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kiwi-db

A production-grade Log-Structured Merge Tree key-value store written in Python 3.12+.

Features

  • Async-first API — put, get, delete, flush, close are all async
  • Write-ahead log — crash recovery via WAL replay
  • Concurrent skip-list memtable — fine-grained locking for concurrent writes
  • SSTable persistence — bloom filters, sparse indexes, memory-mapped reads
  • Tiered compaction — L0 → L1 → L2 → L3 with subprocess-based merging
  • Runtime configuration — update thresholds without restarting

Quick Start

pip install .        # or: uv pip install -e .
kiwi-db repl         # interactive REPL
kiwi-db api          # REST API server on :8081
kiwi-db web          # full web dashboard with React frontend

As a Library

from app.engine import LSMEngine

engine = await LSMEngine.open("./data")

await engine.put(b"hello", b"world")
value = await engine.get(b"hello")    # b"world"
await engine.delete(b"hello")

await engine.close()

Documentation