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 Recovering a Database Instance 

Use

When you recover a database instance, you import backups and recover the database status that they contain. To do so, you first import a complete data backup, followed by the related log backups. You can use the option UNTIL to specify the time up to which the log backups are to be imported from the backup medium.

If the log volumes for the database instance are available and undamaged and still contain the log from the time of the complete data backup, use the command recover_start only to import the complete data backup. Then start the database instance and create the database instance from the log volume of the database instance (see also: Transferring to the ONLINE Operational State). If you specify the option -u | -until, you recover the database instance up to the specified time.

If you used an external backup tool to make these backups, use that tool to recover the database instance. Proceed as described in Restoring with External Backup Tools. Otherwise, use the description of the command recover_start, below.

The reply to this command gives you information about the import of the backup. However, you see this information only if the backup has been imported completely, or if the backup was interrupted. This command may, therefore, take a long time to execute.

If automatic log backups were activated before the recovery was started, they are not reactivated automatically after the recovery.

To reactivate the log backups, execute the command for activating automatic log backups.

Prerequisites

You have the DBM operator authorization Recovery.

You have opened a database session (Opening a Database Session).

Syntax

recover_start <medium> <type> [ExternalBackupID <external_backup_ID>] [<nnn>] [UNTIL <date> <time>] [AUTOIGNORE]

<medium>

Backup medium from which you want to import the backup.
When you restore a backup made on multiple parallel backup media (a parallel backup), enter the name of the media group here.

<type>

Type of backup to be imported: DATA (complete data backup), PAGES (incremental data backup), or LOG (log backup)

Options

ExternalBackupID <external_backup_ID>

To restore a backup created with an external backup tool, enter a backup ID here that the external backup tool can recognize as the backup.

<nnn>

Actual backup version on the backup medium that you want to read; relevant only for media of type FILE.

UNTIL <date> <time>
<date> ::= <yyyymmdd>
<time> ::= <hhmmss>

You can specify a time (year, month, day, hour, minutes, seconds) up to which you want to import log backups.

AUTOIGNORE

In the case of a parallel restore, the process is automatically continued by the system (Continuing a Parallel Restore).

To avoid receiving error messages, note the media naming conventions (see Defining or Changing a Backup Medium).

Logging on to the database manager CLI as operator DBM with password DBM, opening a database session with the database instance myDB, recovering the database instance from the backup created with Networker on the backup medium NSRPages (complete data backup type with the external backup ID 9025):

dbmcli –u dbm,dbm –uDBS –d myDB recover_start NSRPages DATA ExternalBackupID 9025

 

Reply

OK<NL>
Return code              <value><NL>
Date                    [<value>]<NL>
Time                    [<value>]<NL>
Server                  [<value>]<NL>
Database                [<value>]<NL>
Kernel Version          [<value>]<NL>
Pages Transferred       [<value>]<NL>
Pages Left              [<value>]<NL>
Volumes                 [<value>]<NL>
Medianame               [<value>]<NL>
Location                [<value>]<NL>
Error text              [<value>]<NL>
Label                   [<value>]<NL>
Is Consistent           [<value>]<NL>
First LOG Page          [<value>]<NL>
Last LOG Page           [<value>]<NL>
DB Stamp 1 Date         [<value>]<NL>
DB Stamp 1 Time         [<value>]<NL>
DB Stamp 2 Date         [<value>]<NL>
DB Stamp 2 Time         [<value>]<NL>
Page Count              [<value>]<NL>
Devices Used            [<value>]<NL>
Database ID             [<value>]<NL>
Max Used Data Page      [<value>]<NL>

Values for the Individual Fields of the Reply

Date

Date

Time

Time

Server

Name of the database server

Database

Name of the database instance

Kernel Version

Database kernel version

Pages Transferred

Number of pages transferred

Pages Left

Number of pages still to be transferred

Volumes

Number of backup media used

Medianame

Name of the backup medium

Location

File or device name

Errortext

Error message text

Label

Backup ID

Is Consistent

Only for data backup: backup is internally consistent

First LOG Page

For data backup: First page of the log backup to be read

For log backup: first page saved in log

Last LOG Page

Only for log backup: last page saved in log

DB Stamp 1 Date
DB Stamp 1 Time

Time stamp for first page of log backup

DB Stamp 2 Date
DB Stamp 2 Time

Time stamp for last page of log backup

Page Count

Total number of pages saved

Devices Used

Number of backup devices used

Database ID

Database ID used to identify data and log backups that belong together

Max Used Data Page

Maximum page number (indication of minimum database size when backup is imported)

Reply in the Event of an Error

If an error occurs while you are using an external backup tool, you receive a reply in the following format:

ERR<NL>
<errcode>, <err_description><NL>
[<extended_description><NL>]

<errcode>

Error message number

See also: Messages

<err_description>

Description of the error

<extended_description>

Cause of the error

 

The following errors may occur:

<errcode>

<err_description>

Explanation

-24927

ERR_TOOLCHK: the external backup tool was not found

The external backup tool could not be found or has been installed incorrectly.

-24926

ERR_MEDIUMCHK: the medium cannot be used with an external backup tool

The specified backup medium cannot be used with the backup tool to which the medium name refers (Defining and Changing a Backup Medium).

-24925

ERR_PREPARE: prepare of the backup operation failed

The preparations necessary to use the backup tool were not made correctly.

-24924

ERR_DBREQ: cannot start database kernel request

The database instance was unable to start the restore operation.

-24923

ERR_TOOLREQ: cannot start external backup tool correctly

The backup tool could not be started correctly.

-24922

ERR_OPCHK: cannot check state of backup operation

Unable to check the status of the database instance or the backup tool.

-24921

ERR_POSTOP: cannot finish backup operation correctly

Although the recovery was successful, the post-processing steps required could not be performed.

-24920

ERR_BACKUPOP: backup operation was unsuccessful

The recovery failed due to a problem with the database or the backup tool.

-24919

ERR_CLEANUP: cannot clean up correctly after backup operation

Although the recovery was successful, the temporary system resources used could not be freed up again.

 

 

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