Replication yana kwafagi data daga babbar primary database zuwa ɗaya ko da yawa replica (standby) servers — don high availability (failover idan primary ya kaddaci) da read scaling (rarraba read queries). PostgreSQL galibi yana amfani da streaming replication (physical) dangane da write-ahead log (WAL).
Streaming (physical) replication
Primary ──(streams WAL: the write-ahead log of changes)──▶ Replica(s)
✓ The primary handles all WRITES
✓ Replicas continuously apply the primary's WAL → stay in sync (near-real-time)
✓ Replicas can serve READ queries ("hot standby") → scale reads
