Go Prod Info Log Bench
This repository contains tests to illustrate the performance costs of INFO and DEBUG logs in environments where the log level is set to WARN.
tl;dr - Avoid info logging WithFields in the hot path of performance sensitive applications.
I was reluctant to adopt Zap for a long time because... Log performance shouldn't matter.
If your app is writing so many logs in production that logging is a bottleneck, you've got bigger problems.
What is of concern to me is the performance cost of ignored logs in production.
What happens when production code encounters a statement like
Production environments use log levels to ignore info and debug statements, but that log statement must still be evaluated.
$ go test -bench=. -benchmem BenchmarkZapInfo-12 41377027 28.3 ns/op 0 B/op 0 allocs/op BenchmarkZapSugarInfo-12 100000000 11.5 ns/op 0 B/op 0 allocs/op BenchmarkLogrusInfo-12 249465934 4.81 ns/op 0 B/op 0 allocs/op BenchmarkZapInfoWithFields-12 11537806 104 ns/op 128 B/op 1 allocs/op BenchmarkZapSugarInfoWithFields-12 24488396 47.0 ns/op 16 B/op 1 allocs/op BenchmarkLogrusInfoWithFields-12 2154274 558 ns/op 512 B/op 5 allocs/op BenchmarkZapWarn-12 1308540 919 ns/op 216 B/op 2 allocs/op BenchmarkZapSugarWarn-12 999940 1210 ns/op 248 B/op 3 allocs/op BenchmarkLogrusWarn-12 499970 2406 ns/op 480 B/op 15 allocs/op BenchmarkZapSugarWarnWithFields-12 857092 1439 ns/op 280 B/op 4 allocs/op BenchmarkZapWarnWithFields-12 857092 1393 ns/op 344 B/op 3 allocs/op BenchmarkLogrusWarnWithFields-12 333314 3492 ns/op 1009 B/op 21 allocs/op PASS ok github.com/main 16.594s
Some interesting things:
- Logrus is the most performant for ignored static info logging
- Zap sugar is more performant than regular zap for ignored WithFields info logs in prod ¯\_(?)_/¯
- Ignored WithFields info logging can cost 0.1 - 0.5 microseconds in production
- Info and Debug logging is not free in production.
- Avoid info logging WithFields in the hot path of performance sensitive applications.
Have a nice day.