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Build, the simulations surface — on call when the cache takes down the database

A technical flight simulator for a real on-call incident, worked end to end. At 15:00:00 a hot cache key expires; one second later the page fires — DB CPU pinned at 100%, the connection pool exhausted at 500/500, every request timing out. You read the page before touching anything, find the flaw that was always in the cache-aside read, catch an AI assistant proposing two fixes that would make it worse, rank four recovery actions by blast radius, take the smallest safe one, verify the symptom (not the vibe), make the fix durable with a fleet-wide single-flight lock, and close with the postmortem: the structural fix, the operational rule, the guardrail. Ends on the verified completion certificate. Narrated.

3:272026-08-13Narrated

Chapters

What this demo covers

  • Three lanes: 226 coding · 338 no-code · 107 simulations
  • The page: dashboards, alerts and the incident channel, live
  • Read the page before touching anything
  • The diagnosis: cache-aside with no coalescing
  • The AI proposes two fixes — you catch why both are wrong
  • Four actions ranked by blast radius
  • The smallest safe action: re-warm with single-flight
  • Verify the symptom, not the vibe
  • Durable fix + postmortem — then the certificate