Azure SQL Database vs Clickhouse: What are the differences?

Introduction

In this Markdown code, we will discuss the key differences between Azure SQL Database and ClickHouse. Azure SQL Database is a fully managed relational database service provided by Microsoft Azure, while ClickHouse is an open-source columnar database management system developed by Yandex.

1. Scalability: Azure SQL Database offers horizontal scalability by allowing you to add or remove resources as per your needs. It utilizes a cloud-based architecture that automatically resizes the database to handle increased or decreased workloads. On the other hand, ClickHouse focuses on vertical scalability and is designed to efficiently handle huge volumes of data with a significantly higher read throughput.

2. Data Storage and Query Language: Azure SQL Database stores data in a row-based format and uses the SQL language for querying. It is suitable for structured data and supports various indexing options for faster query execution. In contrast, ClickHouse stores data in a columnar format, which is highly optimized for analytical workloads. ClickHouse uses its own query language, which is specifically designed for fast analytical queries.

3. Performance: Azure SQL Database offers high-performance OLTP (Online Transaction Processing) capabilities with low latency and high availability. It is suitable for transactional workloads and provides features like in-memory processing and automatic tuning. ClickHouse, on the other hand, excels in OLAP (Online Analytical Processing) workloads and is specifically designed for fast analytical queries on large datasets.

4. Data Partitioning: Azure SQL Database supports sharding, which allows you to split your data across multiple databases or servers for distributed processing. It provides flexible partitioning options based on ranges, lists, or hash functions. ClickHouse also supports partitioning but uses a different approach. It uses merge-tree tables that allow automatic partitioning based on the primary key and time column.

5. Data Replication and Availability: Azure SQL Database offers various replication options, including geo-replication for disaster recovery and high availability. It ensures automatic failover and provides built-in backup and restore capabilities. ClickHouse, on the other hand, provides replication through its distributed table feature, allowing you to replicate data across multiple ClickHouse instances for high availability and fault tolerance.

6. Cost Model: Azure SQL Database follows a pay-as-you-go pricing model, where you pay for the resources you consume. It offers various pricing tiers based on performance, storage, and features. ClickHouse, being open-source, is free to use and doesn't have any licensing costs. However, you need to consider the cost of hardware and infrastructure required to run ClickHouse clusters efficiently.

In summary, Azure SQL Database is a managed relational database service with horizontal scalability, row-based data storage, and optimized for OLTP workloads, while ClickHouse is an open-source columnar database system designed for vertical scalability, columnar data storage, and optimized for OLAP workloads.