How to Migrate from ClickHouse to MySQL

What is the fastest way to move ClickHouse data into MySQL?

Dump each ClickHouse table to CSV or Parquet, recreate the schema in MySQL, and bulk-load with LOAD DATA INFILE. This minimizes network chatter and leverages both engines’ bulk I/O performance.

How do I export a ClickHouse table safely?

Use clickhouse-client with SELECT ... FORMAT CSV piped to a file. Add --max_insert_threads to parallelize and --allow_experimental_parallel_reading_from_replicas=1 for larger datasets.

Example command

$ clickhouse-client --query="SELECT * FROM Orders FORMAT CSV" > orders.csv

How do I recreate the schema in MySQL?

Match ClickHouse types to MySQL equivalents: Int32 ➜ INT, Float64 ➜ DOUBLE, DateTime64 ➜ DATETIME(6). Create indexes after data load to speed up imports.

MySQL DDL for Orders

CREATE TABLE Orders( id INT PRIMARY KEY, customer_id INT, order_date DATETIME, total_amount DECIMAL(10,2) );

How do I bulk-load data into MySQL?

Enable LOCAL option if the file sits on the client. Disable foreign-key checks during load for speed.

Loading CSV into Orders

SET FOREIGN_KEY_CHECKS=0;\nLOAD DATA LOCAL INFILE 'orders.csv' INTO TABLE Orders\nFIELDS TERMINATED BY ',' ENCLOSED BY '"'\nLINES TERMINATED BY '\n'\n(id, customer_id, order_date, total_amount);\nSET FOREIGN_KEY_CHECKS=1;

How do I migrate multiple related tables?

Export and import tables in dependency order: Customers → Products → Orders → OrderItems. Validate row counts after each load.

What validation should I run after migration?

Count rows, verify sums (e.g., SUM(total_amount)), and sample records in both systems. Automate checks with a script.

Best practices for production migrations?

Run migrations off-peak, snapshot ClickHouse tables to avoid mutations during export, and keep retryable scripts in version control. Test in staging before production.