Replication

Replication copies data or change streams from one database instance to others for read scaling, high availability, or analytics.

Common axes:

• Synchronous vs asynchronous: does the primary wait for a replica before acknowledging a commit?
• Physical vs logical: byte-for-byte copy of storage vs row-level change events for subsets or pipelines.

Replicas may lag; applications must decide whether stale reads are acceptable.

For PostgreSQL streaming replication and logical replication patterns, see Postgres replication.