Download
Hitchhiker-Tree is a functional, immutable, off-heap, snapshottable sorted map data structure (a persistent key-value tree) designed for scalable, high-performance storage in Clojure / ClojureScript systems. It blends ideas from fractal trees and B-trees, supports lazy loading, and can persist incrementally to arbitrary backends. It is used as a backend for systems like Datahike and can support enormous data sets while retaining functional persistence semantics. Outboard is a simple API for your Clojure applications that enables you to make use of tens of gigabytes of local memory, far beyond what the JVM can manage. Outboard also allows you to restart your application and reuse all of that in-memory data, which dramatic reduces startup times due to data loading.
Features
- Immutable (persistent) data structure; modifications yield new versions without mutating old ones
- Off-heap backing: can store data outside the JVM heap so as to reduce GC pressure
- Snapshottable: supports creating consistent snapshots for reads or forks
- Lazy loading from backing stores; only the needed nodes/pages are loaded into memory
- Backend-agnostic persistence: can plug into filesystem, Redis, KV stores, etc. via protocol adapters
- Benchmarking suite with parameter explorations (branching factor, deletion reorder etc.)
Project Samples
