On Thu, Sep 14, 2017 at 6:28 PM, Gianluca Cecchi <gianluca.cecchi(a)gmail.com&gt; wrote: Should be enough, if it's a compatible change. Otherwise, it requires upgrading the pg data. There is a utility for this, called pg_upgrade, and in el/fedora there is a useful wrapper command for it, 'postgresql-setup --upgrade'. On a related subject, in 4.2 we are going to require PG 9.5 (from SCL, on el7). You can search the devel list archives for details, as well as bugzilla: https://bugzilla.redhat.com/showdependencytree.cgi?id=1106547&hide_re... In particular, see bug 1480624. Due to it, we decided to call in engine-setup 'postresql-setup --upgrade', instead of calling pg_upgrade directly. Not sure you need that, but might be a bit safer, to make sure everything starts in the correct order. Indeed. Here, too, I'd only exit global maint, mainly to use the opportunity to test the HA functionality. Best, -- Didi