Restoring a Database from Backups

Restoring a database includes a series of dump and load commands.

The figure below illustrates the process of restoring a database that is created at 4:30 p.m. on Monday and dumped immediately afterward. Full database dumps are made every night at 5:00 p.m. Transaction log dumps are made at 10:00 a.m., 12:00 p.m., 2:00 p.m., and 4:00 p.m. every day:

Graphic showing the steps performed for routine dumps during a typical day and the steps for restoring the database from a dump.

Use dump transaction with no_truncate to get a current transaction log dump
Use load database to load the most recent database dump, Tape 6. load database sets the database status to “offline.”
Use load transaction to apply the most recent transaction log dump, Tape 7.
Use online database to set the database status to “online.”

This figure illustrates how to restore the database when the data device fails at 4:59 p.m. on Tuesday—just before the operator is scheduled to make the nightly database dump:

Restoring a database, a second scenario
Graphic shows the order of dumps over a day and how a crash disrupts the work flow. After the crash, there is a dump transaction and a load database then a series of load database commands and the final online database.

Graphic shows the order of dumps over a day and how a crash disrupts the work flow. After the crash, there is a dump transaction and a load database then a series of load database commands and the final online database.

To restore the database:

Use dump transaction with no_truncate to get a current transaction log dump on Tape 6 (the tape you would have used for the routine database dump).
Use load database to load the most recent database dump, Tape 1. load database sets the database status to “offline.”
Use load transaction to load Tapes 2, 3, 4, and 5 and the most recent transaction log dump, Tape 6.
Use online database to set the database status to “online.”