Scaling and Performance

What is inside

Every section, and every one of them opens in the browser. Nothing here is hidden: if a section you need is not in this list, the notebook is not the right one and you should not spend a week on it.

1. How to use this book
2. 1"Slow" is not a bug report
3. 2Latency is a distribution, not a number
4. 3Why P99 is your most valuable customers
5. 4Throughput, and the curve that bends
6. 5Utilization and the knee
7. 6Headroom, and why traffic arrives in bursts
8. 7Never guess. The week spent on the wrong fix
9. 8Profiling, and what a flame graph shows
10. 9Distributed tracing, and why waiting needs it
11. 10What to measure, in what order
12. 11N+1: the shape, not the name
13. 12Indexes: the catalogue, the tree, and the cost
14. 13Composite and covering indexes
15. 14EXPLAIN ANALYZE: deciding instead of guessing
16. 15Connections are not free
17. 16Pooling, and the autoscaler that killed the database
18. 17What caching actually buys
19. 18Invalidation: the second hard problem
20. 19Where the cache lives
21. 20Three patterns: aside, through, behind
22. 21Hit rate, and the four things that move it
23. 22Vertical scaling, and its three ceilings
24. 23Horizontal scaling, and the bill it comes with
25. 24Statelessness is the price of admission
26. 25The load balancer, and five algorithms
27. 26Health checks, and the server that is up but dead
28. 27Read replicas
29. 28Replication lag, and the read-after-write bug
30. 29Sharding, and the key that is hard to choose
31. 30Distributed databases: rent, do not build
32. 31The speed of light, and the latency budget
33. 32CDNs: what goes on one
34. 33The edge, and what it cannot do
35. 34Asynchronous processing: the queue as a latency tool
36. 35What can be made async, and what cannot
37. 36Microservices scale teams, not machines
38. 37What a network boundary costs
39. 38Serverless: the pricing model is the point
40. 39Cold starts, limits, and statelessness
41. 40When serverless fits, and when it does not
42. 41How to answer "how would you scale this?"
43. 42Five traps
44. 43The five rules
45. Appendix A. Numbers worth memorising
46. Appendix B. Glossary
47. Appendix C. Final review

How to read it

Read with a pen. Every notebook opens with a question to answer before you start and asks you to redo the answer at the end, and the margin in the Print edition exists so you have somewhere to be wrong first. The Tablet edition is 16:9 with vector text, so note apps draw on it rather than treating it as a photograph.