查看表空间的名称及大小
复制代码 代码如下:
sql>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;
查看表空间物理文件的名称及大小:
复制代码 代码如下:
sql>select tablespace_name, file_id, file_name,round(bytes/(1024*1024),0) total_space from dba_data_files order by tablespace_name;
查看回滚段名称及大小:
复制代码 代码如下:
sql>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$rollstat v
where r.segment_id = v.usn(+) order by segment_name;
如何查看某个回滚段里面，跑的什么事物或者正在执行什么sql语句:
复制代码 代码如下:
sql>select d.sql_text,a.name
from v$rollname a,v$transaction b,v$session c,v$sqltext d
where a.usn=b.xidusn and b.addr=c.taddr and c.sql_address=
d.address and c.sql_hash_value=d.hash_value
and a.usn=1;
(备注：你要看哪个，就把usn=?写成几就行了)
查看控制文件:
sql>select * from v$controlfile;
查看日志文件:
sql> col member format a50
sql>select * from v$logfile;
如何查看当前sql*plus用户的sid和serial#:
sql>select sid, serial#, status from v$session where audsid=userenv(‘sessionid’);
如何查看当前数据库的字符集:
sql>select userenv(‘language’) from dual;
sql>select userenv(‘lang’) from dual;
怎么判断当前正在使用何种sql优化方式:
用explain plan产生explain plan，检查plan_table中id=0的position列的值。
sql>select decode(nvl(position,-1),-1,’rbo’,1,’cbo’) from plan_table where id=0;
如何查看系统当前最新的scn号：
sql>select max(ktuxescnw * power(2,32) + ktuxescnb) from x$ktuxe;
在oracle中查找trace文件的脚本:
sql>select u_dump.value || ‘/’ || instance.value || ‘_ora_’ ||
v$process.spid || nvl2(v$process.traceid, ‘_’ || v$process.traceid, null ) || ‘.trc'”trace file” from v$parameter u_dump cross join v$parameter instance cross join v$process join v$session on v$process.addr = v$session.paddr where u_dump.name = ‘user_dump_dest’ and
instance.name = ‘instance_name’ and v$session.audsid=sys_context(‘userenv’,’sessionid’);
sql>select d.value || ‘/ora_’ || p.spid || ‘.trc’ trace_file_name
from (select p.spid from sys.v_$mystat m,sys.v_$session s,
sys.v_$process p where m.statistic# = 1 and
s.sid = m.sid and p.addr = s.paddr) p,(select value from sys.v_$parameter where name =’user_dump_dest’) d;
如何查看客户端登陆的ip地址:
sql>select sys_context(‘userenv’,’ip_address’) from dual;
如何在生产数据库中创建一个追踪客户端ip地址的触发器：
复制代码 代码如下:
sql>create or replace trigger on_logon_trigger
after logon on database
begin
dbms_application_info.set_client_info(sys_context(‘userenv’, ‘ip_address’));
end;
rem 记录登陆信息的触发器
create or replace trigger logon_history
after logon on database –when (user=’wacos’) –only for user ‘wacos’
begin
insert into session_history
select username,sid,serial#,audsid,osuser,action,sysdate,null,sys_context(‘userenv’,’ip_address’),terminal,machine,program
from v$session where audsid = userenv(‘sessionid’);
end;
查询当前日期:
sql> select to_char(sysdate,’yyyy-mm-dd,hh24:mi:ss’) from dual;
查看所有表空间对应的数据文件名：
sql>select distinct file_name,tablespace_name,autoextensible from dba_data_files;
查看表空间的使用情况:
复制代码 代码如下:
sql>select sum(bytes)/(1024*1024) as free_space,tablespace_name
from dba_free_space group by tablespace_name;
sql>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;
column tablespace_name format a18;
column sum_m format a12;
column used_m format a12;
column free_m format a12;
column pto_m format 9.99;
select s.tablespace_name,ceil(sum(s.bytes/1024/1024))||’m’ sum_m,ceil(sum(s.usedspace/1024/1024))||’m’ used_m,ceil(sum(s.freespace/1024/1024))||’m’ free_m, sum(s.usedspace)/sum(s.bytes) ptused
from (select b.file_id,b.tablespace_name,b.bytes,
(b.bytes-sum(nvl(a.bytes,0))) usedspace,
sum(nvl(a.bytes,0)) freespace,(sum(nvl(a.bytes,0))/(b.bytes)) * 100 freepercentratio from sys.dba_free_space a,sys.dba_data_files b
where a.file_id(+)=b.file_id group by b.file_id,b.tablespace_name,b.bytes
order by b.tablespace_name) s group by s.tablespace_name
order by sum(s.freespace)/sum(s.bytes) desc;
查看数据文件的hwm（可以resize的最小空间）和文件头大小:
复制代码 代码如下:
select v1.file_name,v1.file_id,
num1 totle_space,
num3 free_space,
num1-num3 “used_space(hwm)”,
nvl(num2,0) data_space,
num1-num3-nvl(num2,0) file_head
from
(select file_name,file_id,sum(bytes) num1 from dba_data_files group by file_name,file_id) v1,
(select file_id,sum(bytes) num2 from dba_extents group by file_id) v2,
(select file_id,sum(bytes) num3 from dba_free_space group by file_id) v3
where v1.file_id=v2.file_id(+)
and v1.file_id=v3.file_id(+);
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