Memory RxStorage

The Memory RxStorage is based on plain in-memory arrays and objects. It can be used in all environments and is made for performance. By storing data directly in RAM, it eliminates disk I/O bottlenecks and operates faster than traditional disk-based databases.

You should use this storage when you need a fast database configuration, such as in unit tests, server-side rendering, or high-throughput data processing.

How it achieves maximum speed

• No Disk I/O: Operations happen entirely in RAM. There is no waiting for disk reads or writes.
• No Serialization Overhead: Data remains as JavaScript objects and arrays. It skips the expensive JSON serialization and deserialization steps required by index-based or file-based storages.
• Binary Search: It uses pure JavaScript arrays and binary search algorithms on all database operations, ensuring fast queries and index traversals.
• Small Build Size: The plugin contains minimal code, keeping your bundle size small.

Use Cases

1. Unit Testing and CI/CD

The Memory storage is the recommended storage for testing RxDB applications. It provides two major benefits: speed and isolation. Because it keeps data only in memory, each test run can start with a clean state without needing to clean up leftover filesystem states or deleting IndexedDB databases.

You can also simulate multi-tab behavior inside a single Node.js process by creating multiple RxDatabase instances with the same name and the ignoreDuplicate: true setting. They will share the memory state and communicate with each other naturally.

2. Server-Side Rendering (SSR)

When rendering React, Vue, or Angular applications on the server, you often need to fetch data, populate a database state, and render the UI. Using the Memory storage ensures your server handles these requests quickly without touching the file system, reducing latency and avoiding disk write locks.

3. Caching and Real-Time Processing

For applications handling thousands of events per second, such as real-time analytics dashboards or temporary chat state, the Memory storage acts as a fast data layer. You achieve instantaneous data access for aggregations and queries.

4. Memory-Mapped Performance Upgrades

RxDB provides a Memory-Mapped RxStorage which uses the Memory storage as a fast, primary layer and replicates data to a slower persistence storage in the background. This improves initial page load and query times while still keeping data safe on disk.

Implementation

import {
    createRxDatabase
} from 'rxdb';
import {
    getRxStorageMemory
} from 'rxdb/plugins/storage-memory';
 
const db = await createRxDatabase({
    name: 'exampledb',
    storage: getRxStorageMemory()
});

Constraints

• No Persistence: All data is lost when the JavaScript process exits or the browser tab is closed.
• Memory Limits: The dataset is constrained by the available RAM in the JavaScript runtime environment.