Get size of the database 

col "Database Size" format a20

col "Free space" format a20

col "Used space" format a20

select round(sum(used.bytes) / 1024 / 1024 / 1024 ) || ' GB' "Database Size"

, round(sum(used.bytes) / 1024 / 1024 / 1024 ) -

round(free.p / 1024 / 1024 / 1024) || ' GB' "Used space"

, round(free.p / 1024 / 1024 / 1024) || ' GB' "Free space"

from (select bytes

from v$datafile

union all

select bytes

from v$tempfile

union all

select bytes

from v$log) used

, (select sum(bytes) as p

from dba_free_space) free

group by free.p

/ 

View hidden parameter setting 

Set lines 2000
col NAME for a45
col DESCRIPTION for a100
SELECT name,description from SYS.V$PARAMETER WHERE name LIKE '\_%' ESCAPE '\'

/

Archive generation per hour 

set lines 299

SELECT TO_CHAR(TRUNC(FIRST_TIME),'Mon DD') "DG Date",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'00',1,0)),'9999') "12AM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'01',1,0)),'9999') "01AM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'02',1,0)),'9999') "02AM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'03',1,0)),'9999') "03AM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'04',1,0)),'9999') "04AM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'05',1,0)),'9999') "05AM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'06',1,0)),'9999') "06AM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'07',1,0)),'9999') "07AM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'08',1,0)),'9999') "08AM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'09',1,0)),'9999') "09AM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'10',1,0)),'9999') "10AM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'11',1,0)),'9999') "11AM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'12',1,0)),'9999') "12PM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'13',1,0)),'9999') "1PM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'14',1,0)),'9999') "2PM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'15',1,0)),'9999') "3PM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'16',1,0)),'9999') "4PM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'17',1,0)),'9999') "5PM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'18',1,0)),'9999') "6PM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'19',1,0)),'9999') "7PM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'20',1,0)),'9999') "8PM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'21',1,0)),'9999') "9PM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'22',1,0)),'9999') "10PM",

TO_CHAR(SUM(DECODE(TO_CHAR(FIRST_TIME,'HH24'),'23',1,0)),'9999') "11PM"

FROM V$LOG_HISTORY

GROUP BY TRUNC(FIRST_TIME)

ORDER BY TRUNC(FIRST_TIME) DESC

/ 

Database growth per month 

select to_char(creation_time, 'MM-RRRR') "Month", sum(bytes)/1024/1024/1024 "Growth in GB

from sys.v_$datafile

where to_char(creation_time,'RRRR')='&YEAR_IN_YYYY_FORMAT'

group by to_char(creation_time, 'MM-RRRR')

order by to_char(creation_time, 'MM-RRRR'); 

View/modify AWR retention 

-- View current AWR retention period

select retention from dba_hist_wr_control;

-- Modify retention period to 7 days and interval to 30 min

select dbms_workload_repository.modify_snapshot_settings (interval => 30, retention => 10080);

NOTE - 7 DAYS = 7*24*3600= 10080 minutes

Purge old awr snapshots 

-- Find the AWR snapshot details.

select snap_id,begin_interval_time,end_interval_time from sys.wrm$_snapshot order by snap_id

-- Purge snapshot between snapid 612 to 700

execute dbms_workload_repository.drop_snapshot_range(low_snap_id =>612 , high_snap_id =>700);

-- Verify again

select snap_id,begin_interval_time,end_interval_time from sys.wrm$_snapshot order by snap_id