V$WAITCLASSMETRIC_HISTORY definition in Oracle Database 11.2
V$WAITCLASSMETRIC_HISTORY
SELECT
begin_time, -- BEGIN_TIME DATE
end_time, -- END_TIME DATE
intsize_csec, -- INTSIZE_CSEC NUMBER
wait_class#, -- WAIT_CLASS# NUMBER
wait_class_id, -- WAIT_CLASS_ID NUMBER
average_waiter_count, -- AVERAGE_WAITER_COUNT NUMBER
dbtime_in_wait, -- DBTIME_IN_WAIT NUMBER
time_waited, -- TIME_WAITED NUMBER
wait_count, -- WAIT_COUNT NUMBER
time_waited_fg, -- TIME_WAITED_FG NUMBER
wait_count_fg -- WAIT_COUNT_FG NUMBER
FROM
gv$waitclassmetric_history
WHERE
inst_id = USERENV('INSTANCE')