RediSQL vs Redis: What are the differences?

Introduction

RediSQL and Redis are both in-memory databases that are frequently used for caching and data storage purposes. While they share similarities, there are several key differences that set them apart.

1. Data Structure Support: One major difference between RediSQL and Redis is their support for data structures. Redis supports various data structures such as strings, hashes, lists, sets, and sorted sets. On the other hand, RediSQL primarily focuses on SQL functionality and lacks the wide range of data structures provided by Redis.

2. Querying Language: RediSQL supports SQL (Structured Query Language) as its querying language, allowing users to perform complex queries using familiar SQL syntax. In contrast, Redis does not have a built-in querying language and relies on its key-value store structure for data retrieval and manipulation.

3. Multi-Model Support: Redis is a multi-model database, meaning it allows users to work with different data models within a single database instance. It provides support for key-value, document, graph, and time-series data structures. RediSQL, however, specializes in SQL functionality and does not offer built-in support for other data models.

4. Durability and Persistence: Redis provides options for data persistence, allowing users to save data to disk and recover it after a system restart. RediSQL, being an in-memory database, does not inherently provide durability and persistence. However, it is possible to configure RediSQL to use Redis as a backend storage engine, leveraging Redis' persistence capabilities.

5. Transaction Support: Redis supports atomic transactions, which means that a group of commands can be executed as a single isolated operation. RediSQL, being an SQL-based database, also supports transactions using the standard SQL transaction syntax, enabling users to perform consistent and concurrent operations on their data.

6. Scalability: Both RediSQL and Redis are highly scalable systems. However, Redis has more extensive support for high availability and horizontal scalability through its Redis Cluster feature, allowing users to distribute their data across multiple instances seamlessly. RediSQL, while capable of running in a replicated setup, does not have built-in native support for horizontal scalability.

In summary, RediSQL differs from Redis by its focus on SQL functionality, limited support for data structures, usage of SQL querying language, lack of multi-model capabilities, and different durability and scalability features.