Clickhouse vs Exasol: What are the differences?

Introduction

Clickhouse and Exasol are both powerful databases designed for high-performance analytics and data processing. While they share some similarities, there are several key differences that set them apart. Below are six key differences between Clickhouse and Exasol:

1. Architecture: Clickhouse is a columnar database that stores and processes data in a column-oriented fashion. It excels at executing complex analytical queries and aggregations on large datasets. On the other hand, Exasol follows a hybrid architecture that combines row-based and columnar storage. This allows Exasol to efficiently handle both high-concurrency transactional workloads and complex analytical queries.

2. Scalability: Clickhouse is known for its exceptional scalability, with the ability to handle petabytes of data and effortlessly scale horizontally by adding more nodes to the cluster. Exasol, on the other hand, also offers horizontal scalability but with a more traditional shared-nothing architecture. It supports multi-node clusters but requires manual sharding for scalability, compared to Clickhouse's automatic partitioning capabilities.

3. Data Loading and Querying: Clickhouse excels in data ingestion and querying speed due to its unique data storage format and optimized query execution engine. It provides efficient bulk insert capabilities and parallel query processing, making it an excellent choice for real-time data analysis. Exasol, while also performing well in data loading and querying, may have slightly lower performance in comparison.

4. Data Replication and High Availability: Clickhouse provides built-in replication mechanisms, allowing data to be safely replicated across multiple nodes for high availability and fault tolerance. It supports both synchronous and asynchronous replication, providing flexibility and consistency options in data replication. Exasol, however, does not have built-in replication and relies on third-party tools or custom solutions for achieving high availability.

5. Data Types and Compatibility: Clickhouse offers a wide range of data types and is well-suited for handling various data formats commonly used in analytics. It also supports numerous SQL functions and language features, making it easier to migrate from traditional SQL databases. Exasol, while featuring a comprehensive set of data types, also offers strong compatibility with SQL standards and provides support for rich analytics functions and user-defined procedures.

6. Licensing and Cost: Clickhouse is an open-source project with a permissive license, making it highly cost-effective for organizations. It eliminates licensing costs and provides the freedom to modify and distribute the software. Exasol, on the other hand, is a commercial database and requires licensing for usage. While it offers a feature-rich environment, the associated costs may be a factor to consider for some organizations.

In summary, Clickhouse and Exasol offer different architectural approaches, scalability options, data loading and querying efficiencies, data replication capabilities, supported data types and compatibility, and licensing models. Understanding these key differences is crucial for selecting the database that best aligns with specific requirements and use cases.