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	2330ms	1122ms	6343ms	5557ms	1145ms
individual writes	226ms	413ms	714ms	828ms	393ms
batch writes	2973ms	1924ms	1131ms	1839ms	2882ms
len()	0ms	0ms	257ms	401ms	64ms
random reads	811ms	580ms	2325ms	1567ms	837ms
random reads	780ms	578ms	2329ms	1550ms	820ms
random range reads	2376ms	1186ms	4512ms	4534ms	1372ms
random range reads	2359ms	1197ms	4448ms	4488ms	1366ms
random reads (4 threads)	329ms	154ms	644ms	479ms	342ms
random reads (8 threads)	173ms	77ms	326ms	255ms	440ms
random reads (16 threads)	109ms	46ms	237ms	165ms	1584ms
random reads (32 threads)	90ms	41ms	180ms	136ms	4686ms
removals	1737ms	795ms	2660ms	2341ms	1138ms
compaction	963ms	N/A	N/A	N/A	N/A
size after bench	311.23 MiB	582.22 MiB	206.39 MiB	454.01 MiB	4.00 GiB

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.