React-native-lmdb NPM

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).