–1、查看表空间的名称及大小
SELECT t.tablespace_name, round(SUM(bytes / (1024 * 1024)), 0) ts_size
FROM dba_tablespaces t, dba_data_files d
WHERE t.tablespace_name = d.tablespace_name
GROUP BY t.tablespace_name;
–2、查看表空间物理文件的名称及大小
SELECT tablespace_name,
file_id,
file_name,
round(bytes / (1024 * 1024), 0) total_space
FROM dba_data_files
ORDER BY tablespace_name;
–3、查看回滚段名称及大小
SELECT segment_name,
tablespace_name,
r.status,
(initial_extent / 1024) initialextent,
(next_extent / 1024) nextextent,
max_extents,
v.curext curextent
FROM dba_rollback_segs r, v$rollstat v
WHERE r.segment_id = v.usn(+)
ORDER BY segment_name;
–4、查看控制文件
SELECT NAME FROM v$controlfile;
–5、查看日志文件
SELECT MEMBER FROM v$logfile;
–6、查看表空间的使用情况
SELECT SUM(bytes) / (1024 * 1024) AS free_space, tablespace_name
FROM dba_free_space
GROUP BY tablespace_name;
SELECT a.tablespace_name,
a.bytes total,
b.bytes used,
c.bytes free,
(b.bytes * 100) / a.bytes "% USED",
(c.bytes * 100) / a.bytes "% FREE"
FROM sys.sm$ts_avail a, sys.sm$ts_used b, sys.sm$ts_free c
WHERE a.tablespace_name = b.tablespace_name
AND a.tablespace_name = c.tablespace_name;
–7、查看数据库库对象
SELECT owner, object_type, status, COUNT(*) count#
FROM all_objects
GROUP BY owner, object_type, status;
–8、查看数据库的版本　
SELECT version
FROM product_component_version
WHERE substr(product, 1, 6) = ‘Oracle’;
–9、查看数据库的创建日期和归档方式
SELECT created, log_mode, log_mode FROM v$database;
–10、查死锁：
SELECT l.session_id sid,
s.serial#,
l.locked_mode,
l.oracle_username,
l.os_user_name,
s.machine,
s.terminal,
o.object_name,
s.logon_time
FROM v$locked_object l, all_objects o, v$session s
WHERE l.object_id = o.object_id
AND l.session_id = s.sid
ORDER BY sid, s.serial#;

–用来杀死这个会话；
alter system kill session ‘sid,serial#’;

– 批量解锁
declare cursor mycur is
select b.sid,b.serial#
　　from v$locked_object a,v$session b
　　where a.session_id = b.sid group by b.sid,b.serial#;

begin
for cur in mycur
loop
execute immediate (’alter system kill session ‘‘‘||cur.sid || ‘,’|| cur.SERIAL# ||’’’ ’);
end loop;
end;