# microsoft/bf-tree

Bf-Tree is a modern read-write-optimized concurrent larger-than-memory range index in Rust from MS Research.

Repository: https://github.com/microsoft/bf-tree
Canonical: https://ross.abutalabs.com/products/bf-tree
Language: Rust
License: MIT
License Family: permissive
Last push: 2026-08-19T23:54:11+00:00

## Health v2 (maintenance only)
Score: 60/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 98, release rhythm 35, longevity 18
- inputs: {"age_days": 257, "days_push": 14, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1064, forks 44 (observed 2026-08-28T04:03:26.431019+00:00)

## What it is
Bf-Tree is a read-write-optimized concurrent range index (key-value store) written in Rust, from Microsoft Research, designed to work efficiently with data larger than memory. It is distributed as a Rust crate and supports consistent CPR-style snapshots and recovery.

## Use cases
- embed a fast concurrent key-value index in a Rust application
- store and query data larger than available RAM
- take consistent snapshots of an index and recover from them
- build a storage engine needing read-write optimized range indexing
- replace in-memory maps with a persistent larger-than-memory index

## When to choose
- you need a concurrent range index in Rust with snapshot/recovery support
- your working set exceeds memory but you want cache-friendly performance
- you want a research-backed index from Microsoft Research with an MIT license

## When to avoid
- you need a full standalone database server or SQL queries
- you need a mature production database with rich ecosystem support
- you need a distributed or replicated store

## Facets
- artifact type: library
- maturity: active
- function: database, caching, concurrency
- domain: databases, developer-tools, performance
- platform: rust, windows, cross-platform
- tags: key-value-store, range-index, larger-than-memory, concurrent-index, rust-crate, research-project, snapshots, write-optimized, linux, macos

## Member repositories
- microsoft/bf-tree (main) score 60

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:26.431019+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:56:05.439010+00:00, confidence not recorded.
  - readme: https://github.com/microsoft/bf-tree (fetched 2026-08-28T04:03:26.431019+00:00, sha 38457fb94ddb)
- Data as of 2026-08-30T08:39:29.467469+00:00.