Be careful with this engine, it's easy to accidentally expose the password as you only need table read permissions if it wasn't set up using an external credential file.

https://github.com/ClickHouse/ClickHouse/issues/3311

I also had some pretty bad join performance (CH table joined to MySQL table), the quick solution to both of these is that we instead use the table function (https://clickhouse.com/docs/en/sql-reference/table-functions...) to copy the data periodically.