Description:
I find it problematic that an EVENT can 
"SET GLOBAL event_scheduler = off;"

the example below will NOT execute "every 5 minute" !

How to repeat:
DELIMITER $$

SET GLOBAL event_scheduler = ON $$  		

CREATE
EVENT `test`.`test`

ON SCHEDULE
        EVERY 5 MINUTE
	STARTS CURRENT_TIMESTAMP
	ENABLE

DO 
	BEGIN
	SET GLOBAL event_scheduler = off;
	END $$

DELIMITER ;

Suggested fix:
... hmmm .. I would consider disabling "SET GLOBAL event_scheduler" from inside an EVENT.

This is not a silly as it seems in my opinion, because if an EVENT executes a Stored procdure that executes ... then eventscheduler could inadvertedly be disabled!

Thank you for a problem report. It looks like execution of this SET statement should be prevented if called from event...

I think it 'not a real bug'.

http://dev.mysql.com/doc/refman/5.1/en/create-event.html
says
"In addition, if the event's definer has the SUPER privilege, that event may read and write global variables. As granting this privilege entails a potential for abuse, extreme care must be taken in doing so."

.. so it is documented like that.  But in the particular situation with "SET EVENT_SCHEDULER .." it is like removing the chair where you sit!

something related here:
http://bugs.mysql.com/bug.php?id=34787

And I do think that event_scheduler setting needs better protection than most server variables.

If you use EVENTs, it can be very critical if they get disabled!

Peter,

Thank you for the report.  We do agree that this is less than optimal behavior, but it works as documented currently.  Adding this restriction would be a useful feature to improve usability.

Regards,

Timothy

For me that's a bogus report. One can also empty mysql.event from an event that has SUPER and then complain why TRUNCATE or DELETE is available in the body of an event.

This is documented. Generally MySQL provides many ways to shoot oneself in the foot, and is quite liberal in that.