lsm-tree 3.0.0-pre.0

A K.I.S.S. implementation of log-structured merge trees (LSM-trees/LSMTs) in Rust.

[!NOTE] This crate only provides a primitive LSM-tree, not a full storage engine. For example, it does not ship with a write-ahead log. You probably want to use https://github.com/fjall-rs/fjall instead.

About

This is the most feature-rich LSM-tree implementation in Rust! It features:

Thread-safe BTreeMap-like API
Mostly safe & 100% stable Rust
Block-based tables with compression support & prefix truncation
- Optional block hash indexes in data blocks for faster point lookups [3]
- Per-level filter/index block pinning configuration
Range & prefix searching with forward and reverse iteration
Block caching to keep hot data in memory
File descriptor caching with upper bound to reduce fopen calls
AMQ filters (currently Bloom filters) to improve point lookup performance
Multi-versioning of KVs, enabling snapshot reads
Optionally partitioned block index & filters for better cache efficiency [1]
Size-tiered, (concurrent) Leveled and FIFO compaction
Multi-threaded flushing (immutable/sealed memtables)
Key-value separation (optional) [2]
Single deletion tombstones ("weak" deletion)

Keys are limited to 65536 bytes, values are limited to 2^32 bytes. As is normal with any kind of storage engine, larger keys and values have a bigger performance impact.