[MariaDB discuss] Query Cache: Does a SELECT query tagged with SQL_NO_CACHE really touch the QC mutex?

Hello, I found the query cache in MariaDB to be super useful and especially powerful when used in DEMAND mode. So I'd like to learn more about the performance characteristics. The documentation says that for the query cache, "the mutex is hit even for SQL_NO_CACHE": https://mariadb.com/kb/en/mariadb-memory-allocation/#query-cache Is there some more information about this somewhere? Why would a SELECT query that uses this directive dabble with the mutex at all?