MySQL with an init script

docker-compose.mysql.template

  mysql:
    image: mysql:5.7
    ports:
      - 3306:3306
    volumes:
#      - ./volume/mysql:/var/lib/mysql:rw
      - ./scripts/mysql/demo.sql:/docker-entrypoint-initdb.d/demo.sql:ro
    environment:
      MYSQL_ALLOW_EMPTY_PASSWORD: "yes"
      MYSQL_DATABASE: "sample"
      MYSQL_USER: "sample"
      MYSQL_PASSWORD: "sample"
    restart: always

May I ask if there is a way to change the default wait_timeout? My system hits "hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection" every 8 hours or so. Somebody says its due to mysql connection idle timer kicking off. Before I found a solution on JDBC side, I need to set the idle timer longer now. Thanks in advance.

My issue could also be caused by the connection pool size. Could you also let me know how to set the pool size through the docker compose? Thanks, Harry