When it comes to maintaining a single PostgreSQL cluster with a single source of WAL files, our job is an easy one. Even a small number of streaming replicas are easily managed manually with PostgreSQL-provided tools. However, what happens when we have a large constellation of PostgreSQL servers, such as this?
This diagram represents seven PostgreSQL servers for a single source of data. The Trading server sends its WAL data to a secondary system for safekeeping. One replica subscribes directly to the Trading database, while two others acquire their data through cascading replication. All clones are attached to the WAL archive ...
