Asked about The classic fundamentals
What is a cache stampede and how do you prevent it?
An answer that works
Many requests miss the same key simultaneously and all recompute the expensive value at once. Prevent it with a lock so only one recomputes while the others wait, or by staggering expiry times so keys do not all expire together.
Reading an answer is not being able to give one. The section that teaches this is The classic fundamentals, 6 hours of Distributed systems.
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