diff options
| -rw-r--r-- | doc/src/sgml/ref/alter_collation.sgml | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/doc/src/sgml/ref/alter_collation.sgml b/doc/src/sgml/ref/alter_collation.sgml index 558bea0c603..892c4665655 100644 --- a/doc/src/sgml/ref/alter_collation.sgml +++ b/doc/src/sgml/ref/alter_collation.sgml @@ -104,9 +104,9 @@ ALTER COLLATION <replaceable>name</replaceable> SET SCHEMA <replaceable>new_sche <title>Notes</title> <para> - When using collations provided by the ICU library, the ICU-specific version - of the collator is recorded in the system catalog when the collation object - is created. When the collation is used, the current version is + When a collation object is created, the provider-specific version of the + collation is recorded in the system catalog. When the collation is used, + the current version is checked against the recorded version, and a warning is issued when there is a mismatch, for example: <screen> @@ -117,21 +117,24 @@ HINT: Rebuild all objects affected by this collation and run ALTER COLLATION pg A change in collation definitions can lead to corrupt indexes and other problems because the database system relies on stored objects having a certain sort order. Generally, this should be avoided, but it can happen - in legitimate circumstances, such as when + in legitimate circumstances, such as when upgrading the operating system + to a new major version or when using <command>pg_upgrade</command> to upgrade to server binaries linked with a newer version of ICU. When this happens, all objects depending on the collation should be rebuilt, for example, using <command>REINDEX</command>. When that is done, the collation version can be refreshed using the command <literal>ALTER COLLATION ... REFRESH VERSION</literal>. This will update the system catalog to record the - current collator version and will make the warning go away. Note that this + current collation version and will make the warning go away. Note that this does not actually check whether all affected objects have been rebuilt correctly. </para> <para> When using collations provided by <literal>libc</literal>, version information is recorded on systems using the GNU C library (most Linux - systems), FreeBSD and Windows. + systems), FreeBSD and Windows. When using collations provided by ICU, the + version information is provided by the ICU library and is available on all + platforms. </para> <note> <para> |