Right, that's about the right ballpark - tens of second for unplanned events (failover), a couple of seconds for planned events (switchover). We can have a len

Right, that's about the right ballpark - tens of second for unplanned events (failover), a couple of seconds for planned events (switchover). We can have a lenghty discussion about all the caveats and options, but in my experience trying to reduce the times below these (somewhat vague) thresholds is mostly pointless. For switchovers, a couple of seconds should not be a big deal - you can pick when it happens, and there are ways to make it non-disruptive for the application (i.e. you can design the app to tolerate this, or you can use PAUSE in pgbouncer, or whatever). For failovers, the "tens of seconds" may seem a bit too high, but most of the time will be spent determining whether to do the failover or not. Make it too aggressive and you'll be sad. Ultimately, it's a matter of money. People sometime say things like "It has to be 24/7, absolutely not outages, it's a non-negotiable critical business requirement." A good response that is "So you're telling me a 60-second outage of this system will put you out of business?"