????? Oracle 臨時(shí)表空間是Oracle數(shù)據(jù)庫(kù)的重要組成部分，盡管該部分并沒有cont體系結(jié)構(gòu)上得以展現(xiàn)，但其重要地位也是不容忽視的。尤其是
對(duì)于大型的頻繁操作，如創(chuàng)建索引，排序等等都需要在臨時(shí)表空間完成來減少內(nèi)存的開銷。當(dāng)然對(duì)于查詢性能要求較高的應(yīng)盡可能的避免在磁盤
上完成這些操作。本文主要描述的是臨時(shí)表空間的管理與受損恢復(fù)。

一、臨時(shí)表空間的特性與注意事項(xiàng)
??1.特性
????? ?用戶存儲(chǔ)臨時(shí)數(shù)據(jù)的表空間
?????? 臨時(shí)數(shù)據(jù)通常只在一個(gè)數(shù)據(jù)庫(kù)會(huì)話期間內(nèi)存在的數(shù)據(jù)，分為兩種形式，排序數(shù)據(jù)和全局臨時(shí)表
????? ?臨時(shí)數(shù)據(jù)不會(huì)被寫入存儲(chǔ)永久對(duì)象的普通表空間內(nèi)，而是存儲(chǔ)在臨時(shí)表空間的臨時(shí)段中
?????? 臨時(shí)表空間臨時(shí)性導(dǎo)致不需要備份該類型的表空間，RMAN也不支持對(duì)臨時(shí)表空間的備份
?????? 對(duì)于臨時(shí)數(shù)據(jù)的處理，不會(huì)生成重做，也不會(huì)生成撤銷數(shù)據(jù)
?????? 臨時(shí)表空間的數(shù)據(jù)文件不能置為只讀、不能重命名
?????? 監(jiān)時(shí)表空間的數(shù)據(jù)文件的日志方式總是NOLOGGING
?????? 使用臨時(shí)表空間的主要操作
??????? CREATE INDEX,ALTER INDEX ...REBUILD,ORDER BY,GROUP BY,DISTINCT,UNION,INTERSECT,MINUS,SORT-MERGER,JOIN,ANALYZE
??????
??2.臨時(shí)表空間使用的注意事項(xiàng)
????? ?a. 每個(gè)用戶都有一個(gè)缺省的臨時(shí)表空間，對(duì)于臨時(shí)表空間使用較高的系統(tǒng)，建議將臨時(shí)表空間數(shù)據(jù)文件分布到不同的磁盤
?????? b. 對(duì)于大型操作頻繁,(大型查詢,大型分類查詢,大型統(tǒng)計(jì)分析等),應(yīng)指定單獨(dú)的臨時(shí)表空間,以方便管理
?????? c. 分配用戶單獨(dú)臨時(shí)表空間,一般是針對(duì)大型產(chǎn)品數(shù)據(jù)庫(kù),OLTP數(shù)據(jù)庫(kù),數(shù)據(jù)庫(kù)倉(cāng)庫(kù)
?????? d. 對(duì)于小型產(chǎn)品不需要單獨(dú)制定臨時(shí)表空間,使用默認(rèn)臨時(shí)表空間
?????? e. 對(duì)于臨時(shí)表空間建議關(guān)閉自動(dòng)擴(kuò)展功能，避免過度擴(kuò)展所致的空間壓力?
??關(guān)于臨時(shí)表空間的創(chuàng)建與管理請(qǐng)參考： Oracle 表空間與數(shù)據(jù)文件
二、臨時(shí)表空間的管理
??1. 查看缺省的臨時(shí)表空間

SQL> select property_name,property_value from database_properties 2 where property_name like 'DEFAULT%'; PROPERTY_NAME PROPERTY_VALUE ------------------------------ -------------------------------- DEFAULT_TEMP_TABLESPACE TEMP DEFAULT_PERMANENT_TABLESPACE USERS DEFAULT_TBS_TYPE SMALLFILE

??2.查看臨時(shí)表空間的大小及位置????

SQL> select s.name tbsname,t.name,(t.bytes/1024/1024) bytes,status 2 from v$tablespace s,v$tempfile t 3 where s.ts# = t.ts#; TBSNAME NAME BYTES STATUS ---------- --------------------------------------------- ---------- ------- TEMP /u01/app/oracle/oradata/orcl/temp01.dbf 30 ONLINE SQL> select tablespace_name,file_name,bytes/1024/1024 Size_MB from dba_temp_files; TABLESPACE FILE_NAME SIZE_MB ---------- --------------------------------------------- ---------- TEMP /u01/app/oracle/oradata/orcl/temp01.dbf 30 SQL> select tablespace_name,logging,allocation_type 2 from dba_tablespaces where tablespace_name='TEMP'; TABLESPACE LOGGING ALLOCATIO ---------- --------- --------- TEMP NOLOGGING UNIFORM

??3. 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 /1024) "Used (G)" FROM v$sort_usage GROUP BY tablespace) t2 WHERE t1."Tablespace" = t2.tablespace(+); Tablespace Total (G) Used(G) Free (G) ------------------------------ --------------- ---------- ---------- GOEX_TEMP 31.999 1 30.999 FIX_TEMP 0.098 0 .098 TEMP 0.195 0 .195

