I'm running PostgreSQL v9.3.4 on Oracle Linux v6.7 (aka CentOS, aka RedHat). I would like to upgrade to the new PostgreSQL version v9.3.5, and one of my fellow DBA's posed an interesting question that could save us a few minutes of downtime:
QUESTION: If we leave the database running and do a "yum update", won't the old binaries that are in use be OK (because the filesystem won't release them until the file handle is closed) so that we can minimize downtime to simply a stop/start?
So the upgrade process would be:
I think this could be potentially dangerous, as what if v9.3.4 is running and then needs to re-spawn something... it would grab the v9.3.5 binary. I think that the only safe way is:
Sure, we could install the new binaries into a different directory like what happens during major releases (e.g. 9.0 -> 9.4)... but that seems like too much hassle for a point release and a few minutes of downtime saved.