I'm planning my upgrade from 9.1.5 to 9.1.6 on some master and
streaming-replication standby pairs and have some questions:
Generally:
http://www.postgresql.org/docs/9.1/static/warm-standby.html section
25.2.1 says:
"...it is likely that running different minor release levels on primary
and standby servers will work successfully. However, no formal support
for that is offered and you are advised to keep primary and standby
servers at the same release level as much as possible. When updating to
a new minor release, the safest policy is to update the standby servers
first — a new minor release is more likely to be able to read WAL files
from a previous minor release than vice versa."
My mental translation of this is "...try updating the standby first and
hope it works - if not and you at some point find your standby is scrod,
you're on your own...we warned you..."
Is this the correct interpretation? I'd feel better if there were a
documented approved upgrade process for systems using streaming
replication and that the release notes would specify when a minor
upgrade involves WAL file changes that require special handling (and it
would be nice if PostgreSQL would detect dangerous format mismatch
issues and refuse to start).
Specifically:
Neither the update release notes on the wiki
(http://wiki.postgresql.org/wiki/20120924updaterelease as of this
writing) nor the release notes
http://www.postgresql.org/docs/9.1/static/release-9-1-6.html nor news
http://www.postgresql.org/about/news/1416/ indicate that any special
handling is required on standby servers. Can anyone confirm if that is
correct or, if not, what additional steps are prudent?
Cheers,
Steve