ClickCannon is a newly open-sourced benchmarking tool for ClickHouse, originally built internally to size observability workloads for ClickStack. It supports replaying real OpenTelemetry data at controlled throughput, simulating concurrent users with realistic query patterns, and collecting detailed performance metrics. The tool uses a Go-based pipeline with decoupled disk and insert workers, a token-bucket speed limiter, block pooling with retirement logic to prevent memory growth, and pre-flight parameterized queries for realistic user simulation. Metrics are flushed to a separate ClickHouse instance and visualized via Grafana, with Claude and the ClickHouse MCP server used for analysis. Synthetic data generation is also supported for edge-case workloads. The tool is available on GitHub.
