Tell about your experience working with databases — besides ClickHouse, what other databases and how deep?

Besides ClickHouse, I have experience with:

• PostgreSQL: Deep understanding of architecture, writing complex queries, setting up replication, optimizing indexes and performance, working with transactions and locks.

• MySQL: Experience in configuration and optimization, understanding the differences between InnoDB and MyISAM, working with replication and sharding.

• Redis: Using as a cache and message broker, setting up clusters, working with various data structures (strings, lists, sets).

• MongoDB: Experience with document-oriented model, building queries, indexing, replication, and sharding.

Overall, my experience covers both relational and non-relational databases, with a focus on performance, scalability, and reliability. In projects, I often combined several DBMS to solve different tasks.