select bytes/1024/1024,TABLESPACE_NAME from dba_free_space where tablespace_name='MES_USER' ORDER BY BYTES DESC
***********************************************************************************************

*************  查询chained row ****************************
select table_name , chain_cnt from user_tables order by chain_cnt desc ;
***********************************************************************************************

*************查询当前运行的sql****************************
select a.username,a.machine,a.program,b.spid,c.sql_text from v$session a,v$process b,v$sqlarea c
where a.paddr=b.addr and  c.hash_value=a.sql_hash_value and c.address=a.sql_address and b.spid=
***********************************************************************************************

*************查询当前运行的程序****************************
select a.username,a.machine,a.program,b.spid,a.serial#,a.sid from v$session a,v$process b
where a.paddr=b.addr and b.spid in ()

select a.username,a.machine,a.program,b.spid,a.serial#,a.sid from v$session a,v$process b
where a.paddr=b.addr and a.sid in ()

SELECT a.machine,a.terminal,a.osuser, a.username, b.sql_text
from v$session a, v$sqlarea b, v$process  c
where a.sql_address =b.address  and  a.paddr=c.addr
      and c.spid in ()
order by b.address

**********************************************************************************************
kill session
**********************************************************************************************

SELECT sid, serial#, username
FROM v$session

  SID   SERIAL# USERNAME
----- --------- ----------------
    1         1
    2         1
    3         1
    4         1
    5         1
    7         1
    8        28 OPS$BQUIGLEY
   10       211 OPS$SWIFT
   11        39 OPS$OBRIEN
   12        13 SYSTEM 
   13         8 SCOTT

The following statement kills the session of the user scott using the SID and SERIAL# values from V$SESSION:

ALTER SYSTEM KILL SESSION '13, 8';

----------------------------------------------------------------------------------------------------

Linux 下kill Pid
kill -9 pid 

windows orakill

C:>orakill

Usage:  orakill sid thread

  where sid    = the Oracle instance to target
        thread = the thread id of the thread to kill

  The thread id should be retrieved from the spid column of a query such as:

        select spid, osuser, s.program from
        v$process p, v$session s where p.addr=s.paddr

***********************************************************************************************

*************查看数据库中对象空间是否成几何增长***************

select * from dba_segments where pct_increase='50' and owner not in ('SYS','SYSTEM')

***********************************************************************************************

*************查看当前用户使用的操作****************************

SELECT a.machine,a.terminal,a.osuser, a.username, b.sql_text
from v$session a, v$sqlarea b
where a.sql_address =b.address order by b.address

***********************************************************************************************

*************监控事例的等待**************************** 

select event,sum(decode(wait_Time,0,0,1)) "Prev",
sum(decode(wait_Time,0,1,0)) "Curr",count(*) "Tot"
from v$session_Wait
group by event order by 4;

***********************************************************************************************

2. 回滚段的使用情况

select name, waits, gets, waits/gets "Ratio"
from v$rollstat a, v$rollname b
where a.usn = b.usn;
***********************************************************************************************

3. 监控表空间的 I/O 比例

select df.tablespace_name name,df.file_name "file",f.phyrds pyr,
f.phyblkrd pbr,f.phywrts pyw, f.phyblkwrt pbw
from v$filestat f, dba_data_files df
where f.file# = df.file_id
order by df.tablespace_name;
***********************************************************************************************

4. 监控文件系统的 I/O 比例

select substr(a.file#,1,2) "#", substr(a.name,1,30) "Name",
a.status, a.bytes, b.phyrds, b.phywrts
from v$datafile a, v$filestat b
where a.file# = b.file#;
***********************************************************************************************

5.在某个用户下找所有的索引

select user_indexes.table_name, user_indexes.index_name,uniqueness, column_name
from user_ind_columns, user_indexes
where user_ind_columns.index_name = user_indexes.index_name
and user_ind_columns.table_name = user_indexes.table_name
order by user_indexes.table_type, user_indexes.table_name,
user_indexes.index_name, column_position;

***********************************************************************************************

6. 监控 SGA 的命中率 (data buffer)

select a.value + b.value "logical_reads", c.value "phys_reads",
round(100 * ((a.value+b.value)-c.value) / (a.value+b.value)) "BUFFER HIT RATIO"
from v$sysstat a, v$sysstat b, v$sysstat c
where a.statistic# = 38 and b.statistic# = 39
and c.statistic# = 40;
***********************************************************************************************

7. 监控 SGA 中字典缓冲区的命中率

select parameter, gets,Getmisses , getmisses/(gets+getmisses)*100 "miss ratio",
(1-(sum(getmisses)/ (sum(gets)+sum(getmisses))))*100 "Hit ratio"
from v$rowcache
where gets+getmisses <>0
group by parameter, gets, getmisses;
***********************************************************************************************

8. 监控 SGA 中共享缓存区的命中率，应该小于1%

select sum(pins) "Total Pins", sum(reloads) "Total Reloads",
sum(reloads)/sum(pins) *100 libcache
from v$librarycache;

select sum(pinhits-reloads)/sum(pins) "hit radio",sum(reloads)/sum(pins) "reload percent"
from v$librarycache;
***********************************************************************************************

9. 显示所有数据库对象的类别和大小

select count(name) num_instances ,type ,sum(source_size) source_size ,
sum(parsed_size) parsed_size ,sum(code_size) code_size ,sum(error_size) error_size,
sum(source_size) +sum(parsed_size) +sum(code_size) +sum(error_size) size_required
from dba_object_size
group by type order by 2;
***********************************************************************************************

10. 监控 SGA 中重做日志缓存区的命中率，应该小于1%

SELECT name, gets, misses, immediate_gets, immediate_misses,
Decode(gets,0,0,misses/gets*100) ratio1,
Decode(immediate_gets+immediate_misses,0,0,
immediate_misses/(immediate_gets+immediate_misses)*100) ratio2
FROM v$latch WHERE name IN ('redo allocation', 'redo copy'); 

##  Shared pool hit radio
select sum(pinhits)/sum(pins)*100 "shared pool hit radio",sum(reloads)/sum(pins) "reload percent"  from v$librarycache ; 

***********************************************************************************************

11. 监控内存和硬盘的排序比率，最好使它小于 .10，增加 sort_area_size

SELECT name, value FROM v$sysstat WHERE name IN ('sorts (memory)', 'sorts (disk)');
The smallest , the best  :     sorts (disk)/(sorts (memory)+sorts (disk)) 
***********************************************************************************************

12. 监控当前数据库谁在运行什幺SQL语句

SELECT osuser, username, sql_text from v$session a, v$sqltext b
where a.sql_address =b.address order by address, piece;

***********************************************************************************************
13. 监控字典缓冲区

SELECT (SUM(PINS - RELOADS)) / SUM(PINS) "LIB CACHE" FROM V$LIBRARYCACHE;
SELECT (SUM(GETS - GETMISSES - USAGE - FIXED)) / SUM(GETS) "ROW CACHE" FROM V$ROWCACHE;
SELECT SUM(PINS) "EXECUTIONS", SUM(RELOADS) "CACHE MISSES WHILE EXECUTING" FROM V$LIBRARYCACHE;

后者除以前者,此比率小于1%,接近0%为好。

SELECT SUM(GETS) "DICTIONARY GETS",SUM(GETMISSES) "DICTIONARY CACHE GET MISSES"
FROM V$ROWCACHE

***********************************************************************************************