ASA Database Administration Guide
  Automating Tasks Using Schedules and Events
    Schedule and event internals

How event handlers are executed

When an event handler is triggered, a temporary internal connection is made on which the event handler is executed. The handler is not executed on the connection that caused the handler to be triggered, and consequently statements such as MESSAGE .. TO CLIENT, which interact with the client application, are not meaningful within event handlers.

The temporary connection on which the handler is executed does not count towards the connection limit for licensing purposes.

Event creation requires DBA authority, and events execute with the permissions of their creator. If you wish event handlers to execute with non-DBA authority, you can call a procedure from within the handler, as stored procedures run with the permissions of their creator.

Any event errors are logged to the server console.