Read replicas and lag-aware design
On This Lesson 4 topics
This lesson is planned. The outline below lists the topics it will cover. The full lesson has not been published yet.
In this lesson
use replicas without breaking correctness.
Planned topics
- Replicas serve reads asynchronously; they lag behind the primary.
- Reads that must see just-written data (read-your-writes) go to the primary or use session stickiness or LSN checks.
- Monitor replica lag and fall back to the primary above a threshold.
- Replicas help read scaling and failover, not write scaling.
Draft outline details
Demonstration
a routing rule: after a customer's write, read from the primary for N seconds, else a replica.
Check your understanding
What do replicas not scale?
Show answer
Writes.
Practice
Apply this lesson with the module's lab, exercises and quiz.
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