Galera Cluster vs TiDB: What are the differences?

Introduction:

1. Key Difference - Scalability: Galera Cluster is a synchronous multi-master replication plugin for MariaDB and MySQL, providing high availability and synchronous replication. It scales well for write-heavy workloads but may face challenges with very large data sets. In contrast, TiDB is a distributed NewSQL database that horizontally scales out for both read and write operations. TiDB utilizes a distributed architecture with a transactional and analytical processing layer, providing better scalability for large data sets and high workload demands.

2. Key Difference - Consistency Model: In Galera Cluster, the default consistency model is strong consistency, ensuring that all nodes see the same set of transactions in the same order. This ensures data integrity but can lead to performance issues in high-latency networks. On the other hand, TiDB employs a consistency model known as linearizability, providing strong consistency guarantees while maintaining high availability and scalability. This allows TiDB to deliver consistent reads and writes across the distributed database without sacrificing performance.

3. Key Difference - Storage Engine: Galera Cluster supports multiple storage engines including InnoDB and MyISAM, allowing users to choose based on their specific requirements. In comparison, TiDB uses its own purpose-built storage engine known as TiKV, which is a distributed key-value store designed for high performance and scalability. TiKV leverages the Raft consensus algorithm to ensure fault tolerance and data consistency across the distributed database.

4. Key Difference - SQL Compatibility: Galera Cluster is fully compatible with MariaDB and MySQL, offering seamless migration options for users already familiar with these databases. TiDB, on the other hand, is compatible with the MySQL protocol, allowing existing MySQL applications to connect and interact with TiDB without any modifications. This enables users to leverage TiDB's distributed capabilities without the need for extensive code changes or rewrites.

5. Key Difference - Auto-Sharding: TiDB natively supports auto-sharding, dynamically partitioning data across multiple nodes to distribute the workload evenly and optimize performance. This automatic sharding simplifies database management and enhances scalability without the need for manual intervention. In contrast, Galera Cluster requires manual partitioning and configuration of nodes for load balancing, which can be complex and time-consuming, especially in large-scale deployments.

In Summary, Galera Cluster and TiDB differ in terms of scalability, consistency model, storage engine, SQL compatibility, and auto-sharding capabilities, making each suitable for different use cases based on specific requirements and workloads.