Changing Database-Logging Status

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Changing Database-Logging Status

You can use ondblog to change logging and then use ON-Bar to back up the data. For information on ON-Bar, see the IBM Informix: Backup and Restore Guide.

Table 24 shows how the database server administrator can change the database-logging status. Certain logging status changes take place immediately while other changes require a level-0 backup.

Table 24. Logging Status Transitions
Converting from:	Converting to:
Converting from:	No Logging	Unbuffered Logging	Buffered Logging	ANSI Compliant
Unbuffered logging	Yes	Not applicable	Yes	Yes
Buffered logging	Yes	Yes	Not applicable	Yes
ANSI compliant	Illegal	Illegal	Illegal	Not applicable

Tip:

To change the logging status of ANSI-compliant databases, unload and reload the data. For more information, see Making a Database ANSI Compliant with ondblog.

Some general points about changing the database-logging status follow:

When you change the logging status, the database server places an exclusive lock on the database to prevent other users from accessing the database.
If a failure occurs during a logging-mode change, check the logging mode the flags in the sysdatabases table in the sysmaster database after you restore the database server data. For more information, see Monitoring Transaction Logging.
Once 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 on SET LOG, see the IBM Informix: Guide to SQL Syntax.
Databases always use transaction logging. You can specify what log-buffering mode they use. You also can turn logging on or off for tables.