Please note that I'm open for any other replication method that would allow
better scalability. One of the best option would be to have Multi-master
setup though I haven't seen any documentation around the support for such
capability by Postgres.
Have you considered third-party tools like Bucardo? It, particularly, was designed for replicating across unreliable WAN links, and is currently in active use replicating large volumes of data between sites separated by oceans and continents.
It has overhead, and is asynchronous, but supports multi-master (where N > 2), and will simply queue changes for replication in the event of link failure.
It may not suit your needs, but it's probably worth considering
rls
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:wq
