Replication Lag Calculator
Estimate database replication lag in milliseconds and data volume behind the primary. Plan for eventual consistency in read replica architectures.
How to Use the Replication Lag Calculator
- Enter write operations per second.
- Enter average row size in bytes.
- Enter network latency in ms.
- Enter available bandwidth in Mbps.
- Click Calculate to get estimated lag.
حالات الاستخدام
- •Designing read replica architectures for scalability.
- •Evaluating synchronous vs asynchronous replication tradeoffs.
- •Planning disaster recovery RPO requirements.
- •Diagnosing replication lag in production databases.
الصيغة
Transmit time = throughput (bytes/s) / bandwidth (bytes/s) × 1000 ms. Lag = network latency + transmit time.
الأسئلة الشائعة
What causes replication lag?
High write throughput, slow network, large transaction sizes, and single-threaded replay can all cause lag.
How much lag is acceptable?
For most applications, under 100ms is acceptable. Real-time reporting may require near-zero lag using synchronous replication.
How do I monitor replication lag?
Use pg_stat_replication (PostgreSQL), SHOW SLAVE STATUS (MySQL), or cloud provider metrics like AWS RDS ReplicaLag.