常用SQL查询：

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、捕捉运行很久的SQL

column username format a12
column opname format a16
column progress format a8

select username,sid,opname,
      round(sofar*100 / totalwork,0) || '%' as progress,
      time_remaining,sql_text
from v$session_longops , v$sql
where time_remaining <> 0
and sql_address = address
and sql_hash_value = hash_value
/
11。查看数据表的参数信息
SELECT   partition_name, high_value, high_value_length, tablespace_name,
        pct_free, pct_used, ini_trans, max_trans, initial_extent,
        next_extent, min_extent, max_extent, pct_increase, FREELISTS,
        freelist_groups, LOGGING, BUFFER_POOL, num_rows, blocks,
        empty_blocks, avg_space, chain_cnt, avg_row_len, sample_size,
        last_analyzed
   FROM dba_tab_partitions
  --WHERE table_name = :tname AND table_owner = :towner
ORDER BY partition_position

12.查看还没提交的事务
select * from v$locked_object;
select * from v$transaction;

13。查找object为哪些进程所用
select
p.spid,
s.sid,
s.serial# serial_num,
s.username user_name,
a.type  object_type,
s.osuser os_user_name,
a.owner,
a.object object_name,
decode(sign(48 - command),
1,
to_char(command), 'Action Code #' || to_char(command) ) action,
p.program oracle_process,
s.terminal terminal,
s.program program,
s.status session_status  
from v$session s, v$access a, v$process p  
where s.paddr = p.addr and
     s.type = 'USER' and    
     a.sid = s.sid   and
  a.object='SUBSCRIBER_ATTR'
order by s.username, s.osuser

14。回滚段查看
select rownum, sys.dba_rollback_segs.segment_name Name, v$rollstat.extents
Extents, v$rollstat.rssize Size_in_Bytes, v$rollstat.xacts XActs,
v$rollstat.gets Gets, v$rollstat.waits Waits, v$rollstat.writes Writes,
sys.dba_rollback_segs.status status from v$rollstat, sys.dba_rollback_segs,
v$rollname where v$rollname.name(+) = sys.dba_rollback_segs.segment_name and
v$rollstat.usn (+) = v$rollname.usn order by rownum

15。耗资源的进程（top session）
select s.schemaname schema_name,    decode(sign(48 - command), 1,
to_char(command), 'Action Code #' || to_char(command) ) action,    status
session_status,   s.osuser os_user_name,   s.sid,         p.spid ,         s.serial# serial_num,  
nvl(s.username, '[Oracle process]') user_name,   s.terminal terminal,    
s.program program,   st.value criteria_value  from v$sesstat st,   v$session s  , v$process p  
where st.sid = s.sid and   st.statistic# = to_number('38') and   ('ALL' = 'ALL'
or s.status = 'ALL') and p.addr = s.paddr order by st.value desc,  p.spid asc, s.username asc, s.osuser asc

16。查看锁（lock）情况
select /*+ RULE */ ls.osuser os_user_name,   ls.username user_name,  
decode(ls.type, 'RW', 'Row wait enqueue lock', 'TM', 'DML enqueue lock', 'TX',
'Transaction enqueue lock', 'UL', 'User supplied lock') lock_type,  
o.object_name object,   decode(ls.lmode, 1, null, 2, 'Row Share', 3,
'Row Exclusive', 4, 'Share', 5, 'Share Row Exclusive', 6, 'Exclusive', null)
lock_mode,    o.owner,   ls.sid,   ls.serial# serial_num,   ls.id1,   ls.id2    
from sys.dba_objects o, (   select s.osuser,    s.username,    l.type,    
l.lmode,    s.sid,    s.serial#,    l.id1,    l.id2   from v$session s,    
v$lock l   where s.sid = l.sid ) ls  where o.object_id = ls.id1 and    o.owner
<> 'SYS'   order by o.owner, o.object_name

17。查看等待（wait）情况
SELECT v$waitstat.class, v$waitstat.count count, SUM(v$sysstat.value) sum_value
FROM v$waitstat, v$sysstat WHERE v$sysstat.name IN ('db block gets',
'consistent gets') group by v$waitstat.class, v$waitstat.count

18。查看sga情况
SELECT NAME, BYTES FROM SYS.V_$SGASTAT ORDER BY NAME ASC

19。查看catched object
SELECT owner,              name,              db_link,              namespace,  
           type,              sharable_mem,              loads,              executions,  
          locks,              pins,              kept        FROM v$db_object_cache
         
20。查看V$SQLAREA
SELECT SQL_TEXT, SHARABLE_MEM, PERSISTENT_MEM, RUNTIME_MEM, SORTS,
VERSION_COUNT, LOADED_VERSIONS, OPEN_VERSIONS, USERS_OPENING, EXECUTIONS,
USERS_EXECUTING, LOADS, FIRST_LOAD_TIME, INVALIDATIONS, PARSE_CALLS, DISK_READS,
BUFFER_GETS, ROWS_PROCESSED FROM V$SQLAREA

