>A pg_dump from one system or the other will effectively overwrite the database it is restored to, so any changes in one system or the other will be lost yes, as said, the pre-condition is that she is the one and only possible data producer.
or you can just take a full dump from one box and import it on the other any time you switch. If it's not a big db it should probably be quicker than any alternative approach.
A pg_dump from one system or the other will effectively overwrite the database it is restored to, so any changes in one system or the other will be lost unless processes are put in place to move that data to a staging area before the reload. The issue here is that it is a data and structure synchronization problem, which isn't something solved very easily using Postgresql's core tools. Synchronizing the data using Bash/Python, FDW's etc is reasonably straightforward, but synchronizing the DDL changes will require some care.
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