluster that contains such a database?
If not, then the test isn't broken, you're just not operating it
correctly :-)
Maybe the failure could be clearer: rather than blindly trying to
connect to regression, first see if it exists, and die with a hard
failure ("your old dump must contain database regression") if not.
Alternatively, if the regression database doesn't exist, just skip that
part.
--
Álvaro Herrera Breisgau, Deutschland — https://www.EnterpriseDB.com/
^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2025-04-04 11:53 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 v27 5/5] Doc: Add Collation Versions section. Thomas Munro <[email protected]>
2025-04-04 11:53 Re: 002_pg_upgrade is broken for custom install Álvaro Herrera <[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