Distributed time-series database from scratch. LSM-tree storage, Raft replication, PromQL queries, streaming anomaly detection.
Understanding distributed systems requires building them. Helios is a from-scratch TSDB that implements LSM-trees, Raft consensus, and PromQL parsing.
Write Path: gRPC → WAL → MemTable → SSTable (LSM) Read Path: PromQL Parser → Query Planner → Storage Engine Replication: Raft consensus (3-node cluster) Compression: Gorilla encoding (timestamps + values) Anomaly: Streaming Z-score with sliding window
| Decision | Choice | Why |
|---|---|---|
| Storage | LSM-tree | Write-optimized for time-series ingestion patterns. |
| Consensus | Raft | Understandable consensus. Implemented from the paper. |
| Query | PromQL subset | Industry standard. Good exercise in parser implementation. |