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Running production: reliability, observability, performance and security · Proficient · Lesson 74 of 98 · 50 min video, then about 8 hours of practice
Finding and fixing performance problems
After this you can measure a slow path, find the bottleneck with a profiler, query plan or trace, fix it, and prove the improvement with numbers.
Why it matters
Performance work without measurement is guessing. Measure first: load test to reproduce the problem, profile to see where time goes (flame graphs), read query plans for slow database calls, and check traces for slow downstream calls. Then fix the biggest thing and measure again. Most real-world web performance problems are database queries (missing indexes, N+1), unbounded work in a request, or chatty network calls. Trap: optimising the code you suspect rather than the code the profiler shows.
How to use this resource
The inventor of flame graphs on how to read them. Essential for any profiling.