influxdb/ingester2/benches/README.md

## `ingester2` benchmarks

Run them like this:

```console
% cargo bench -p ingester2 --features=benches
```

This is required to mark internal types as `pub`, allowing the benchmarks to
drive them.
test(ingester2): WAL replay benchmark This adds a simple WAL replay benchmark to ingester2 that executes a replay of a single line of LP. Unfortunately each file in the benches directory is compiled as it's own binary/crate, and as such is restricted to importing only "pub" types. This sucks, as it requires you to either benchmark at a high level (macro, not microbenchmarks - i.e. benchmarking the ingester startup, not just the WAL replay) or you are forced to mark the reliant types & functions as "pub", as well as all the other types/traits they reference in their signatures. Because the performance sensitive code is usually towards the lower end of the call stack, this can quickly lead to an explosion of "pub" types causing a large amount of internal code to be exported. Instead this commit uses a middle-ground; benchmarked types & fns are conditionally marked as "pub" iff the "benches" feature is enabled. This prevents them from being visible by default, but allows the benchmark function to call them. The benchmark itself is also restricted to only run when this feature is enabled. 2022-12-12 13:24:11 +00:00			## `ingester2` benchmarks

			`Run them like this:`

			```console
			`% cargo bench -p ingester2 --features=benches`
			```

			This is required to mark internal types as `pub`, allowing the benchmarks to
			`drive them.`