GitLab Knowledge Graph

Overview

The GitLab Knowledge Graph (Orbit) is a Rust service that builds a property graph from GitLab instance data (SDLC metadata and code structure) and exposes it through a JSON-based Cypher-like DSL compiled to ClickHouse SQL. It provides a unified context API for AI systems (via MCP) and human users.

The service indexes two types of data into property graph format:

• SDLC metadata: issues, merge requests, CI pipelines, work items, groups, projects, and other GitLab entities streamed via Siphon CDC from PostgreSQL through NATS into ClickHouse.
• Code: call graphs, definitions, references, and repository metadata fetched from Gitaly and parsed into ClickHouse graph tables.

Architecture

flowchart LR
    GitLab[GitLab Core] -- CDC replication --> DIP[Data Insights Platform]
    GKG -- Git RPC --> GitLab
    DIP -- datalake --> CH[(ClickHouse)]
    CH <-- graph tables --> GKG[Knowledge Graph · Orbit]
    GitLab -. gRPC / AuthZ .-> GKG

    style GitLab fill:#333,color:#fff,stroke:#333
    style DIP fill:#6E49CB,color:#fff,stroke:#6E49CB
    style CH fill:#FFCC00,color:#000,stroke:#FFCC00
    style GKG fill:#FC6D26,color:#fff,stroke:#FC6D26

Design documents

The full design documents now live alongside the code in the knowledge-graph repository:

• Overview and architecture
• Indexing (SDLC and code)
• Querying (graph engine, query language)
• Data model
• Schema management
• Security
• Observability

Resources

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