posthog/ee/benchmarks/README.md

Clickhouse query benchmarks

This is the benchmark suite for PostHog clickhouse queries. It tracks performance improvements to clickhouse queries over time.

The benchmarks are run using airspeed velocity.

To get stable results over time, a stable clickhouse node which has been pre-filled with data is used to run against.

Historical benchmark results can be found in https://github.com/PostHog/benchmark-results.

FAQ

Benchmarking your PRs

Benchmarks run every day against master branch.

If your branch contains significant changes to query performance, add performance label to your PR.

An action will then run and comment on the benchmarks on your PR.

Installation (local)

These benchmarks are run using airspeed velocity so, you need to have asv installed,

pip install asv

Running the benchmarks locally

These benchmarks are mostly run in CI for:

• master branch
• PRs labeled with performance

To run the all the benchmarks locally, get access to the clickhouse node and:

# Set up machine
asv machine --machine ci-benchmarks --config ee/benchmarks/asv.conf.json
# Replace X with appropriate credentials
CLICKHOUSE_HOST=X CLICKHOUSE_USER=X CLICKHOUSE_PASSWORD=X CLICKHOUSE_DATABASE=posthog asv run --config ee/benchmarks/asv.conf.json

See asv documentation for additional information.

Adding new benchmarks

Edit the benchmarks.py file as needed. Use @benchmark_clickhouse decorator to select tests to run

Backfilling benchmarks

• Clone https://github.com/PostHog/benchmark-results locally under ee/benchmarks/results
• Run something like CLICKHOUSE_HOST=X CLICKHOUSE_USER=X CLICKHOUSE_PASSWORD=X CLICKHOUSE_DATABASE=posthog asv run --config ee/benchmarks/asv.conf.json --date-period 4d master~500..
• Run asv publish and commit the changes to benchmark-results repo

If you have questions, use benchmark.yml github action as a guide.