Parallel query execution is my favorite, non-existent, feature in MySQL. In all versions of MySQL – at least at the time of writing – when you run a single query it will run in one thread, effectively utilizing one CPU core only. Multiple queries run at the same time will be using different threads and will [&]

https://www.percona.com/blog/2019/01/17/using-parallel-query-with-amazon-aurora-for-mysql/