MySQL Slow Query Log - SELECT /*!N SQL_NO_CACHE */
These types of SELECT are always performed by mysqldumps.

If you look in the slow log for the start time of the query and the time of each of these SELECTs is the same time every day, it is definitely coming from a mysqldump you have crontab'd somewhere.

To eliminate this, you may need to run this

SET GLOBAL slow_query_log = 'OFF';


Then go run the mysqldumps, and then run

SET GLOBAL slow_query_log = 'ON';


This should totally eliminate this type of SELECT from landing needlessly in the slow log.