CockroachDB vs Vitess: What are the differences?

Introduction

Both CockroachDB and Vitess are popular database systems that offer distributed and scalable solutions for handling large datasets. While they share similarities, there are several key differences between the two.

1. Principle of Operation: CockroachDB is a distributed SQL database that is built on top of a distributed key-value store, allowing it to handle high availability and horizontal scalability. On the other hand, Vitess is a database clustering system specifically designed to run on top of MySQL. It provides sharding, replication, and query routing functionalities for scaling and managing MySQL databases.

2. Consistency Model: CockroachDB follows a strong consistency model, ensuring that all nodes see the same data at the same time. It achieves this by using a distributed consensus protocol called Raft. In contrast, Vitess follows a more relaxed consistency model known as "semi-sync replication." It allows for eventual consistency, where updates made to the database may take some time to propagate across all nodes.

3. Supported Databases: While CockroachDB is a standalone database system that supports SQL, Vitess is primarily designed to work with MySQL as a clustering layer. Vitess provides features like sharding and routing specifically for MySQL databases, whereas CockroachDB is agnostic to the underlying database engine.

4. Transactions and Locking: CockroachDB supports distributed ACID transactions, which allow operations to be grouped together and ensure a consistent state across multiple nodes. It uses a distributed transactional protocol called "Single-Row Serializable" to ensure serializability and isolation. Vitess, on the other hand, does not provide built-in support for distributed transactions. It relies on MySQL's transaction capabilities and locking mechanisms for handling transactional operations.

5. Query Routing: CockroachDB uses distributed SQL to route queries to the appropriate nodes for execution. It takes advantage of the distributed nature of the database to parallelize query execution across multiple nodes. Vitess, on the other hand, provides intelligent query routing and transparent sharding capabilities. It can automatically route queries to the appropriate shard based on the table being accessed, improving performance and scalability.

6. Data Model: CockroachDB provides a flexible data model that supports both structured and semi-structured data. It stores data in tables with rows and columns, similar to traditional relational databases. Vitess, on the other hand, follows the relational data model and stores data in tables with predefined schemas. It primarily focuses on scaling and managing large MySQL databases.

In summary, CockroachDB is a distributed SQL database that provides strong consistency, support for distributed transactions, and a flexible data model. Vitess, on the other hand, is a clustering system designed specifically for MySQL, offering sharding, replication, and query routing capabilities with a more relaxed consistency model.