You can start a standby instance with the current dataset of the original instance or with the dataset as it was in the original instance at a particular point in time in the past.
To start the standby instance with the current dataset of the original instance, you stop the original instance, execute a final log backup in the original instance, import this log backup into the standby instance and then start the standby instance.
You can only start the standby instance with the dataset of the original instance as it was at a point in time in the past if, until now, the log backups that have been imported into the standby instance are from before the desired point in time.
When you import the log backups, you specify the point in time up to which you want the system to import the log entries. If you have the log backups from the original instance imported automatically into the standby instance, then cancel this operation now. Then you start the import of the log backups once again and specify the point in time up to which you want the system to import the log entries.
The system imports the log entries and asks you to specify the succeeding data carrier(s) until it has reached the log entries that were written at the specified point in time. At this point the system ends the import of the log entries and transfers the database instance to the ONLINE operational state.
If a problem with the original instance has made it impossible to execute a final log backup, but the log volumes of the original instance are still intact, you can use operating system commands to copy their contents to the volumes of the standby instance.
To read the
prerequisites, see Database Manager CLI, recover_cancel,
recover_start,
recover_replace
See also:
Setting Up and Updating Standby Instances
Copying Log Volumes with Operating System Commands
Concepts of the Database, Standby
Database
On the local computer you have a standby instance named TESTDB for the database instance DEMODB on computer GENUA. Using a script, the log backups created by DEMODB are automatically imported into TESTDB at defined intervals.
On February 2, 2006 at 16:36:10 there was a hardware error in the data area in DEMODB. So you decide to restore the standby instance TESTDB to its state on February 2, 2006 at 16:36:00 and start it in that state.
In the following section, explanations of the output are in bold print and marked as comments with the number sign (#).
...
1. The first step depends on whether you have, to this point, imported log backups into TESTDB automatically or manually.
○
If you have the log
backups from the original instance imported automatically into the standby
instance TESTDB, then cancel this operation now:
dbmcli on TESTDB>recover_cancel
OK
Returncode 0
Date
Time
Server
Database
Kernel Version
Pages Transferred 0
Pages Left 0
Volumes
Medianame
Location
Errortext
Label
Is Consistent
First LOG Page
Last LOG Page
DB Stamp 1 Date
DB Stamp 1 Time
DB Stamp 2 Date
DB Stamp 2 Time
Page Count 0
Devices Used
Database ID
Max Used Data Page
----
dbmcli on TESTDB>
Then transfer TESTDB to the ADMIN operational state:
dbmcli on TESTDB>db_admin
OK
○ If you have imported the log backups from DEMODB into TESTDB manually, you can now call the Database Manager CLI in session mode, log on as operator DBM with password DBM and connect to the standby instance TESTDB:
>dbmcli –u DBM,DBM –d TESTDB
dbmcli on TESTDB>
2. Open a database session:
dbmcli on TESTDB>db_connect
OK
3. Start the import of the missing log backups up to the desired point in time:
dbmcli on TESTDB>recover_start LogSave LOG 009 UNTIL 20060202 163600
OK
Returncode -8020
# The specified data carrier has been imported. Return code -8020 prompts you to specify the next data carrier.
Date 20060203
Time 00134353
Server GENUA
Database DEMODB
Kernel Version Kernel 7.6.00 Build 016-123-109-428
Pages Transferred 1168
Pages Left 0
Volumes 1
Medianame LogBackupFile
Location \\GENUA\Documents and Settings\All Users\Application Data\sdb\data\wrk\DEMODB\Backups 2005\Data\logBackupFeb.009
Errortext
Label LOG_000000009
Is Consistent
First LOG Page 17187
Last LOG Page 18452
DB Stamp 1 Date 20060202
DB Stamp 1 Time 00093758
DB Stamp 2 Date 20060202
DB Stamp 2 Time 00093819
Page Count 1265
Devices Used 1
Database ID GENUA:DEMODB_20060125_165646
Max Used Data Page
--
dbmcli on TESTDB>recover_replace LogBackupFile "C:\Documents and Settings\All Users\Application Data\sdb\data\wrk\DEMODB\Backups 2005\Data\logBackupFeb" 010
OK
Returncode -8020
# The specified data carrier has been imported. Return code -8020 prompts you to specify the next data carrier.
Date 20060203
Time 00134353
Server GENUA
Database DEMODB
Kernel Version Kernel 7.6.00 Build 016-123-109-428
Pages Transferred 2032
Pages Left 0
Volumes 1
Medianame LogBackupFile
Location \\GENUA\\Documents and Settings\All Users\Application Data\sdb\data\wrk\DEMODB\Backups 2005\Data\logBackupFeb.010
Errortext
Label LOG_000000010
Is Consistent
First LOG Page 18453
Last LOG Page 20670
DB Stamp 1 Date 20060202
DB Stamp 1 Time 00163233
DB Stamp 2 Date 20060202
DB Stamp 2 Time 00163447
Page Count 2217
Devices Used 1
Database ID GENUA:DEMODB_20060125_165646
Max Used Data Page
---
dbmcli on TESTDB>recover_replace LogBackupFile "\\GENUA\Documents and Settings\All Users\Application Data\sdb\data\wrk\DEMODB\Backups 2005\Data\logBackupFeb" 011
OK
Returncode 0
# The specified data carrier has been imported. Return code 0 tells you that all log entries that had been written up to the specified point in time have been imported.
Date 20060203
Time 00134353
Server GENUA
Database DEMODB
Kernel Version Kernel 7.6.00 Build 016-123-109-428
Pages Transferred 1280
Pages Left 0
Volumes 1
Medianame LogBackupFile
Location \\GENUA\Documents and Settings\All Users\Application Data\sdb\data\wrk\DEMODB\Backups.011
Errortext
Label LOG_000000011
Is Consistent
First LOG Page 20671
Last LOG Page 23024
DB Stamp 1 Date 20060202
DB Stamp 1 Time 00163601
DB Stamp 2 Date 20060202
DB Stamp 2 Time 00163604
Page Count 2353
Devices Used 1
Database ID GENUA:DEMODB_20060125_165646
Max Used Data Page
---
dbmcli on TESTDB>
The system has imported the log backups up to the specified point in time and subsequently transferred the database instance to the ONLINE operational state.
You can now operate the standby instance as the active instance.