Oracle临时表空间主要用来做查询和存放一些缓冲区数据。临时表空间消耗的主要原因是需要对查询的中间结果进行排序
监控临时表空间:
COL TEMP_FILE FOR A60;
SELECT ROUND((F.BYTES_FREE + F.BYTES_USED)/1024/1024/1024, 2) AS "TOTAL(GB)",
ROUND(((F.BYTES_FREE + F.BYTES_USED) - NVL(P.BYTES_USED, 0))/1024/1024/1024,2) AS "FREE(GB)",
D.FILE_NAME AS "TEMP_FILE",
ROUND(NVL(P.BYTES_USED, 0)/1024/1024/1024, 2) AS "USED(GB)" ,
ROUND((F.BYTES_USED + F.BYTES_FREE)/1024/1024/1024, 2) AS "TOTAL(GB)",
ROUND(((F.BYTES_USED + F.BYTES_FREE) - NVL(P.BYTES_USED, 0))/1024/1024/1024, 2) AS "FREE(GB)" ,
ROUND(NVL(P.BYTES_USED, 0)/1024/1024/1024, 2) AS "USED(GB)"
FROM SYS.V_$TEMP_SPACE_HEADER F ,DBA_TEMP_FILES D ,SYS.V_$TEMP_EXTENT_POOL P
WHERE F.TABLESPACE_NAME(+) = D.TABLESPACE_NAME
AND F.FILE_ID(+) = D.FILE_ID
AND P.FILE_ID(+) = D.FILE_ID;
查看临时表空间对应的临时文件的使用情况:
SELECT TABLESPACE_NAME AS TABLESPACE_NAME ,
BYTES_USED/1024/1024/1024 AS TABLESAPCE_USED ,
BYTES_FREE/1024/1024/1024 AS TABLESAPCE_FREE
FROM V$TEMP_SPACE_HEADER
ORDER BY 1 DESC;
查找消耗临时表空间资源比较多的SQL语句
set line 300
col username for a10
col tablespace for a10
col sql_id for a13
col prev_sql_id for a13
select s.sid,
s.serial#,
s.username,
s.sql_id,
s.prev_sql_id,
u.tablespace,
u.contents,
u.segtype,
u.extents,
u.blocks,
round(((u.blocks * P.VALUE) / 1024 / 1024), 2) MB
from v$session s, v$sort_usage u, SYS.V_$SYSTEM_PARAMETER P
where s.saddr = u.session_addr
AND UPPER(P.NAME) = 'DB_BLOCK_SIZE'
order by MB DESC;
---执行以下命令释放temp表空间（详见文档：How to Release the Temp LOB Space and Avoid Hitting ORA-1652 (文档 ID 802897.1) ）
declare
clb clob;
ch varchar2(32767);
k number;
begin
dbms_lob.createtemporary(clb,true,dbms_lob.call);
for i in 1..1500 loop
ch:=lpad('o',32767,'Y');
dbms_lob.writeappend(clb,length(ch),ch);
end loop;
k:=dbms_lob.getlength(clb);
dbms_lob.freetemporary(clb);
dbms_output.put_line('the clob length: '||k);
end;
/
切换临时表空间
1：查看旧临时表空间信息
SELECT * FROM V$TEMPFILE
SELECT USERNAME, TEMPORARY_TABLESPACE FROM DBA_USERS
2：创建中转的临时表空间
3：添加相应的数据文件
4：切换临时表空间。
ALTER DATABASE DEFAULT TEMPORARY TABLESPACE TMP;
5：删除旧的临时表空间数据文件
DROP TABLESPACE TEMP INCLUDING CONTENTS AND DATAFILES;
6：如果有必要，重新指定用户临时表空间为新建的临时表空间
ALTER USER ODS TEMPORARY TABLESPACE TMP;
ALTER USER EDS TEMPORARY TABLESPACE TMP;
ALTER USER ETL TEMPORARY TABLESPACE TMP;
ALTER USER DM TEMPORARY TABLESPACE TMP;
收缩临时表空间
排序等操作使用的临时段，使用完成后会被标记为空闲，表示可以重用，占用的空间不会立即释放，有时候临时表空间会变得非常大，此时可以通过收缩临时表空间来释放没有使用的空间。收缩临时表空间是ORACLE 11g新增的功能。
SQL> ALTER TABLESPACE TEMP SHRINK SPACE KEEP 8G;
SQL> ALTER TABLESPACE TEMP SHRINK TEMPFILE '/u01/app/oracle/oradata/GSP/temp02.dbf'