This section lists restrictions and limitations applying to event scheduling in MySQL 6.0.

Case sensitivity of event identifiers.  Event names are handled in case-insensitive fashion. For example, this means that you cannot have two events in the same database with the names anEvent and AnEvent.

Modification of events by stored routines and triggers.  An event may not be created, altered, or dropped by a trigger, stored routine, or another event. An event also may not create, alter, or drop triggers or stored routines. (Bug#16409, Bug#18896)

Resolution of event timings.  Event timings using the intervals YEAR, QUARTER, MONTH, and YEAR_MONTH are resolved in months; those using any other interval are resolved in seconds. There is no way to cause events scheduled to occur at the same second to execute in a given order. In addition — due to rounding, the nature of threaded applications, and the fact that a non-zero length of time is required to create events and to signal their execution — events may be delayed by as much as 1 or 2 seconds. However, the time shown in the INFORMATION_SCHEMA.EVENTS table's LAST_EXECUTED column or the mysql.event table's last_executed column is always accurate to within one second of the time the event was actually executed. (See also Bug#16522.)

Effects on statement counts.  Each execution of the statements contained in the body of an event takes place in a new connection; thus, these statements has no effect in a given user session on the server's statement counts such as Com_select and Com_insert that are displayed by SHOW STATUS. However, such counts are updated in the global scope. (Bug#16422)

Start times.  Events cannot be created with a start time that is in the past.

Latest time supported.  Events do not support times later than the end of the Unix Epoch; this is approximately the beginning of the year 2038. Such dates are specifically disallowed by the Event Scheduler. (Bug#16396)

Server SQL mode.  The SQL_MODE column in INFORMATION_SCHEMA.EVENTS shows the server SQL mode that was in effect when the event was created.

Dropping or altering events.  DROP USER drops all events for which that user was the definer; DROP SCHEMA drops all events associated with the dropped schema.

Database object references in ON SCHEDULE clauses.  References to stored functions, user-defined functions, and tables in the ON SCHEDULE clauses of CREATE EVENT and ALTER EVENT statements are not supported. These sorts of references are disallowed. (See Bug#22830 for more information.)

Disallowed statements.  Generally speaking, statements which are not permitted in stored routines or in SQL prepared statements are also not allowed in the body of an event. See Section D.1, “Restrictions on Stored Routines, Triggers, and Events”, and Section 12.7, “SQL Syntax for Prepared Statements”, for more information.