_no_recovery_through_resetlogs参数功能探讨

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标题:_no_recovery_through_resetlogs参数功能探讨

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_no_recovery_through_resetlogs参数默认值和描述

SQL> select a.ksppinm name,b.ksppstvl value,a.ksppdesc description
  2    from x$ksppi a,x$ksppcv b
  3   where a.inst_id = USERENV ('Instance')
  4     and b.inst_id = USERENV ('Instance')
  5     and a.indx = b.indx
  6     and upper(a.ksppinm) LIKE upper('%&param%')
  7  order by name
  8  /
Enter value for param: _no_recovery_through_resetlogs
old   6:    and upper(a.ksppinm) LIKE upper('%&param%')
new   6:    and upper(a.ksppinm) LIKE upper('%_no_recovery_through_resetlogs%')

NAME                             VALUE                    DESCRIPTION
-------------------------------- ------------------------ --------------------------------------------
_no_recovery_through_resetlogs   FALSE                    no recovery through this resetlogs operation

大家知道在10gr2版本及其以后版本,大家知道默认情况下,可以实现跨resetlogs恢复数据库.通过该参数的描述可以看出,该参数的用途是使得resetlogs之后不能继续进行恢复(我的理解是以前的备份不能应用resetlogs后的归档日志)
在实际中该函数的作用是否和该参数的描述相符,我们通过试验验证

rman备份数据库

[oracle@xifenfei tmp]$ rman target /

Recovery Manager: Release 10.2.0.4.0 - Production on Thu Aug 30 11:51:49 2012

Copyright (c) 1982, 2007, Oracle.  All rights reserved.

connected to target database: XFF (DBID=3440302261)

RMAN> backup database format '/u01/oracle/oradata/tmp/10g_db_%U';

Starting backup at 30-AUG-12
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=143 devtype=DISK
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00001 name=/u01/oracle/oradata/XFF/system01.dbf
input datafile fno=00003 name=/u01/oracle/oradata/XFF/sysaux01.dbf
input datafile fno=00002 name=/u01/oracle/oradata/XFF/undotbs01.dbf
input datafile fno=00004 name=/u01/oracle/oradata/XFF/users01.dbf
channel ORA_DISK_1: starting piece 1 at 30-AUG-12
channel ORA_DISK_1: finished piece 1 at 30-AUG-12
piece handle=/u01/oracle/oradata/tmp/10g_db_0anjuhve_1_1 tag=TAG20120830T115214 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:01:35
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
including current control file in backupset
including current SPFILE in backupset
channel ORA_DISK_1: starting piece 1 at 30-AUG-12
channel ORA_DISK_1: finished piece 1 at 30-AUG-12
piece handle=/u01/oracle/oradata/tmp/10g_db_0bnjui2d_1_1 tag=TAG20120830T115214 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:03
Finished backup at 30-AUG-12

resetlogs打开数据库

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.

Total System Global Area  318767104 bytes
Fixed Size                  1267236 bytes
Variable Size             100665820 bytes
Database Buffers          209715200 bytes
Redo Buffers                7118848 bytes
Database mounted.

SQL> recover database until cancel;
Media recovery complete.
SQL> alter database open resetlogs;

Database altered.

创建测试表

SQL> create table t_xifenfei01
  2  as
  3  select * from dba_tables;

Table created.

SQL> create table t_xifenfei02
  2  as
  3  select * from dba_objects;

Table created.

SQL>  alter system switch logfile;

System altered.

SQL> /

System altered.

SQL> create table t_xifenfei03 
  2  as
  3  select * from dba_objects;

Table created.

SQL> alter system switch logfile;

System altered.

SQL> /

System altered.

恢复数据库

SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.

