Definition
A copy of the database that serves reads, taking load off the primary which handles writes.
How it works
The standard way to scale reads on a SQL database: the primary streams its changes to replicas, and you route SELECTs there. Cheap and effective, but replicas lag, so a read right after a write may be stale (read-your-writes anomaly). It scales reads, not writes — write scaling needs sharding.
Common questions
What is Read Replica?
A copy of the database that serves reads, taking load off the primary which handles writes.
How does Read Replica work?
The standard way to scale reads on a SQL database: the primary streams its changes to replicas, and you route SELECTs there. Cheap and effective, but replicas lag, so a read right after a write may be stale (read-your-writes anomaly). It scales reads, not writes — write scaling…
What is Read Replica used for in system design?
The standard way to scale reads on a SQL database: the primary streams its changes to replicas, and you route SELECTs there. Cheap and effective, but replicas lag, so a read right after a write may be stale (read-your-writes anomaly). It scales reads, not writes — write scaling…