Sharding RxStorage

With the sharding plugin, you can improve the write and query times of some RxStorage implementations. For example on slow IndexedDB, a performance gain of 30-50% on reads, and 25% on writes can be achieved by using multiple IndexedDB Stores instead of putting all documents into the same store.

The sharding plugin works as a wrapper around any other RxStorage. The sharding plugin will automatically create multiple shards per storage instance and it will merge and split read and write calls to it.

Premium

The sharding plugin is part of RxDB Premium 👑. It is not part of the default RxDB module.

Using the sharding plugin

import {
    getRxStorageSharding
} from 'rxdb-premium/plugins/storage-sharding';

import { getRxStorageDexie } from 'rxdb/plugins/storage-dexie';


/**
 * First wrap the original RxStorage with the sharding RxStorage.
 */
const shardedRxStorage = getRxStorageSharding({

    /**
     * Here we use the dexie.js RxStorage,
     * it is also possible to use any other RxStorage instead.
     */
    storage: getRxStorageDexie()
});


/**
 * Add the sharding options to your schema.
 * Changing these options will require a data migration.
 */
const mySchema = {
    /* ... */
    sharding: {
        /**
         * Amount of shards per RxStorage instance.
         * Depending on your data size and query patterns, the optimal shard amount may differ.
         * Do a performance test to optimize that value.
         * 10 Shards is a good value to start with.
         * 
         * IMPORTANT: Changing the value of shards is not possible on a already existing database state,
         * you will loose access to  your data.
         */
        shards: 10,
        /**
         * Sharding mode,
         * you can either shard by collection or by database.
         * For most cases you should use 'collection' which will shard on the collection level.
         * For example with the IndexedDB RxStorage, it will then create multiple stores per IndexedDB database
         * and not multiple IndexedDB databases, which would be slower.
         */
        mode: 'collection'
    }
    /* ... */
}


/**
 * Create the RxDatabase with the wrapped RxStorage. 
 */
const database = await createRxDatabase({
    name: 'mydatabase',
    storage: shardedRxStorage
});