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

-->使用臨時(shí)段的SQL語句 SELECT sess.SID, segtype, blocks * 8 / 1000 "MB", sql_text FROM v$sort_usage sort, v$session sess, v$sql SQL WHERE sort.SESSION_ADDR = sess.SADDR AND SQL.ADDRESS = sess.SQL_ADDRESS ORDER BY blocks DESC; -->下面的查詢也可以查詢誰正在使用臨時(shí)段 col username format a15 col machine format a15 col program format a30 col tablespace format a15 set linesize 160 SELECT s.username ,s.sid ,s.serial# ,s.sql_address ,s.machine ,s.program ,su.tablespace ,su.segtype ,su.contents FROM v$session s, v$sort_usage su WHERE s.saddr = su.session_addr; SELECT 'the ' || NAME || ' temp tablespaces ' || tablespace_name || ' idle ' || round(100 - (s.tot_used_blocks / s.total_blocks) * 100, 3) || '% at ' || to_char(SYSDATE, 'yyyymmddhh24miss') FROM (SELECT d.tablespace_name tablespace_name, nvl(SUM(used_blocks), 0) tot_used_blocks, SUM(blocks) total_blocks FROM v$sort_segment v, dba_temp_files d WHERE d.tablespace_name = v.tablespace_name(+) GROUP BY d.tablespace_name) s, v$database;

???3. 修改默認(rèn)的臨時(shí)表空間
???????? ??alter database default temporary tablespace tablespace_name;
???4. 對(duì)于過度使用臨時(shí)表空間，在允許的情況下，可以殺掉其session
????????? ?alter system kill session 'sid,serial#';??
???
三、臨時(shí)表空間故障
??前面已提到，臨時(shí)表空間不需要備份，如果對(duì)臨時(shí)表空間備份將收到錯(cuò)誤提示??

SQL> alter tablespace temp begin backup; alter tablespace temp begin backup * ERROR at line 1: ORA-03217: invalid option for alter of TEMPORARY TABLESPACE SQL> alter temporary tablespace temp begin backup; alter temporary tablespace temp begin backup * ERROR at line 1: ORA-00940: invalid ALTER command

??臨時(shí)表空間出錯(cuò)的錯(cuò)誤提示(位于告警日志中alert_orcl.log)
???Errors in file /u01/app/oracle/admin/orcl/bdump/orcl_dbw0_2230.trc:
???ORA-01186：file 3 failed verification tests
???ORA-01157：cannot identify/lock data file 3 - see DBWR trace file
???ORA-01110：data file 3:'/u01/app/oracle/oradata/orcl/temp01.dbf'
?
四、還原受損的臨時(shí)表空間
??1. 在session 1中刪除臨時(shí)表空間的數(shù)據(jù)文件

SQL> show user; USER is "SYS" SQL> ho rm /u01/app/oracle/oradata/orcl/temp01.dbf SQL> alter system checkpoint; -->執(zhí)行檢查點(diǎn)進(jìn)程 System altered.

??2. 在session 2中執(zhí)行排序查詢，提示臨時(shí)數(shù)據(jù)文件錯(cuò)誤???

SQL> show user; USER is "SCOTT" SQL> set autotrace traceonly; SQL> select owner,object_name from big_table order by id,owner,object_name; select owner,object_name from big_table order by id,owner,object_name * ERROR at line 1: ORA-01565: error in identifying file '/u01/app/oracle/oradata/orcl/temp01.dbf' ORA-27037: unable to obtain file status Linux Error: 2: No such file or directory Additional information: 3

??3. 在session 1中為臨時(shí)表空間增加數(shù)據(jù)文件??

SQL> alter tablespace temp add tempfile '/u01/app/oracle/oradata/orcl/temp02.dbf' 2 size 30m autoextend on next 1m maxsize 2g; Tablespace altered.

??4. 在session 2中繼續(xù)執(zhí)行排序操作，此次執(zhí)行成功??

SQL> select owner,object_name from big_table order by id,owner,object_name; 1000000 rows selected.

??5. 查詢臨時(shí)數(shù)據(jù)文件狀態(tài)及文件存在性?

SQL> set linesize 160 --> session 1中查看臨時(shí)數(shù)據(jù)文件狀態(tài),大小為0，但仍然為online狀態(tài) SQL> select s.name tbsname,t.name,(t.bytes/1024/1024) bytes,t.status 2 from v$tablespace s,v$tempfile t 3 where s.ts# = t.ts#; TBSNAME NAME BYTES STATUS -------------------- --------------------------------------------- ---------- ------- TEMP /u01/app/oracle/oradata/orcl/temp01.dbf 0 ONLINE TEMP /u01/app/oracle/oradata/orcl/temp02.dbf 30 ONLINE SQL> ho ls /u01/app/oracle/oradata/orcl/temp01.dbf ls: /u01/app/oracle/oradata/orcl/temp01.dbf: No such file or directory

??6. 清除控制文件內(nèi)記錄的不存在的臨時(shí)文件信息?

SQL> alter tablespace temp drop tempfile '/u01/app/oracle/oradata/orcl/temp01.dbf'; Tablespace altered.

??7. 基于表空間級(jí)別的恢復(fù)操作(下面給出主要步驟，不在演示)
?????? a. 創(chuàng)建一個(gè)新的臨時(shí)表空間
???? ??b. 使用alter database 將用戶切換到新的臨時(shí)表空間，即設(shè)置新的默認(rèn)的臨時(shí)表空間
????? ?c. 刪除受損的臨時(shí)表空間
??

臨時(shí)表空間的管理與受損恢復(fù)