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authorMichael Paquier <michael@paquier.xyz>2018-07-07 08:10:53 +0900
committerMichael Paquier <michael@paquier.xyz>2018-07-07 08:10:53 +0900
commit378f78da86285aba98196201bf5db4eb6c5c0fed (patch)
tree752ffb15100fad7a3cbb57858f3d1e0003492829
parent02bfd6d415bfacdf16a273420fd86c67189556ff (diff)
downloadpostgresql-378f78da86285aba98196201bf5db4eb6c5c0fed.tar.gz
postgresql-378f78da86285aba98196201bf5db4eb6c5c0fed.zip
Add note in pg_rewind documentation about read-only files
When performing pg_rewind, the presence of a read-only file which is not accessible for writes will cause a failure while processing. This can cause the control file of the target data folder to be truncated, causing it to not be reusable with a successive run. Also, when pg_rewind fails mid-flight, there is likely no way to be able to recover the target data folder anyway, in which case a new base backup is the best option. A note is added in the documentation as well about. Reported-by: Christian H. Author: Michael Paquier Reviewed-by: Andrew Dunstan Discussion: https://postgr.es/m/20180104200633.17004.16377%40wrigleys.postgresql.org
-rw-r--r--doc/src/sgml/ref/pg_rewind.sgml20
1 files changed, 20 insertions, 0 deletions
diff --git a/doc/src/sgml/ref/pg_rewind.sgml b/doc/src/sgml/ref/pg_rewind.sgml
index ef0cc280d14..ed1625b5237 100644
--- a/doc/src/sgml/ref/pg_rewind.sgml
+++ b/doc/src/sgml/ref/pg_rewind.sgml
@@ -91,6 +91,26 @@ PostgreSQL documentation
<xref linkend="guc-full-page-writes"> must also be enabled. That is the
default.
</para>
+
+ <warning>
+ <para>
+ If <application>pg_rewind</application> fails while processing, then
+ the data folder of the target is likely not in a state that can be
+ recovered. In such a case, taking a new fresh backup is recommended.
+ </para>
+
+ <para>
+ <application>pg_rewind</application> will fail immediately if it finds
+ files it cannot write directly to. This can happen for example when
+ the source and the target server use the same file mapping for read-only
+ SSL keys and certificates. If such files are present on the target server
+ it is recommended to remove them before running
+ <application>pg_rewind</application>. After doing the rewind, some of
+ those files may have been copied from the source, in which case it may
+ be necessary to remove the data copied and restore back the set of links
+ used before the rewind.
+ </para>
+ </warning>
</refsect1>
<refsect1>