Database Engines

Database engines allow you to work with tables. By default, ClickHouse uses the Atomic database engine, which provides configurable table engines and an SQL dialect.

Here is a complete list of available database engines. Follow the links for more details:

Page	Description
Atomic	The Atomic engine supports non-blocking DROP TABLE and RENAME TABLE queries, and atomic EXCHANGE TABLESqueries. The Atomic database engine is used by default.
Backup	Allows to instantly attach table/database from backups in read-only mode.
Lazy	Keeps tables in RAM only expiration_time_in_seconds seconds after last access. Can be used only with Log type tables.
MaterializedPostgreSQL	Creates a ClickHouse database with tables from PostgreSQL database.
MySQL	Allows connecting to databases on a remote MySQL server and perform INSERT and SELECT queries to exchange data between ClickHouse and MySQL.
PostgreSQL	Allows to connect to databases on a remote PostgreSQL server.
Replicated	The engine is based on the Atomic engine. It supports replication of metadata via DDL log being written to ZooKeeper and executed on all of the replicas for a given database.
SQLite	Allows to connect to SQLite databases and perform INSERT and SELECT queries to exchange data between ClickHouse and SQLite.