Change the database-logging mode
You can use ondblog or ontape to add or change logging. Then use ON-Bar, or ontape to back up the data. When you use ON-Bar or ontape, the database server must be in online, administration, or quiescent mode.
You can use ondblog, ontape, or HCL® OneDB® Server Administrator (ISA) to add or change logging. Then use ON-Bar, or ontape to back up the data. When you use ON-Bar or ontape, the database server must be in online, administration, or quiescent mode.
For information about ON-Bar and ontape, see the HCL OneDB Backup and Restore Guide.
The
following table shows how the database server administrator can change
the database-logging mode. Certain logging mode changes take place
immediately, while other changes require a level-0 backup.
| Converting from: | Converting to no logging | Converting to unbuffered logging | Converting to buffered logging | Converting to ANSI compliant |
|---|---|---|---|---|
| No logging | Not applicable | Level-0 backup (of affected storage spaces) | Level-0 backup (of affected storage spaces) | Level-0 backup (of affected storage spaces) |
| Unbuffered logging | Yes | Not applicable | Yes | Yes |
| Buffered logging | Yes | Yes | Not applicable | Yes |
| ANSI compliant | Illegal | Illegal | Illegal | Not applicable |
Changing the database-logging mode has the following
effects:
- While the logging status is being changed, the database server places an exclusive lock on the database to prevent other users from accessing the database, and frees the lock when the change is complete.
- If a failure occurs during a logging-mode change, check the logging mode in the flags in the sysdatabases table in the sysmaster database, after you restore the database server data. For more information, see Monitor the logging mode of a database. Then try the logging-mode change again.
- If a failure occurs during a logging-mode change, check the logging mode in ISA or the flags in the sysdatabases table in the sysmaster database, after you restore the database server data. For more information, see Monitor the logging mode of a database. Then try the logging-mode change again.
- After you choose either buffered or unbuffered logging, an application can use the SQL statement SET LOG to change from one logging mode to the other. This change lasts for the duration of the session. For information about SET LOG, see the HCL OneDB Guide to SQL: Syntax.
- If you add logging to a database, the change is not complete until the next level-0 backup of all the storage spaces for the database.