Opening the Database with the RESETLOGS Option
来源:互联网 发布:大数据bi 编辑:程序博客网 时间:2024/05/07 11:15
Opening the Database with the RESETLOGS Option
Whenever
you perform incomplete recovery or recovery with a backup control file,
you must reset the online logs when you open the database. The new
version of the reset database is called a new incarnation.
This section contains the following topics:
About Opening with the RESETLOGS Option
Executing the ALTER DATABASE OPEN Statements
Checking the Alert Log After a RESETLOGS Operation
About Opening with the RESETLOGS Option
The RESETLOGS
option is always required after incomplete media recovery or recovery using a backup control file. Resetting the redo log does the following:
Archives the current online redo logs (if they are accessible) and
then erases the contents of the online redo logs and resets the log
sequence number to 1. For example, if the current online redo logs are
sequence 1000 and 1001 when you openRESETLOGS
, then the database archives logs 1000 and 1001 and then resets the online logs to sequence 1 and 2.Creates the online redo log files if they do not currently exist.
Reinitializes the control file metadata about online redo logs and redo threads.
Updates all current datafiles and online redo logs and all subsequent archived redo logs with a new
RESETLOGS
SCN
and time stamp.
Because the database will not apply an archived log to a datafile unless the RESETLOGS
SCN
and time stamps match, the RESETLOGS
prevents you from corrupting datafiles with archived logs that are not
from direct parent incarnations of the current incarnation.
In prior releases, it was recommended that you back up the database immediately after the RESETLOGS
. Because you can now easily recover a pre-RESETLOGS
backup like any other backup, making a new database backup is optional.
In order to perform recovery through resetlogs you must have all
archived logs generated since the last backup and at least one control
file (current, backup, or created).
Figure 18-1
shows the case of a database that can only be recovered to log sequence
2500 because an archived redo log is missing. When the online redo log
is at sequence 4000, the database crashes. You restore the sequence
1000 backup and prepare for complete recovery. Unfortunately, one of
your archived logs is corrupted. The log before the missing log
contains sequence 2500, so you recover to this log sequence and open RESETLOGS
. As part of the RESETLOGS
, the database archives the current online logs (sequence 4000 and 4001) and resets the log sequence to 1.
You generate changes in the new incarnation of the database,
eventually reaching log sequence 4000. The changes between sequence
2500 and sequence 4000 for the new incarnation of the database are
different from the changes between sequence 2500 and sequence 4000 for
the old incarnation. You cannot apply logs generated after 2500 in the old incarnation to the new incarnation, but you can apply the logs generated before sequence 2500 in the old incarnation to the new incarnation. The logs from after sequence 2500 are said to be orphaned in the new incarnation because they are unusable for recovery in that incarnation.
Figure 18-1 Creating a New Database Incarnation
Description of "Figure 18-1 Creating a New Database Incarnation"
Executing the ALTER DATABASE OPEN Statements
To preserve the log sequence number when opening a database after media recovery, execute either of the following statements:
ALTER DATABASE OPEN NORESETLOGS;
ALTER DATABASE OPEN;
To reset the log sequence number when opening a database after
recovery and thereby create a new incarnation of the database, execute
the following statement:
ALTER DATABASE OPEN RESETLOGS;
If you open with the RESETLOGS
option, the database
returns different messages depending on whether recovery was complete
or incomplete. If the recovery was complete, then the following message
appears in the alert_
SID
.log
file:
RESETLOGS after complete recovery through change scn
If the recovery was incomplete, then this message is reported in the alert_
SID
.log
file, where scn
refers to the end point of incomplete recovery:
RESETLOGS after incomplete recovery UNTIL CHANGE scn
If you attempt to OPEN
RESETLOGS
when you
should not, or if you neglect to reset the log when you should, then
the database returns an error and does not open the database. Correct
the problem and try again.
See Also:
"About User-Managed Media Recovery Problems" for descriptions of situations that can cause
ALTER
DATABASE
OPEN
RESETLOGS
to failChecking the Alert Log After a RESETLOGS Operation
After opening the database with the RESETLOGS
option, check the alert_
SID
.log
to see whether the database detected inconsistencies between the data
dictionary and the control file, for example, a datafile that the data
dictionary includes but which is not listed in the new control file.
The following table describes two possible scenarios.
Datafile is listed
Datafile is not listed
References to the unlisted datafile are removed from the control file. A message in the alert log indicates what was found.
Datafile is not listed
Datafile is listed
The database creates a placeholder entry in the control file under
MISSING
nnnnn (where nnnnn is the file number in decimal). MISSING
nnnnn is flagged in the control file as offline and requiring media recovery. You can make the datafile corresponding to MISSING
nnnnn accessible by using ALTER
DATABASE
RENAME
FILE
for MISSING
nnnnn so that it points to the datafile. If you do not have a backup of this datafile, then drop the tablespace.本文转自
http://download.oracle.com/docs/cd/B19306_01/backup.102/b14191/osrecov009.htm
- Opening the Database with the RESETLOGS Option
- About Opening with the RESETLOGS Option
- start oracle with the linux opening
- DDL With the WAIT Option (DDL_LOCK_TIMEOUT) in Oracle Database 11g Release 1
- 181 You performed the RMAN database backup with the KEEP option. Which two statements are true about
- DDL With the WAIT Option (DDL_LOCK_TIMEOUT)
- Communicating with the Database (Using ADO)
- Working with the SQLite-Database - Cursors
- Fundamentals of Working with the Database
- WordPress Essentials: Interacting With The WordPress Database
- an error occurred while creating opening the c++ browsing database 解决办法
- an error occurred while creating opening the c++ browsing database 解决办法
- error opening the editor问题
- Option to use with setsockopt at the IPPROTO_IP level
- Some serious issues with the new -O option
- nobody cared (try booting with the "irqpoll" option)
- irq n: nobody cared (try booting with the "irqpoll" option)
- ORA-01589: must use RESETLOGS or NORESETLOGS option for database open
- 求子数组的最大和
- 转 >
- Servlet的生命周期
- 写在最前
- JAVA中的方法
- Opening the Database with the RESETLOGS Option
- vba 验证文本框中只输入数字
- Flex Builder 3 与 MyEclipse结合开发环境的搭建
- ASP.NET26个常用性能优化方法(转载)
- 求次大数
- 电子地图系统说明(目录)
- SQL SERVER性能优化综述
- C#中DataAdapter与DataReader的区别和联系(转载)
- 【架构案例】网站架构横向对比