Logical decoding can be used to build
synchronous
replication solutions with the same user interface as synchronous
replication for streaming
replication. To do this, the streaming replication interface
(see Section 49.3) must be used to stream out
data. Clients have to send Standby status update (F)
(see Section 53.4) messages, just like streaming
replication clients do.
A synchronous replica receiving changes via logical decoding will work in
the scope of a single database. Since, in contrast to
that, synchronous_standby_names currently is
server wide, this means this technique will not work properly if more
than one database is actively used.