oracle apex debug mode

1f?p=app:page:session::YES/LEVELx:::
2-- x is between 1 (least detailed) and 9 (most detailed)
3f?p=100:1:&APP_SESSION.::YES
4f?p=100:1:&APP_SESSION.::LEVEL5
5-- OR
6APEX_DEBUG.enable(p_level)
7-- OR
8APEX_SESSION.set_debug(p_session_id,p_level)    -- p_level: NULL to disable

1DECLARE
2    l_value varchar2(100) := 'test value';
3    l_long_msg VARCHAR2(32767) := 'output anything up to varchar2 limit';
4BEGIN
5    APEX_DEBUG_MESSAGE.ENABLE_DEBUG_MESSAGES(p_level => 3);  -- 1 is most important
6    APEX_DEBUG_MESSAGE.LOG_MESSAGE(					-- Short message (4000 max)
7        p_message => 'l_value = ' || l_value, p_level => 1 ); 
8    APEX_DEBUG_MESSAGE.LOG_LONG_MESSAGE(
9        p_message => l_long_msg, p_level => 1 );   	-- Long message   
10    APEX_DEBUG.INFO('Information message');
11END;

1SELECT adb.APEX_USER,
2       adb.APPLICATION_ID, wal.APPLICATION_NAME, adb.PAGE_ID,
3       adb.MESSAGE, adb.MESSAGE_TIMESTAMP,
4       adb.PAGE_VIEW_ID, adb.SESSION_ID
5FROM APEX_WORKSPACE_ACTIVITY_LOG wal
6INNER JOIN APEX_DEBUG_MESSAGES adb
7ON wal.DEBUG_PAGE_VIEW_ID = adb.PAGE_VIEW_ID;