Demo: shadow-reading shipment status from both systems
On This Lesson 3 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
run a shadow read of shipment status comparing old and new systems; prepares SRB-017-LAB1.
Draft outline details
Step by step
- Define the comparison key, fields to compare, and the mismatch threshold for cut-over.
- Route a copy of read requests to the new path behind a flag; log both results.
- Review the mismatch report by category after a day of traffic.
- Planned mistake: treat a timing difference as a bug and chase it. Fix: classify expected differences (event delay) and compare after a settle window.
- Fix a real mismatch (status mapping) and watch the rate fall below the threshold.
- Record the decision: ready for 5% serving, with a rollback via flag.
Check your understanding
What must be defined before shadow reads begin?
Show answer
The comparison fields and the mismatch threshold.
Practice
Apply this lesson with the module's lab, exercises and quiz.
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