react-native-lmdb

react-native-lmdb

LMDB (Lightning Memory-Mapped Database) is an embedded transactional database in the form of a key-value store. It can handle vast amounts of data and is comparable in speed to MMKV.

This package embeds & provides React Native bindings for LMDB.

Installation

npm install react-native-lmdb
cd ios && pod install

Usage

import { open } from 'react-native-lmdb';

// Define the largest size of the db (100mb in this case)
const mapSize = 1024 * 1024 * 100;

const { put, get, del } = open('mydb.mdb', mapSize);

put('key1', 'value1');
put('key2', 'value2');

console.log(get('key1'));
console.log(get('key2'));

del('key1');
del('key2');

Motivation

MMKV is a great tool but isn't designed for vast amounts of data.

When setting and getting 10_000 large strings:

DB	Empty	Run 1	Run 2	Run 3
mmkv	16kb	33.6mb	67.1mb	67.1mb
lmdb	33kb	38.3mb	38.3mb	38.3mb

// @TODO - check db sizes on devices

SQLite can handle vast amounts of data but is async thus increases complexity and introduces possible race conditions.

LMDB is mature, synchronous, and can handle anything you throw at it. 💪

Goals of this Project

• Simple API
• Performance over features

Benchmarks

NOTES: these numbers might not represent current state. I am still in the process of profiling and optimising.

iOS (Simulator) react-native-lmdb react-native-mmkv put 10_000 42038.66ms 1815.24ms put 10_000 (txn) 1512.22ms n/a get 10_000 33.74ms 57.98ms db size run 1 db size run 2 db size run 3

iOS (iPhone 7) react-native-lmdb react-native-mmkv put 10_000 42038.66ms 1815.24ms put 10_000 (txn) 1512.22ms n/a get 10_000 33.74ms 57.98ms db size run 1 db size run 2 db size run 3

Android (Emulator) react-native-lmdb react-native-mmkv put 10_000 1769.53ms 117.94ms put 10_000 (txn) 288.43ms n/a get 10_000 26.74ms 16.29ms db size run 1 db size run 2 db size run 3

Android (Pixel 6a) react-native-lmdb react-native-mmkv put 10_000 1769.53ms 117.94ms put 10_000 (txn) 288.43ms n/a get 10_000 26.74ms 16.29ms db size run 1 db size run 2 db size run 3

We can conclude:

• mmkv is fast to read
• mmkv is fast to write
• lmdb to fast to read
• lmdb is (potentially very) slow to write depending on device, but can write fast when using a transaction (txn).

Credits

• Thanks to sysmas for open sourcing lmdb.
• Thanks to drycpp/lmdb++ & hoytech/lmdb++ for the useful c++ wrapper.

Donate

If you find LMDB useful please consider supporting the OpenLDAP foundation: https://www.openldap.org/foundation/

Contributing

See the contributing guide to learn how to contribute to the repository and the development workflow.

License

MIT

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Made with create-react-native-library