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#2 in Database implementations

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27,567 downloads per month
Used in 59 crates (40 directly)

MIT/Apache

605KB
15K SLoC

redb

CI Crates.io Documentation License dependency status

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

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.

Dependencies

~0–6MB
~15K SLoC