redb

A simple, portable, high-performance, ACID, embedded key-value store.

redb is written in pure Rust and is loosely inspired by lmdb. Data is stored in a collection of copy-on-write B-trees. For more details, see the design doc

use redb::{Database, Error, ReadableTable, TableDefinition};

const TABLE: TableDefinition<&str, u64> = TableDefinition::new("my_data");

fn main() -> Result<(), Error> {
    let db = Database::create("my_db.redb")?;
    let write_txn = db.begin_write()?;
    {
        let mut table = write_txn.open_table(TABLE)?;
        table.insert("my_key", &123)?;
    }
    write_txn.commit()?;

    let read_txn = db.begin_read()?;
    let table = read_txn.open_table(TABLE)?;
    assert_eq!(table.get("my_key")?.unwrap().value(), 123);

    Ok(())
}

Status

redb is undergoing active development, and should be considered beta quality. The file format is stable, but redb has not been widely deployed in production systems (at least to my knowledge).

Features

• Zero-copy, thread-safe, BTreeMap based API
• Fully ACID-compliant transactions
• MVCC support for concurrent readers & writer, without blocking
• Crash-safe by default
• Savepoints and rollbacks

Development

To run all the tests and benchmarks a few extra dependencies are required:

• cargo install cargo-deny --locked
• cargo install cargo-fuzz --locked
• apt install libclang-dev

Benchmarks

redb has similar performance to other top embedded key-value stores such as lmdb and rocksdb

	redb	lmdb	rocksdb	sled	sanakirja
bulk load	2792ms	1115ms	5610ms	5005ms	1161ms
individual writes	462ms	1119ms	1097ms	957ms	662ms
batch writes	2568ms	2247ms	1344ms	1622ms	2713ms
random reads	988ms	558ms	3469ms	1509ms	678ms
random reads	962ms	556ms	3377ms	1425ms	671ms
random range reads	2534ms	985ms	6058ms	4670ms	1089ms
random range reads	2493ms	998ms	5801ms	4665ms	1119ms
random reads (4 threads)	344ms	141ms	1247ms	424ms	266ms
random reads (8 threads)	192ms	72ms	673ms	230ms	620ms
random reads (16 threads)	131ms	47ms	476ms	148ms	3500ms
random reads (32 threads)	118ms	44ms	412ms	129ms	4313ms
removals	2184ms	784ms	2451ms	2047ms	1344ms

Source code for benchmark here. Results collected on a Ryzen 5900X with Samsung 980 PRO NVMe.

License

Licensed under either of

• Apache License, Version 2.0
• MIT License

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.