Physical Replication (Streaming)

Physical replication in PostgreSQL creates an exact, byte-for-byte copy of your primary database server. Think of it as mirroring the entire data directory and all changes that happen.

This method is highly robust for disaster recovery and provides a consistent read-only copy of your data, known as a standby server. If your primary server fails, you can promote the standby to become the new primary.

Streaming replication is a form of physical replication where the primary server continuously sends its Write-Ahead Log (WAL) records to the standby server. The standby then applies these WAL records in real-time.

This ensures the standby is always up-to-date with the primary, minimizing data loss in case of a failure. It's like a constant stream of updates flowing from one database to another.