From eb270b00b2d60e751545d4b808642395c901b668 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Sat, 7 Jul 2018 08:10:10 +0900 Subject: [PATCH] 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 --- doc/src/sgml/ref/pg_rewind.sgml | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/doc/src/sgml/ref/pg_rewind.sgml b/doc/src/sgml/ref/pg_rewind.sgml index 520d843f0e..ee35ce18b0 100644 --- a/doc/src/sgml/ref/pg_rewind.sgml +++ b/doc/src/sgml/ref/pg_rewind.sgml @@ -95,6 +95,26 @@ PostgreSQL documentation are currently on by default. must also be set to on, but is enabled by default. + + + + If pg_rewind 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. + + + + pg_rewind 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 + pg_rewind. 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. + + -- 2.40.0