title: PostgreSQL availability and merges
body: <p>Is there a PostgreSQL HA solution that can handle a splitbrain situation gracefully.  To elaborate, the system i'm working on is expected to run in several areas with users close to the servers there and connectivity between the zones is known to be questionable.  I'd like for the users to be able to continue using the system in a degraded state (without updates from disconnected zones) and for a sensible merge once they come back online. </p>