Codec Usage in ClickHouse: Pros and Cons

ClickHouse is a powerful columnar DBMS designed for analytical tasks. One of the key and underestimated tools for optimizing data storage and processing in ClickHouse are codecs.

I will reveal how codecs LZ4, ZSTD, Delta, DoubleDelta help increase query speed and reduce storage volume, and highlight the challenges that arise when using them in projects.

We will consider the following topics:

• advantages of codecs: compact storage, adaptation to time series and high-frequency data;
• limitations: CPU load, dependence on data type, and risks of incorrect configuration;
• practical cases: real examples of codec implementation and their impact on performance;
• recommendations: how to choose the appropriate codec depending on the load scenario.

You will learn how to balance the benefits and limitations of codecs to achieve maximum performance in real-world tasks.

The topic will be useful for data engineers, data platform developers, and engineers who want to use ClickHouse more efficiently in their projects.