ent;
System altered.
ZLM@ora10g> select group#,thread#,status,archived from v$log;
GROUP# THREAD# STATUS ARC ---------- ---------- ---------------- --- 1 1 ACTIVE YES 2 1 INACTIVE YES 3 1 CURRENT NO
--正常关闭数据库 ZLM@ora10g> shutdown immediate ORA-01031: insufficient privileges ZLM@ora10g> conn / as sysdba Connected. SYS@ora10g> shutdown immediate Database closed. Database dismounted. ORACLE instance shut down. SYS@ora10g>
--OS上删除current的在线日志文件redo03.log [oracle@ora10g ~]$ cd /u01/app/oracle/oradata/ora10g [oracle@ora10g ora10g]$ ls -l total 1461348 -rw-r----- 1 oracle oinstall 7520256 Jun 24 11:03 control01.ctl -rw-r----- 1 oracle oinstall 7520256 Jun 24 11:03 control02.ctl -rw-r----- 1 oracle oinstall 7520256 Jun 24 11:03 control03.ctl -rw-r----- 1 oracle oinstall 104865792 Jun 24 11:03 example01.dbf -rw-r----- 1 oracle oinstall 172032 Nov 29 2014 indx01.dbf -rw-r----- 1 oracle oinstall 52429312 Jun 24 11:02 redo01.log -rw-r----- 1 oracle oinstall 52429312 Jun 24 10:49 redo02.log -rw-r----- 1 oracle oinstall 52429312 Jun 24 11:03 redo03.log -rw-r----- 1 oracle oinstall 283123712 Jun 24 11:03 sysaux01.dbf -rw-r----- 1 oracle oinstall 587210752 Jun 24 11:03 system01.dbf -rw-r----- 1 oracle oinstall 52436992 Jun 23 16:17 temp01.dbf -rw-r----- 1 oracle oinstall 173023232 Jun 24 11:03 undotbs01.dbf -rw-r----- 1 oracle oinstall 41951232 Jun 24 11:03 users01.dbf -rw-r----- 1 oracle oinstall 100671488 Jun 24 11:03 zlm01.dbf [oracle@ora10g ora10g]$ rm -f redo03.log [oracle@ora10g ora10g]$ ls -l redo* -rw-r----- 1 oracle oinstall 52429312 Jun 24 11:02 redo01.log -rw-r----- 1 oracle oinstall 52429312 Jun 24 10:49 redo02.log [oracle@ora10g ora10g]$
--启动数据库 SYS@ora10g> startup ORACLE instance started.
Total System Global Area 524288000 bytes Fixed Size 1220384 bytes Variable Size 322961632 bytes Database Buffers 197132288 bytes Redo Buffers 2973696 bytes Database mounted. ORA-00313: open failed for members of log group 3 of thread 1 ORA-00312: online log 3 thread 1: '/u01/app/oracle/oradata/ora10g/redo03.log'
由于启动数据库会检查所有的文件，读取到在线日志文件redo03.log时，就报错了，因为已经被删除
--还原数据库 SYS@ora10g> recover database until cancel; Media recovery complete. SYS@ora10g> alter database open; alter database open * ERROR at line 1: ORA-01589: must use RESETLOGS or NORESETLOGS option for database open
由于之前是正常关闭数据库，在线日志的内容已经写到归档日志文件，利用归档日志进行还原，而还原后的数据库，必须用resetlogs方式来OPEN数据库
SYS@ora10g> alter database open resetlogs;
Database altered.
SYS@ora10g> conn zlm/zlm Connected. ZLM@ora10g> select count(*) from t1;
COUNT(*) ---------- 20
ZLM@ora10g> 只要是正常关闭数据库的，并且开启了归档，那么即便是删除了current的在线日志，也是可以将数据库重新打开的，并且不会丢失数据（由归档来保证）
测试3：非正常关闭数据库，并删除当前在线日志文件
--添加测试数据后，abort方式关闭数据库 ZLM@ora10g> select group#,thread#,status,archived from v$log;
GROUP# THREAD# STATUS ARC ---------- ---------- ---------------- --- 1 1 CURRENT NO 2 1 UNUSED YES 3 1 INACTIVE YES
ZLM@ora10g> insert into t1 select * from dba_objects where rownum<11;
10 rows created.
ZLM@ora10g> select count(*) from t1;
COUNT(*) ---------- 30
ZLM@ora10g> alter system archive log current;
System altered.
ZLM@ora10g> select group#,thread#,status,archived from v$log;
GROUP# THREAD# STATUS ARC ---------- ---------- ---------------- --- 1 1 ACTIVE YES 2 1 CURRENT NO 3 1 INACTIVE YES
ZLM@ora10g> shutdown abort ORA-01031: insufficient privileges ZLM@ora10g> conn / as sysdba Connected. SYS@ora10g> shutdown abort ORACLE instance shut down. SYS@ora10g>
--O |