21。查看object分类数量
select decode (o.type#,1,'INDEX' , 2,'TABLE' , 3 , 'CLUSTER' , 4, 'VIEW' , 5 ,
'SYNONYM' , 6 , 'SEQUENCE' , 'OTHER' ) object_type , count(*) quantity from
sys.obj$ o where o.type# > 1 group by decode (o.type#,1,'INDEX' , 2,'TABLE' , 3
, 'CLUSTER' , 4, 'VIEW' , 5 , 'SYNONYM' , 6 , 'SEQUENCE' , 'OTHER' ) union select
'COLUMN' , count(*) from sys.col$ union select 'DB LINK' , count(*) from

22。按用户查看object种类
select u.name schema,   sum(decode(o.type#, 1, 1, NULL)) indexes,  
sum(decode(o.type#, 2, 1, NULL)) tables,   sum(decode(o.type#, 3, 1, NULL))
clusters,   sum(decode(o.type#, 4, 1, NULL)) views,   sum(decode(o.type#, 5, 1,
NULL)) synonyms,   sum(decode(o.type#, 6, 1, NULL)) sequences,  
sum(decode(o.type#, 1, NULL, 2, NULL, 3, NULL, 4, NULL, 5, NULL, 6, NULL, 1))
others   from sys.obj$ o, sys.user$ u   where o.type# >= 1 and    u.user# =
o.owner# and   u.name <> 'PUBLIC'   group by u.name    order by
sys.link$ union select 'CONSTRAINT' , count(*) from sys.con$

23。有关connection的相关信息
1）查看有哪些用户连接
select s.osuser os_user_name,    decode(sign(48 - command), 1, to_char(command),
'Action Code #' || to_char(command) ) action,     p.program oracle_process,    
status session_status,    s.terminal terminal,    s.program program,    
s.username user_name,    s.fixed_table_sequence activity_meter,    '' query,    
0 memory,    0 max_memory,     0 cpu_usage,    s.sid,   s.serial# serial_num    
from v$session s,    v$process p   where s.paddr=p.addr and    s.type = 'USER'  
order by s.username, s.osuser
2）根据v.sid查看对应连接的资源占用等情况
select n.name,
 v.value,
 n.class,
 n.statistic#  
from  v$statname n,
 v$sesstat v
where v.sid = 71 and
 v.statistic# = n.statistic#
order by n.class, n.statistic#
3）根据sid查看对应连接正在运行的sql
select /*+ PUSH_SUBQ */
 command_type,
 sql_text,
 sharable_mem,
 persistent_mem,
 runtime_mem,
 sorts,
 version_count,
 loaded_versions,
 open_versions,
 users_opening,
 executions,
 users_executing,
 loads,
 first_load_time,
 invalidations,
 parse_calls,
 disk_reads,
 buffer_gets,
 rows_processed,
 sysdate start_time,
 sysdate finish_time,
 '>' || address sql_address,
 'N' status
from v$sqlarea
where address = (select sql_address from v$session where sid = 71)

24．查询表空间使用情况
select a.tablespace_name "表空间名称",
100-round((nvl(b.bytes_free,0)/a.bytes_alloc)*100,2) "占用率(%)",
round(a.bytes_alloc/1024/1024,2) "容量(M)",
round(nvl(b.bytes_free,0)/1024/1024,2) "空闲(M)",
round((a.bytes_alloc-nvl(b.bytes_free,0))/1024/1024,2) "使用(M)",
Largest "最大扩展段(M)",
to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') "采样时间"
from  (select f.tablespace_name,
   sum(f.bytes) bytes_alloc,
   sum(decode(f.autoextensible,'YES',f.maxbytes,'NO',f.bytes)) maxbytes
from dba_data_files f
group by tablespace_name) a,
(select  f.tablespace_name,
    sum(f.bytes) bytes_free
from dba_free_space f
group by tablespace_name) b,
(select round(max(ff.length)*16/1024,2) Largest,
   ts.name tablespace_name
from sys.fet$ ff, sys.file$ tf,sys.ts$ ts
where ts.ts#=ff.ts# and ff.file#=tf.relfile# and ts.ts#=tf.ts#
group by ts.name, tf.blocks) c
where a.tablespace_name = b.tablespace_name and a.tablespace_name = c.tablespace_name

25. 查询表空间的碎片程度

select tablespace_name,count(tablespace_name) from dba_free_space group by tablespace_name
having count(tablespace_name)>10;

alter tablespace name coalesce;
alter table name deallocate unused;

create or replace view ts_blocks_v as
select tablespace_name,block_id,bytes,blocks,'free space' segment_name from dba_free_space
union all
select tablespace_name,block_id,bytes,blocks,segment_name from dba_extents;

select * from ts_blocks_v;

select tablespace_name,sum(bytes),max(bytes),count(block_id) from dba_free_space
group by tablespace_name;

26。查询有哪些数据库实例在运行
select inst_name from v$active_instances;



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2003-11-22

更新历史：
2003-11-22   完成。
2004-1-15  修改26条的错误。
active_instances 应为 v$active_instances
多谢chinaunix的jiguang发现并反映该错误。