Cassandra vs CockroachDB: What are the differences?

Introduction

Cassandra and CockroachDB are both popular distributed databases that are designed to handle large amounts of data and provide high availability. While they share some similarities, there are several key differences between the two.

1. Data Model: Cassandra is a NoSQL database that uses a key-value approach, where data is organized into tables with rows and columns. It supports a wide range of data types and allows for flexible schema changes. On the other hand, CockroachDB follows a relational data model, where data is stored in tables with strict schemas and relationships between tables are managed through foreign keys. This allows for more structured and consistent data management.

2. Consistency Model: Cassandra provides eventual consistency by default, where updates to data can take some time to propagate throughout the system. It supports tunable consistency levels, allowing users to choose between strong consistency and high availability. CockroachDB, on the other hand, provides strong consistency guarantees through its distributed consensus algorithm. It ensures that all replicas of data are consistent at all times, even in the presence of failures.

3. Transaction Support: Cassandra does not natively support multi-table transactions, and ACID transactions are only supported within a single partition. CockroachDB, on the other hand, provides full support for distributed ACID transactions across multiple tables and partitions. It uses a distributed transactional layer based on the Google Spanner architecture, ensuring data integrity and consistency.

4. Scaling and Sharding: Cassandra uses a decentralized architecture that allows for linear scalability by adding more nodes to the cluster. It uses consistent hashing to distribute data across nodes based on the partition key. CockroachDB also supports horizontal scalability through automatic sharding of data across nodes. It uses a range partitioning scheme to distribute data, ensuring that data is evenly distributed and can be accessed efficiently.

5. Fault Tolerance: Cassandra is designed to be highly fault-tolerant, with its decentralized architecture and ability to replicate data across multiple nodes. It uses a gossip protocol for failure detection and automatic replication. CockroachDB also provides high fault tolerance through automatic data replication and distributed consensus. It uses a distributed version of the Raft consensus algorithm to ensure data durability and availability.

6. Ease of Operations: Cassandra requires manual configuration and management of its cluster, including setting up replication factor, partitioning, and handling node failures. CockroachDB, on the other hand, provides automated operations and self-healing capabilities. It automatically handles tasks such as data rebalancing, node failures, and replication, making it easier to manage and operate.

Summary

In summary, Cassandra and CockroachDB differ in their data models, consistency models, transaction support, scaling and sharding mechanisms, fault tolerance approaches, and ease of operations. These differences make each database suitable for different use cases and provide distinct advantages in terms of data management, scalability, and fault tolerance.