Demo: rebuilding a broken projection from the event store
On This Lesson 3 topics
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In this lesson
recover a read model that has wrong data, without downtime.
Draft outline details
Step by step
- Show the symptom: Shop's tracking page shows Delivered shipments as In transit.
- Find the bug in the projection handler and fix it in a new projection version.
- Rebuild into a new table in parallel from position zero, tracking progress.
- Planned mistake: switch readers before the rebuild catches up; fix by comparing positions and counts, then switching with a flag.
- Drop the old table after a soak period and add a rebuild runbook.
Prepares SRB-001-LAB1.
Practice
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