I'm writing to ask about using Slony switchover capability. I've never actually been able to make this work. I'm curious about whether this is a common experience or if, perhaps, there is something that I don't understand about how this should function. The environment that I have is a database that is in constant use. That is, there is always at least a low level of DML (inserts for the most part) occurring 24 x 7, 365 days a year. I've found that Slony will never be able to get a lock in order to perform the switchover and thus I'm left with tearing replication completely down and rebuilding from scratch if I have to perform maintenance on the primary. Do people find this unusual or is this somewhat expected — and the only time this actually functions as described in the documentation is if you are able to shutdown all database operations for a short period of time ( a few seconds even)?

What I do currently is use a VIP ( http://en.wikipedia.org/wiki/Virtual_IP_address ) to control how the various app servers are connecting to the primary database. I modify this to go to what was the slave, stop the slony processes, drop the slony schema and then restart replication from scratch.
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