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

Oracle臨時表空間主要用來做查詢和存放一些緩沖區數據。臨時表空間消耗的主要原因是需要對查詢的中間結果進行排序。

重啟數據庫可以釋放臨時表空間，如果不能重啟實例，而一直保持問題sql語句的執行，temp表空間會一直增長。直到耗盡硬盤空間。

網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到1GB，那么臨時表空間就是1GB。也就是說當前臨時表空間文件的大小是歷史上使用臨時表空間最大的大小。

臨時表空間的主要作用：

索引create或rebuild

Order by 或 group by

Distinct 操作

Union 或 intersect 或 minus

Sort-merge joins

analyze

查看臨時表空間大小

查看臨時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 (+)

查看當前臨死表使用空間大小與正在占用臨時表空間的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

創建新的臨時表空間

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

將當前臨時表空間指定為新的臨時表空間

SQL> alter database default temporary tablespace TEMP1;

Database altered

刪除舊的臨時表空間

SQL> drop tablespace ONLYDWTEMP including contents and datafiles;

Tablespace dropped

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

釋放臨時表空間實例