Lesson 3: A cache in front of BrightCart's slow lookups

Module 11 · Lesson 3 · About 40 minutes · Needs: Lesson 1 (tables and queries), Module 4 (embeddings), Module 7 Lesson 5 (the exact-match cache)

The situation

Dev shows you the logs. "Where is my order?" is BrightCart's most common message, and each one runs the same database query. Aisha Rahman asked about order 5521 four times yesterday. "Can I return my vacuum?" arrives dozens of times a day, each one a paid model call.

Dev wants a cache: a fast store that keeps copies of answers so slow work is not repeated. Priya has one condition: a customer must never see an old status, or someone else's data. This lesson builds the cache and shows where both worries come true.