A prolly tree is similar to a B+ tree, but its node boundaries are determined by the data rather than by insertion order. Each node is addressed by the hash of its contents, and updates create a new root while sharing unchanged nodes with older versions.
This makes it useful when an application needs more than basic key/value storage: cheap snapshots, efficient diffs, three-way merges, deduplication, and incremental sync between replicas.
Some use cases I’m exploring include local-first applications, versioned database indexes, Git-like filesystem snapshots, agent memory and event logs, and reproducible RAG indexes where the exact data snapshot used for an answer can be recorded.
It’s a storage primitive rather than a complete database. The goal is to provide the ordered-map layer and let applications choose their own storage backend, data model, and conflict policy.
The project is still evolving, and I’d appreciate feedback—especially about real-world use cases, the API, and what is missing.
lifty 2 hours ago [-]
Great primitive, I’m a big fan of prolly trees! You mentioned git like filesystem snapshots? How would you retrofit that on an existing filesystem? Or you’re talking about writing a new one?
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A prolly tree is similar to a B+ tree, but its node boundaries are determined by the data rather than by insertion order. Each node is addressed by the hash of its contents, and updates create a new root while sharing unchanged nodes with older versions.
This makes it useful when an application needs more than basic key/value storage: cheap snapshots, efficient diffs, three-way merges, deduplication, and incremental sync between replicas.
Some use cases I’m exploring include local-first applications, versioned database indexes, Git-like filesystem snapshots, agent memory and event logs, and reproducible RAG indexes where the exact data snapshot used for an answer can be recorded.
It’s a storage primitive rather than a complete database. The goal is to provide the ordered-map layer and let applications choose their own storage backend, data model, and conflict policy.
The project is still evolving, and I’d appreciate feedback—especially about real-world use cases, the API, and what is missing.