Event Replay and Reprojection¶
Rebuild a derived view from an immutable event log without disrupting the live view.
flowchart LR J[Junior: why replay] --> M[Middle: rebuild mechanics] --> S[Senior: replay failures] --> P[Professional: billion-event scale]flowchart LR Log[(Event log)] --> Old[Live projection] Log --> New[Rebuilt projection] --> Cutover| Level | Guide | You are done when | |---|---|---| | Junior | Definition and why | You can explain projection rebuilds. | | Middle | How it works | You can replay, catch up, and cut over. | | Senior | Failures and mistakes | You can prevent duplicates and stale cutover. | | Professional | Best practices and scale | You can operate large online rebuilds. | Practice rule: Build beside the live view; never destroy the only serving copy first.