--查看被锁住的表
select b.owner,b.object_name,a.session_id,a.locked_mode
from v$locked_object a,dba_objects b
where b.object_id = a.object_id;
----查看被锁住的会话
select b.username,b.sid,b.serial#,logon_time
from v$locked_object a,v$session b
where a.session_id = b.sid order by b.logon_time;

--查看被阻塞的会话
select * from dba_waiters;

--查看引起死锁的会话
select sess.sid,
sess.serial#,
lo.oracle_username,
lo.os_user_name,
ao.object_name,
lo.locked_mode
from v$locked_object lo,
dba_objects ao,
v$session sess
where ao.object_id = lo.object_id and lo.session_id = sess.sid
order by ao.object_name ;
--释放锁或者杀掉ORACLE进程
alter system kill session sid,.serial#

--查看表空间大小和使用率
select a.tablespace_name, total, free, total-free as used, substr(free/total * 100, 1, 5) as "FREE%", substr((total - free)/total * 100, 1, 5) as "USED%" from
(select tablespace_name, sum(bytes)/1024/1024 as total from dba_data_files group by tablespace_name) a,
(select tablespace_name, sum(bytes)/1024/1024 as free from dba_free_space group by tablespace_name) b
where a.tablespace_name = b.tablespace_name
order by a.tablespace_name;

--某张表对应的数据库实例和表空间
select owner,table_name,tablespace_name from dba_tables where table_name='BILLS_BREAK';
--表空间下所表
select table_name from dba_tables where tablespace_name='USERS';

--表空间扩容
--1.先查询表空间在物理磁盘上存放的位置
SELECT tablespace_name, file_id, file_name, round(bytes / (1024 * 1024), 0) total_space
FROM dba_data_files where tablespace_name='USERS' ORDER BY tablespace_name ;
--2.改变数据文件的大小
alter database datafile '/oracle/app/oradata/mytablespace/my_01.dbf' resize 256M;
--3.验证
select bytes/1024/1024, tablespace_name from dba_data_files where tablespace_name='USERS';