Database Reset (SAP Library - SAP Database Guide: Oracle (BC-DB-ORA-DBA))

Database Reset

Use

This section tells you about resetting your Oracle database after a failure. You normally need to do this if either of the following applies:

An error occurred in which all copies of the redo log files are lost, but the database file backup is available.
You performed a full offline backup immediately before the error, such as during a software upgrade.

With this function you can reset the database to a previous consistent state, at the time of either a full offline or a consistent online backup. If you reset from a full online backup, the consistent end point of the backup is used.

Prerequisites

We recommend you to:

Perform a full offline backup. If the database is running, use SAP tools, otherwise use operating system tools.

Back up all offline redo log files using BRARCHIVE. For more information, see -a|-archive.

It must be possible to set the database to status mount or open.

You have the following data available:

The BRBACKUP logs and the BRARCHIVE logs

The data file backups

If restoring from a consistent online backup, the accompanying redo log files

Features

Database Reset Using Full Offline Backup

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Database Reset Using Consistent Online Backup

This graphic is explained in the accompanying text

Activities

Database Reset Using Full Offline Backup

SAPDBA uses the BRBACKUP summary log file back<SID>.log and the corresponding detail logs to find the full offline backups.

SAPDBA saves the current online redo log files and the control files to the sapreorg directory. This is because these files are overwritten by the database reset. The database must be in the mount status for this step.

SAPDBA calls BRRESTORE to reset the database, overwriting the data files, control files, and online redo log files with the corresponding files from the offline backup.

SAPDBA restarts the database to status mount or open, depending on the option you selected at the start of the reset.

Database Reset Using Consistent Online Backup

SAPDBA uses the BRBACKUP summary log file back<SID>.log and the corresponding detail logs to find the consistent online backups.

SAPDBA saves the current online redo log files and the control files to the sapreorg directory. This is because these files are overwritten by the database reset. The database must be in the mount status for this step.

SAPDBA calls BRRESTORE to reset the database, overwriting the data files, control files, and online redo log files with the corresponding files from the online backup.

SAPDBA recovers the database until the consistent end point of the online backup. You cannot specify another point in time for this type of recovery.

SAPDBA restarts the database to status open, using the resetlogs option.

You must perform a full backup, since recovery after resetlogs is not possible.

You manually delete the offline redo log files that have been restored from the saparch directory.

Note

After a successful database reset with SAP tools, you might need to do some reworking, because the log tables SDBAH and SDBAD are affected. For more information, see Actions after a Partial Recovery.