Distributed
← Caching

Lesson 04.5

Negative caching

Negative caching stores a short-lived not-found result so repeated lookups for an absent key do not bypass the cache and hit the database every time.

🍪 The fast copy can be wrong

Ava and Ben are workers using the computer to manage order. The fast copy remembers things it found, but it also needs to remember “not here” for a little while.

In this lesson you'll

  1. 1Watch the fast copy answer a request
  2. 2Guess where the unsafe gap appears
  3. 3Change the rule and protect the source of truth