[oracle@xifenfei XFF]$ rm *.dbf
[oracle@xifenfei XFF]$ rman target /

Recovery Manager: Release 10.2.0.4.0 - Production on Thu Aug 30 12:00:47 2012

Copyright (c) 1982, 2007, Oracle.  All rights reserved.

connected to target database (not started)

RMAN> startup mount

Oracle instance started
database mounted

Total System Global Area     318767104 bytes

Fixed Size                     1267236 bytes
Variable Size                100665820 bytes
Database Buffers             209715200 bytes
Redo Buffers                   7118848 bytes

RMAN> restore database;

Starting restore at 30-AUG-12
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=157 devtype=DISK


channel ORA_DISK_1: starting datafile backupset restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
restoring datafile 00001 to /u01/oracle/oradata/XFF/system01.dbf
restoring datafile 00002 to /u01/oracle/oradata/XFF/undotbs01.dbf
restoring datafile 00003 to /u01/oracle/oradata/XFF/sysaux01.dbf
restoring datafile 00004 to /u01/oracle/oradata/XFF/users01.dbf
channel ORA_DISK_1: reading from backup piece /u01/oracle/oradata/tmp/10g_db_0anjuhve_1_1
channel ORA_DISK_1: restored backup piece 1
piece handle=/u01/oracle/oradata/tmp/10g_db_0anjuhve_1_1 tag=TAG20120830T115214
channel ORA_DISK_1: restore complete, elapsed time: 00:00:55
Finished restore at 30-AUG-12

RMAN> recover database;

Starting recover at 30-AUG-12
using channel ORA_DISK_1

starting media recovery

archive log thread 1 sequence 7 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_7_790743352.dbf
archive log thread 1 sequence 8 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_8_790743352.dbf
archive log thread 1 sequence 9 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_9_790743352.dbf
archive log thread 1 sequence 10 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_10_790743352.dbf
archive log thread 1 sequence 1 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_1_792676624.dbf
archive log thread 1 sequence 2 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_2_792676624.dbf
archive log thread 1 sequence 3 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_3_792676624.dbf
archive log thread 1 sequence 4 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_4_792676624.dbf
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_7_790743352.dbf thread=1 sequence=7
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_8_790743352.dbf thread=1 sequence=8
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_9_790743352.dbf thread=1 sequence=9
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_10_790743352.dbf thread=1 sequence=10
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_1_792676624.dbf thread=1 sequence=1
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_2_792676624.dbf thread=1 sequence=2
media recovery complete, elapsed time: 00:00:06
Finished recover at 30-AUG-12

SQL> alter database open;

Database altered.

SQL> select table_name from user_tables where table_name like 'T_XIFENFEI0_';

TABLE_NAME
------------------------------
T_XIFENFEI01
T_XIFENFEI02
T_XIFENFEI03

证明10gr2确实可以跨resetlogs recover 日志恢复数据库

测试_no_recovery_through_resetlogs参数

SQL> create table t_xifenfei04 as
  2  select * from dba_objects;

Table created.

SQL> alter system set "_no_recovery_through_resetlogs"=true scope=spfile;

System altered.

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.

Total System Global Area  318767104 bytes
Fixed Size                  1267236 bytes
Variable Size             100665820 bytes
Database Buffers          209715200 bytes
Redo Buffers                7118848 bytes
Database mounted.
SQL> recover database until cancel;
Media recovery complete.
SQL> alter database open resetlogs;

Database altered.

SQL> create table t_xifenfei05 
  2  as
  3  select * from dba_objects;

Table created.

SQL> create table t_xifenfei06
  2  as
  3  select * from dba_objects;

Table created.

SQL> alter system switch logfile;

System altered.

SQL> /

System altered.

SQL> /

System altered.

SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.

[oracle@xifenfei XFF]$ rm *.dbf
[oracle@xifenfei XFF]$ rman target /

Recovery Manager: Release 10.2.0.4.0 - Production on Thu Aug 30 12:47:40 2012

Copyright (c) 1982, 2007, Oracle.  All rights reserved.

connected to target database (not started)

RMAN> startup mount;

Oracle instance started
database mounted

Total System Global Area     318767104 bytes

Fixed Size                     1267236 bytes
Variable Size                100665820 bytes
Database Buffers             209715200 bytes
Redo Buffers                   7118848 bytes

RMAN> restore database;

