Citus vs YugabyteDB: What are the differences?

Introduction: Citus and YugabyteDB are both popular distributed SQL databases that offer horizontal scalability and high availability. However, they have distinct differences that may influence the choice of database for specific use cases.

1. Architecture: Citus is an extension to PostgreSQL that transforms it into a distributed database, whereas YugabyteDB is built from the ground up as a distributed SQL database with a distributed architecture that incorporates the PostgreSQL API.

2. Sharding Strategy: Citus uses a technique known as transparent data sharding to distribute data across a cluster of machines based on a sharding key, enabling parallel processing and query execution. In contrast, YugabyteDB employs a range-based sharding strategy that automatically distributes data across tablets based on the data's primary key values.

3. Consistency Model: Citus supports both strong and eventual consistency levels for reads and writes, allowing users to choose between consistency and performance. On the other hand, YugabyteDB offers strong consistency by default, ensuring that all reads across the distributed cluster are consistent with the most recent write.

4. Deployment Flexibility: Citus can be deployed either as a fully-managed service on Citus Cloud or as self-hosted software on various cloud platforms. In contrast, YugabyteDB provides a managed service on Yugabyte Cloud and supports self-managed deployments on Kubernetes, virtual machines, or bare metal servers.

5. Data Distribution: Citus partitions data within a distributed database by shard, and each shard resides on a specific node within the cluster, ensuring data locality and efficient query execution. YugabyteDB, on the other hand, replicates data across nodes to provide fault tolerance and ensure high availability.

6. Global Data Distribution: YugabyteDB offers built-in capabilities for multi-region and multi-cloud data distribution, enabling users to replicate and distribute data across geographically dispersed locations for geographic redundancy and low-latency access. Citus requires additional configuration and setup to achieve similar multi-region deployment patterns.

In Summary, Citus and YugabyteDB offer unique architectural approaches and features such as sharding strategies, consistency models, deployment flexibility, and data distribution mechanisms that cater to distinct use cases and requirements in distributed SQL database environments.