One of the things that my students and clients most ask for in PostgreSQL is multi-master replication. That is, they’re OK with the existing master-slave replication, in which one server handles both reads and writes, and the others (slaves) are read-only.   In this talk, PostgreSQL core developer Andres Freund describes a number of different master-master solutions that have been proposed and implemented over the years, and describes a project on which he’s working that he hopes (and expects) will pave the way forward for multi-master replication in the coming years.