Starting restore at 30-AUG-12
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=157 devtype=DISK

channel ORA_DISK_1: starting datafile backupset restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
restoring datafile 00001 to /u01/oracle/oradata/XFF/system01.dbf
restoring datafile 00002 to /u01/oracle/oradata/XFF/undotbs01.dbf
restoring datafile 00003 to /u01/oracle/oradata/XFF/sysaux01.dbf
restoring datafile 00004 to /u01/oracle/oradata/XFF/users01.dbf
channel ORA_DISK_1: reading from backup piece /u01/oracle/oradata/tmp/10g_db_0anjuhve_1_1
channel ORA_DISK_1: restored backup piece 1
piece handle=/u01/oracle/oradata/tmp/10g_db_0anjuhve_1_1 tag=TAG20120830T115214
channel ORA_DISK_1: restore complete, elapsed time: 00:00:45
Finished restore at 30-AUG-12

RMAN> recover database;

Starting recover at 30-AUG-12
using channel ORA_DISK_1
starting media recovery

archive log thread 1 sequence 7 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_7_790743352.dbf
archive log thread 1 sequence 8 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_8_790743352.dbf
archive log thread 1 sequence 9 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_9_790743352.dbf
archive log thread 1 sequence 10 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_10_790743352.dbf
archive log thread 1 sequence 1 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_1_792676624.dbf
archive log thread 1 sequence 2 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_2_792676624.dbf
archive log thread 1 sequence 3 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_3_792676624.dbf
archive log thread 1 sequence 4 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_4_792676624.dbf
archive log thread 1 sequence 5 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_5_792676624.dbf
archive log thread 1 sequence 6 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_6_792676624.dbf
archive log thread 1 sequence 1 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_1_792679299.dbf
archive log thread 1 sequence 2 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_2_792679299.dbf
archive log thread 1 sequence 3 is already on disk as file /u01/oracle/oradata/XFF/archivelog/1_3_792679299.dbf
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_7_790743352.dbf thread=1 sequence=7
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_8_790743352.dbf thread=1 sequence=8
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_9_790743352.dbf thread=1 sequence=9
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_10_790743352.dbf thread=1 sequence=10
--第一次 resetlogs后的归档
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_1_792676624.dbf thread=1 sequence=1 
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_2_792676624.dbf thread=1 sequence=2
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_3_792676624.dbf thread=1 sequence=3
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_4_792676624.dbf thread=1 sequence=4
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_5_792676624.dbf thread=1 sequence=5
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_6_792676624.dbf thread=1 sequence=6
--第二次 resetlogs后的归档(设置了_no_recovery_through_resetlogs参数为true并resetlogs后的归档日志
archive log filename=/u01/oracle/oradata/XFF/archivelog/1_1_792679299.dbf thread=1 sequence=1 
media recovery complete, elapsed time: 00:00:13
Finished recover at 30-AUG-12

RMAN> alter database open;

database opened

RMAN> exit


Recovery Manager complete.
[oracle@xifenfei XFF]$ sqlplus / as sysdba

SQL*Plus: Release 10.2.0.4.0 - Production on Thu Aug 30 12:49:46 2012

Copyright (c) 1982, 2007, Oracle.  All Rights Reserved.


Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> select table_name from user_tables where table_name like 'T_XIFENFEI0_';

TABLE_NAME
------------------------------
T_XIFENFEI01
T_XIFENFEI02
T_XIFENFEI03
T_XIFENFEI04
T_XIFENFEI05
T_XIFENFEI06

6 rows selected.

通过这里的测试证明使用_no_recovery_through_resetlogs=true后,resetlogs之后还是可以正常可以recover相关日志,证明_no_recovery_through_resetlogs参数不是限制这里的resetlogs后的归档日志应用,至于该参数的具体用途也希望知道的朋友告知下。但是这个参数在clone db和从rac db恢复到单实例db的时候,可能因为bug原因需要设置该参数为true,如:

--rac恢复到单实例RMAN Duplicate from RAC backup fails ORA-38856 [ID 334899.1]
sql>alter open database resetlogs;
ORA-38856: cannot mark instance UNNAMED_INSTANCE_2 (redo thread 2) as enabled
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