MongoDB vs RethinkDB: What are the differences?

Introduction

MongoDB and RethinkDB are both NoSQL databases, but they have some key differences that set them apart.

1. Data Replication and Sharding: MongoDB uses replication to provide data redundancy and fault tolerance, while RethinkDB uses a process called automatic sharding. MongoDB's replication ensures that data is copied to multiple servers, providing high availability and durability. On the other hand, RethinkDB's automatic sharding splits data across multiple servers, enabling horizontal scalability.

2. Real-time Push Architecture: RethinkDB has a built-in real-time push architecture, which allows developers to subscribe to changes in the database and receive updates instantly. This is particularly useful for applications that require real-time updates, such as chat applications or collaborative tools. MongoDB does not have a native real-time push architecture and requires additional tools or libraries to achieve similar functionality.

3. Query Language: MongoDB uses a query language called MongoDB Query Language (MQL), which is a flexible and powerful language for querying and manipulating data. RethinkDB, on the other hand, uses its own query language called ReQL, which is designed to be composable and expressive. ReQL includes features like map-reduce and joins, making it well-suited for complex queries.

4. Consistency Model: MongoDB follows a eventual consistency model, which means that changes made to the database may not be immediately reflected across all replicas. This allows for high availability and low latency, but may lead to eventual consistency issues. RethinkDB, on the other hand, follows a strong eventual consistency model, where updates are immediately visible to all replicas. This ensures stronger consistency but may introduce higher latency.

5. Administration and Monitoring: MongoDB provides a comprehensive set of tools for administration and monitoring, including MongoDB Management Service (MMS) and MongoDB Compass. These tools allow users to easily manage and monitor their MongoDB clusters. RethinkDB, on the other hand, does not have a dedicated administration and monitoring tool like MMS. Instead, users need to rely on third-party tools or build their own monitoring solutions.

6. Adoption and Community: MongoDB has a larger user base and a more mature ecosystem compared to RethinkDB. MongoDB is widely adopted by large organizations and has a thriving community of developers, making it easier to find resources and support. RethinkDB, while still popular in some niches, has a smaller user base and community.

In summary, MongoDB and RethinkDB differ in terms of their data replication and sharding mechanisms, real-time push architecture, query languages, consistency models, administration and monitoring tools, and adoption and community size.