Show HN: Rocky – Rust SQL engine with branches, replay, column lineage

Rocky is a Rust-based control plane for data warehouse pipelines, offering features like branching, column-level lineage, and compile-time safety to ensure data integrity and prevent silent corruption.

The trust system for your data. A Rust-based control plane for warehouse pipelines: branches, replay, column-level lineage, compile-time safety, per-model cost attribution. Keep Databricks or Snowflake. Bring Rocky for the DAG.

# macOS / Linux
curl -fsSL https://raw.githubusercontent.com/rocky-data/rocky/main/engine/install.sh | bash
# Windows (PowerShell)
irm https://raw.githubusercontent.com/rocky-data/rocky/main/engine/install.ps1 | iex

rocky playground my-first-project
cd my-first-project
rocky compile && rocky test && rocky run

No credentials needed — the playground runs end-to-end on local DuckDB.

Each demo below is a self-contained POC in examples/playground/pocs/ — cd in, run ./run.sh, reproduce locally.

Automatic Schema Evolution

A source column type changes upstream. On the next run, Rocky diffs source vs. target, drops the target, and recreates it. No silent data corruption, no dbt-style quiet divergence.

Compile-time Safety

Missing required columns, protected columns being removed, or unsafe type changes surface as diagnostic codes (E010, E013) before a single row is written.

Branching

Create a branch, run against it in an isolated schema, inspect, then drop or promote. Column-level lineage shows the downstream blast radius before you ship.

Column-level Lineage

Trace a single column from a downstream fact back through its aggregations, all the way to the seed. Blast-radius analysis without reading every model.

AI-Assisted Modeling

Describe what you want in plain English. Rocky generates a Rocky DSL model, compiles it, and retries on parse failure — the Attempts: 2 line shows the loop catching a first-pass error invisibly.

| Path | Artifact | Language | Description | |---|---|---|---| | engine/ | rocky CLI binary | Rust | Core SQL transformation engine — 20-crate Cargo workspace | | integrations/dagster/ | dagster-rocky PyPI wheel | Python | Dagster resource and component wrapping the Rocky CLI | | editors/vscode/ | Rocky VSIX | TypeScript | VS Code extension — LSP client + commands for AI features | | examples/playground/ | (config only) | TOML / SQL | Self-contained DuckDB sample pipeline used for smoke tests and benchmarks |

Each subproject has its own README with detailed usage. The engine/README.md is the canonical product reference for the Rocky CLI.

git clone https://github.com/rocky-data/rocky.git
cd rocky
just build # builds engine + dagster wheel + vscode extension
just test # runs all test suites
just lint # cargo clippy/fmt + ruff + eslint

just is optional — you can also build each subproject directly. See CONTRIBUTING.md for per-subproject build commands.

Each artifact is released independently using a tag-namespaced scheme: