Data Storage & Retrieval
Turn six requirements into a schema, then survive three change requests that a bad model cannot absorb.
Eight slow queries, one index budget. Spend it where it changes the plan, not where it looks obvious.
Two transactions interleave. Name the anomaly and the lowest isolation level that would have prevented it.
Match a workload to a store. The wrong family costs you a rewrite three requirements later.
Tune R, W and N against a failure schedule. Read a stale value and the round ends.
One partition is taking 80% of the traffic. Reshard it live, without dropping a write.
The other tracks
The machine and the network under every diagram · 5 modules · 23h
Making the second request cheap · 4 modules · 16h
Decoupling two services without losing a message · 5 modules · 21h
From one box to a fleet, without a rewrite · 5 modules · 17h
What happens on the worst day · 5 modules · 18h
The six systems you will actually be asked to draw · 6 modules · 22h
Running the forty-five minutes on purpose · 5 modules · 12h
