ALTER TRACE EVENT SESSION session-name 
{ add-drop-trace-event [,...]  
  |  add-drop-target [, ...] ]
  | STATE = { START | STOP }
}

add-drop-trace-event :
{ ADD TRACE EVENT trace-event-name ... | DROP TRACE EVENT trace-event-name }

add-drop-target :
{ ADD TARGET target-name ... | DROP TARGET target-name }

target-name : filename

Adding or dropping trace events or targets from a running trace session causes the session to pause briefly to make the changes and then resume after the changes are made. You do not need to stop a tracing session to add or drop trace events or targets. Adding or removing a trace event from a session that has already started has the side effect that some trace events are missed while a session is temporarily paused.

You must have the MANAGE ANY TRACE SESSION system privilege.

None

• Event tracing
• CREATE TEMPORARY TRACE EVENT statement
• CREATE TEMPORARY TRACE EVENT SESSION statement
• DROP TRACE EVENT statement
• DROP TRACE EVENT SESSION statement
• NOTIFY TRACE EVENT statement
• sp_trace_events system procedure
• sp_trace_event_fields system procedure
• sp_trace_event_sessions system procedure
• sp_trace_event_session_events system procedure
• sp_trace_event_session_targets system procedure
• sp_trace_event_session_target_options system procedure
• Event Trace Data (ETD) File Management utility (dbmanageetd)
• System events

The following example creates a trace event called my_event, creates a trace event session called my_session, and starts the session:

CREATE TEMPORARY TRACE EVENT my_event( id INTEGER, information LONG VARCHAR );
CREATE TEMPORARY TRACE EVENT SESSION my_session
    ADD TRACE EVENT my_event, -- user event
    ADD TRACE EVENT SYS_ConsoleLog_Information -- system event
    ADD TARGET FILE ( SET filename_prefix='my_trace_file' ); -- add a target
ALTER TRACE EVENT SESSION my_session
     STATE = START;