VarveDB

Embedded append-only event store for Rust, built on LMDB (heed) and rkyv. Designed for event sourcing and audit logs: zero-copy reads, predictable write throughput, no external services.

How it works

Events go into three LMDB-backed structures:

• Global log — append-only, ordered by global sequence number
• Stream index — per-stream lookups without scanning the global log
• Stream metadata — tracks sequence heads per stream

Writes are sequential. Reads are zero-copy via rkyv (no deserialization). ACID transactions and crash safety come from LMDB.

Numbers

Benchmarks on a MacBook Pro M2 + NVMe:

Operation	Throughput	Latency
Batch write	~1.02M events/sec	~978 ns/event
Sequential read	~2.28M events/sec	~438 ns/event
Stream iteration	~2.92M events/sec	~342 ns/event

Under active development. APIs may change before 1.0.