Back-of-the-envelope estimation
On This Lesson 4 topics
This lesson is planned. The outline below lists the topics it will cover. The full lesson has not been published yet.
In this lesson
estimate quickly and show the arithmetic.
Planned topics
- Use round numbers and powers of ten; state units.
- Know typical figures: a request's CPU time, a disk or network throughput, a row's size (verify against your environment).
- Write assumptions first, then arithmetic, then a sanity check against known data.
- The goal is the order of magnitude and the first bottleneck.
Draft outline details
Demonstration
an estimate: 6,000 orders/min peak = 100/s; 25 calls each = 2,500 RPS; at 4 ms CPU each = 10 cores busy; with 50% target utilization, about 20 cores.
Check your understanding
What is the purpose of a back-of-the-envelope estimate?
Show answer
Find order of magnitude and the first bottleneck, with visible assumptions.
Practice
Apply this lesson with the module's lab, exercises and quiz.
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