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	2689ms	1247ms	5330ms	5892ms	1187ms
individual writes	226ms	419ms	703ms	816ms	398ms
batch writes	2522ms	2070ms	1047ms	1867ms	2776ms
len()	0ms	0ms	304ms	444ms	64ms
random reads	860ms	624ms	2432ms	1596ms	875ms
random reads	866ms	624ms	2464ms	1588ms	842ms
random range reads	2347ms	1179ms	4436ms	4907ms	1367ms
random range reads	2322ms	1207ms	4465ms	4732ms	1373ms
random reads (4 threads)	337ms	158ms	732ms	488ms	349ms
random reads (8 threads)	185ms	81ms	433ms	259ms	277ms
random reads (16 threads)	116ms	49ms	238ms	165ms	1708ms
random reads (32 threads)	100ms	44ms	203ms	142ms	4714ms
removals	1889ms	803ms	2038ms	2371ms	1170ms
uncompacted size	1.00 GiB	582.22 MiB	206.38 MiB	457.01 MiB	4.00 GiB
compacted size	311.23 MiB	284.46 MiB	106.26 MiB	N/A	N/A

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.