Paths/Backend Engineer/Caching & Performance / Invalidation & Measurement
Measure the Hit Ratio
A cache earns its keep with a hit ratio and a latency budget. Write the measurement plan and the objective you will hold it to.
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01Requirements
live checks- File ~/backend/cache/metrics.md exists○
- The document defines the hit ratio○
- The document states the objective and the latency budget○
- The document names the metric that is watched○
02Walkthrough
1 of 4 revealed- 01
Define the metric
hit ratio is hits divided by hits plus misses. Count both, and the ratio follows.
echo '# Cache metrics\n\n## Hit ratio\n\nhit ratio = hits / (hits + misses), counted per namespace.' > ~/backend/cache/metrics.md - 3 locked · each failed submit reveals one
03Stuck?
0 of 3 revealedTake a hint without losing the lab — each one points at the thing to look at, not at the answer.
04AI Tutor
guides, never solvesTell me what you're stuck on — I'll nudge, not solve. Which requirement are you looking at?
04Notebook
saved locally in this browserlearner@lab — ubuntu:24.04
Session is disposable
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