臨時(shí)表空間作用http://blog.csdn.net/47522341/archive/2009/02/05/3864171.aspx

Oracle臨時(shí)表空間主要用來做查詢和存放一些緩沖區(qū)數(shù)據(jù)。臨時(shí)表空間消耗的主要原因是需要對查詢的中間結(jié)果進(jìn)行排序。

重啟數(shù)據(jù)庫可以釋放臨時(shí)表空間，如果不能重啟實(shí)例，而一直保持問題sql語句的執(zhí)行，temp表空間會(huì)一直增長。直到耗盡硬盤空間。

網(wǎng)上有人猜測在磁盤空間的分配上，oracle使用的是貪心算法，如果上次磁盤空間消耗達(dá)到1GB，那么臨時(shí)表空間就是1GB。也就是說當(dāng)前臨時(shí)表空間文件的大小是歷史上使用臨時(shí)表空間最大的大小。

臨時(shí)表空間的主要作用：

索引create或rebuild

Order by 或 group by

Distinct 操作

Union 或 intersect 或 minus

Sort-merge joins

analyze

查看臨時(shí)表空間大小

查看臨時(shí)表文件大小和已使用空間

select t1."Tablespace" "Tablespace",
t1."Total (G)" "Total (G)",
nvl(t2."Used (G)", 0) "Used(G)",
t1."Total (G)" - nvl(t2."Used (G)", 0) "Free (G)"
from
(
select tablespace_name "Tablespace", to_char(( sum (bytes/1024/1024/1024)),'99,999,990.900') "Total (G)"
from dba_temp_files
group by tablespace_name
union
select tablespace_name "Tablespace", to_char(( sum (bytes/1024/1024/1024)),'99,999,990.900') "Total (G)"
from dba_data_files
where tablespace_name like 'TEMP%'
group by tablespace_name
) t1,
(
select tablespace , round( sum (blocks)*8/1024) "Used (G)" from v$sort_usage
group by tablespace
) t2
where t1."Tablespace"=t2. tablespace (+)

查看當(dāng)前臨死表使用空間大小與正在占用臨時(shí)表空間的sql語句

select sess.SID, segtype, blocks*8/1000 "MB" ,sql_text
from v$sort_usage sort , v$session sess,v$sql sql
where sort .SESSION_ADDR = sess.SADDR
and sql .ADDRESS = sess.SQL_ADDRESS
order by blocks desc ;

select 'the ' || name || ' temp tablespaces ' || tablespace_name ||
?????? ' idle ' ||
?????? round(100 - (s.tot_used_blocks / s.total_blocks) * 100, 3) ||
?????? '% at ' || to_char( sysdate , 'yyyymmddhh24miss')
from ( select d.tablespace_name tablespace_name,
?????????????? nvl( sum (used_blocks), 0) tot_used_blocks,
?????????????? sum (blocks) total_blocks
????????? from v$sort_segment v, dba_temp_files d
???????? where d.tablespace_name = v.tablespace_name(+)
???????? group by d.tablespace_name) s,
?????? v$database;

修改臨時(shí)文件大小

select 'ALTER database TEMPFILE ' || file_name || ' resize 100M ;'
from dba_temp_files
where tablespace_name = 'ONLYDWTEMP';

ALTER database TEMPFILE '/oradata/ONLYDWTEMP06.dbf' resize 100M ;

ALTER database TEMPFILE '/oradata/ONLYDWTEMP07.dbf' resize 100M ;

ALTER database TEMPFILE '/oradata/ONLYDWTEMP08.dbf' resize 100M ;

ALTER database TEMPFILE '/oradata/ONLYDWTEMP09.dbf' resize 100M ;

ALTER database TEMPFILE '/oradata/ONLYDWTEMP10.dbf' resize 100M ;

ALTER database TEMPFILE '/oradata/ONLYDWTEMP01.dbf' resize 100M ;

ALTER database TEMPFILE '/oradata/ONLYDWTEMP02.dbf' resize 100M ;

ALTER database TEMPFILE '/oradata/ONLYDWTEMP03.dbf' resize 100M ;

ALTER database TEMPFILE '/oradata/ONLYDWTEMP04.dbf' resize 100M ;

ALTER database TEMPFILE '/oradata/ONLYDWTEMP05.dbf' resize 100M ;

SQL> ALTER database TEMPFILE '/oradata/ONLYDWTEMP09.dbf' resize 100M ;

ALTER database TEMPFILE '/oradata/ONLYDWTEMP09.dbf' resize 100M

ORA-03297: file contains used data beyond requested RESIZE value

創(chuàng)建新的臨時(shí)表空間

SQL> create temporary tablespace TEMP1 TEMPFILE '/oradata/TEMP1_01.dbf' size 100M;

Tablespace created

SQL> create temporary tablespace TEMP2 TEMPFILE '/oradata/TEMP2_01.dbf' size 100M;

Tablespace created

將當(dāng)前臨時(shí)表空間指定為新的臨時(shí)表空間

SQL> alter database default temporary tablespace TEMP1;

Database altered

刪除舊的臨時(shí)表空間

SQL> drop tablespace ONLYDWTEMP including contents and datafiles;

Tablespace dropped

http://blog.csdn.net/47522341/archive/2009/02/05/3864171.aspx

釋放臨時(shí)表空間實(shí)例