How does ClickHouse differ from Postgres/MySQL?

ClickHouse is a columnar analytical database management system optimized for processing large volumes of data and real-time analytical queries.

Main differences between ClickHouse and PostgreSQL/MySQL:

• Storage Model: ClickHouse uses columnar data storage, which significantly speeds up aggregations and analytical queries. PostgreSQL and MySQL are row-based DBMSs, better suited for transactional workloads.

• Purpose: ClickHouse is oriented towards OLAP (analytics), while PostgreSQL/MySQL are oriented towards OLTP (operational transactions).

• Scalability: ClickHouse is initially designed for horizontal scaling and handling petabytes of data.

• Consistency: PostgreSQL/MySQL provide strong consistency, while ClickHouse offers weaker consistency focused on speed and scale.

• Transaction Support: PostgreSQL/MySQL support full transactions, whereas ClickHouse does not or has limited support.

An example of using ClickHouse is web log analytics, where the speed of aggregation over large data volumes is crucial.