UNDO required size - using Stats

 SELECT 'The Required undo tablespace size using Statistics In Memory is ' || dbms_undo_adv.required_undo_size(900) || ' MB' required_undo_size FROM dual;

Query to get 10 Large Object in Oracle Database

SELECT * FROM (select SEGMENT_NAME,SEGMENT_TYPE,BYTES/1024/1024/1024 GB,TABLESPACE_NAME from dba_segments order by 3 desc) WHERE ROWNUM <= 10;

Recovery file usage

 col name     format a32
col size_mb  format 999,999,999
col used_mb  format 999,999,999
col pct_used format 999
select
   name,
   ceil( space_limit / 1024 / 1024) size_mb,
   ceil( space_used / 1024 / 1024) used_mb,
   decode( nvl( space_used, 0),0, 0,
   ceil ( ( space_used / space_limit) * 100) ) pct_used
from
    v$recovery_file_dest
order by
   name desc;

Meta data tablespace

 

set lines 190
set pages 5000
set long 50000
set head off echo off
select 'select dbms_metadata.get_ddl(''TABLESPACE'','''
|| tablespace_name || ''') from dual;' from dba_tablespaces where tablespace_name='TSTDOCMGMT01'; 

killing inactive session from Oracle database

 SELECT    'ALTER SYSTEM KILL SESSION '''
      || s.sid
      || ','
      || s.serial#
      || ''' IMMEDIATE;'
         AS ddl
FROM v$session s
WHERE s.status='INACTIVE';