Query to identify which schema's are taking up space

set pages 999
col "size MB" format 999,999,999
col "Objects" format 999,999,999
select obj.owner "Owner"
, obj_cnt "Objects"
, decode(seg_size, NULL, 0, seg_size) "size MB"
from (select owner, count(*) obj_cnt from dba_objects group by owner) obj
, (select owner, ceil(sum(bytes)/1024/1024) seg_size
from dba_segments group by owner) seg
where obj.owner = seg.owner(+)
order by 3 desc ,2 desc, 1
/

Find the number of archivelogs generated each hour of the day

col MidN format 999
col 1AM format 999
col 2AM format 999
col 3AM format 999
col 4AM format 999
col 5AM format 999
col 6AM format 999
col 7AM format 999
col 8AM format 999
col 9AM format 999
col 10AM format 999
col 11AM format 999
col Noon format 999
col 1PM format 999
col 2PM format 999
col 3PM format 999
col 4PM format 999
col 5PM format 999
col 6PM format 999
col 7PM format 999
col 8PM format 999
col 9PM format 999
col 10PM format 999
col 11PM format 999
select to_char(first_time,'mm/dd/yy') logdate,
sum(decode(to_char(first_time,'hh24'),'00',1,0)) "MidN",
sum(decode(to_char(first_time,'hh24'),'01',1,0)) "1AM",
sum(decode(to_char(first_time,'hh24'),'02',1,0)) "2AM",
sum(decode(to_char(first_time,'hh24'),'03',1,0)) "3AM",
sum(decode(to_char(first_time,'hh24'),'04',1,0)) "4AM",
sum(decode(to_char(first_time,'hh24'),'05',1,0)) "5AM",
sum(decode(to_char(first_time,'hh24'),'06',1,0)) "6AM",
sum(decode(to_char(first_time,'hh24'),'07',1,0)) "7AM",
sum(decode(to_char(first_time,'hh24'),'08',1,0)) "8AM",
sum(decode(to_char(first_time,'hh24'),'09',1,0)) "9AM",
sum(decode(to_char(first_time,'hh24'),'10',1,0)) "10AM",
sum(decode(to_char(first_time,'hh24'),'11',1,0)) "11AM",
sum(decode(to_char(first_time,'hh24'),'12',1,0)) "Noon",
sum(decode(to_char(first_time,'hh24'),'13',1,0)) "1PM",
sum(decode(to_char(first_time,'hh24'),'14',1,0)) "2PM",
sum(decode(to_char(first_time,'hh24'),'15',1,0)) "3PM",
sum(decode(to_char(first_time,'hh24'),'16',1,0)) "4PM",
sum(decode(to_char(first_time,'hh24'),'17',1,0)) "5PM",
sum(decode(to_char(first_time,'hh24'),'18',1,0)) "6PM",
sum(decode(to_char(first_time,'hh24'),'19',1,0)) "7PM",
sum(decode(to_char(first_time,'hh24'),'20',1,0)) "8PM",
sum(decode(to_char(first_time,'hh24'),'21',1,0)) "9PM",
sum(decode(to_char(first_time,'hh24'),'22',1,0)) "10PM",
sum(decode(to_char(first_time,'hh24'),'23',1,0)) "11PM"
from v$log_history
group by to_char(first_time,'mm/dd/yy')
order by 1
/

Query to find number of archive logs getting generated every day

SELECT A.*,
Round(A.Count#*B.AVG#/1024/1024) Daily_Avg_Mb
FROM
(
SELECT
To_Char(First_Time,’YYYY-MM-DD’) DAY,
Count(1) Count#,
Min(RECID) Min#,
Max(RECID) Max#
FROM
v$log_history
GROUP
BY To_Char(First_Time,’YYYY-MM-DD’)
ORDER
BY 1 DESC
) A,
(
SELECT
Avg(BYTES) AVG#,
Count(1) Count#,
Max(BYTES) Max_Bytes,
Min(BYTES) Min_Bytes
FROM
v$log
) B;