Chapter 10

1. If you are using binary replication, the master and slave have to use the same major release of PostgreSQL. In other words, you cannot use streaming to upgrade from, say, PostgreSQL 10 to PostgreSQL 11 using a transaction log stream. Logical replication can help to bridge this gap. In addition to that, logical replication can help selectively replicate data to various systems.
2. Synchronous replication will be slower than binary replication. In general, the performance impact of short transactions will be a lot greater than for long transactions. It is hard to state a precise number as the performance decrease depends significantly on network latency. The slower your network, the slower your synchronous replication is.
3. Try to use synchronous replication only when it is absolutely necessary to reduce the impact on speed and availability. In most cases, asynchronous...