Memory - ClickHouse Documentation

The Memory database engine keeps its metadata and table definitions only in memory. It is intended for temporary databases: the database and its tables are lost when the server stops or restarts.

Creating a database

CREATE DATABASE temporary_data
ENGINE = Memory;

Usage

Create and use tables as in an Atomic database:

CREATE TABLE temporary_data.events
(
    id UInt64,
    name String
)
ENGINE = Memory;

INSERT INTO temporary_data.events VALUES (1, 'started');

Do not use this engine for data or definitions that must survive a restart. Use Atomic, the default open-source database engine, for persistent database metadata.

See also

Last modified on September 10, 2026