DatabasesIntermediate
Primary / Replica
PronunciationPRY-ma-ree / REP-li-kuh
Definition
A database architecture pattern where all write operations go to a single primary node, and data is copied to one or more replica nodes that handle read operations to improve performance and availability.
Where you hear it
- Scaling database reads - High availability planning - Database replication configuration
Examples
We configured the application to send heavy read queries to the replica.
When the primary node failed, one of the replicas was promoted to take its place.
Common mistake
Assuming that replicas receive data updates instantly, leading to unexpected stale reads if the application reads data immediately after writing it.