Find log history per hours
SELECT TO_CHAR(FIRST_TIME,’YYYY-MM-DD’) DAY, TO_CHAR(FIRST_TIME,’HH24′) HOUR, COUNT(*) TOTAL FROM V$LOG_HISTORY GROUP BY TO_CHAR(FIRST_TIME,’YYYY-MM-DD’),TO_CHAR(FIRST_TIME,’HH24′) ORDER BY TO_CHAR(FIRST_TIME,’YYYY-MM-DD’),TO_CHAR(FIRST_TIME,’HH24′) ASC /