SAND CDBMS Tools Reference Guide
Database Server (nserv)

 

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Shutting Down the Database Server


Shutdown Commands

As mentioned above, once a database server instance has been successfully started, the nserv process is no longer interactive. Therefore, server shutdown can be performed only from a client program. Once the server has been shut down, the nserv process returns control to the operating system.

Note:
Server shutdown can also be accomplished by pressing <Ctrl+C>. This method should be used only as a last resort, if the nserv program is not responding to client commands. Shutting down a database instance in this manner will cause uncommitted changes to be rolled back.

An nserv process can be shut down using the SHUTDOWN command from nisqlm SQL mode. There are two options for the timing of the shutdown operation:

The SHUTDOWN command can be executed only by a user with DBA privileges on the database.

For complete information about the SHUTDOWN command, consult the SAND CDBMS SQL Reference Guide.


Shutting Down nserv in Virtual Mode

When the nserv process running a secondary virtual instance is shut down, any changes made by users are discarded. In the case of the primary virtual instance only, the SQL SHUTDOWN command may include a KEEP CHANGE option to write changes made in Virtual Mode to the real database. When the SHUTDOWN...KEEP CHANGE command is executed, SAND CDBMS performs the following operations:

  1. The Temporary Delta File containing database changes is transformed into a permanent Update File.
  2. The database server instance is shut down.
  3. The database instance is automatically restarted with the -APPLY option to write the changes in the Update File to the real database.

For complete information about the SHUTDOWN...KEEP CHANGE command, consult the SAND CDBMS SQL Reference Guide. For more information about Virtual Mode, consult the Virtual Mode Operations section of the SAND CDBMS Administration Guide.


Shutting Down nserv in Persistent Mode

When the nserv process is running in Persistent mode, the SQL SHUTDOWN command may include a KEEP CHANGE option to preserve changes made to the current database snapshot. When the SHUTDOWN...KEEP CHANGE command is executed in Persistent Mode, the Temporary Delta File containing database changes is transformed into a permanent Time Travel Update File and the database snapshot number is increased by 1. Note that it is not possible to specify a user-defined name for the Time Travel Update File: if a 'change file' argument is included in the SHUTDOWN...KEEP CHANGE command in Persistent Mode, it is ignored.

For complete information about the SHUTDOWN...KEEP CHANGE command, consult the SAND CDBMS SQL Reference Guide. For more information about Persistent Mode, consult the Persistent Mode Operations section of the SAND CDBMS Administration Guide.

 

Previous Topic:
Managing Database Server Access
Chapter Index