Set the MySQL Isolation Level to READ COMMITTED

Kestra 2.0 requires MySQL connections to use the READ COMMITTED transaction isolation level.

What changed

Kestra’s JDBC queue needs READ COMMITTED to avoid deadlocks. PostgreSQL uses this level by default. MySQL defaults to REPEATABLE READ.

Kestra 2.0 checks the isolation level of its database connection. If the level is not READ COMMITTED, Kestra raises this error:

java.lang.IllegalStateException: Isolation level must be READ COMMITTED

Who is affected

You are affected if you run Kestra on MySQL and neither of these is set:

• transaction_isolation=READ-COMMITTED on the MySQL server
• transaction-isolation: TRANSACTION_READ_COMMITTED on the Kestra MySQL datasource

PostgreSQL, H2, and Kafka with Elasticsearch deployments are not affected.

How to migrate

Before you start Kestra 2.0, apply one of the following options.

Option 1: Set the level on the MySQL server

Add the setting to your MySQL option file (my.cnf), then restart MySQL:

[mysqld]
transaction_isolation=READ-COMMITTED

On a managed service such as Amazon RDS or Cloud SQL, set the transaction_isolation parameter in the parameter group or database flags.

This option changes the default for every client of the MySQL server.

Option 2: Set the level in the Kestra datasource

Add transaction-isolation to the MySQL datasource in your Kestra configuration:

datasources:
  mysql:
    url: jdbc:mysql://localhost:3306/kestra
    driver-class-name: com.mysql.cj.jdbc.Driver
    username: kestra
    password: k3str4
    dialect: MYSQL
    transaction-isolation: TRANSACTION_READ_COMMITTED

This option applies only to Kestra’s connections. Use it when you cannot change the server configuration or when other applications share the MySQL server.

Verify the setting

To check the server default, run this query in MySQL:

SELECT @@GLOBAL.transaction_isolation;

The query returns READ-COMMITTED when Option 1 is in place. If you used Option 2, the server value can stay REPEATABLE-READ.

After you start Kestra 2.0, confirm that the logs do not contain Isolation level must be READ COMMITTED.

For the full list of MySQL requirements, see MySQL settings.