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Saving a KB Snapshot File

You can save all of a KB's permanent and transient knowledge, including the real-time data associated with the G2 run-time environment, by saving a KB snapshot file.

To save a KB to a snapshot file:

Execute the g2-snapshot system procedure, as described in the G2 System Procedures Reference Manual.

The g2-snapshot system procedure writes the snapshot file with data as of the moment that it is invoked. It does this despite the fact that the task of writing the snapshot file allows interrupts for other processing. Thus, even if you modify or delete significant portions of a KB after invoking g2-snapshot, G2 writes that knowledge into the KB snapshot file as it existed at the time the procedure was invoked.

See Warmbooting a KB Snapshot File for information about how to load KB snapshot file and resume running a KB from it.

Contents of a KB Snapshot File

A KB snapshot file records:

All information necessary to present the KB as if it had been reset at the time of the snapshot, including information necessary to undo changes that are normally undone when a KB is reset
All transient items
The current values, collection times, expiration times, and histories of all variables and parameters when present
The simulation values and histories of all variables when present
The activation status of all KB workspaces
All instances of dynamic relations
The contents of all lists and arrays

The G2 Simulator, which can provide simulation values and simulation histories, is a superseded capability. For more information, see Appendix F, Superseded Practices.

A KB snapshot file does not record:

The current executing status of rules, button items and display items
Procedure invocations and their associated information
The Operator Logbook, the Message Board, menus, temporary workspaces, or tables, such as Inspect tables and attribute tables that have not been transferred to a workspace.

Naming Conventions for KB Snapshot Files

Snapshot filenames must include the .kb extension. In addition, you should follow naming conventions that distinguish snapshot files from KB files, such as including the suffix -snapshot in the filename. To identify the time at which the snapshot was saved, you might also prefer to include a timestamp in the filename, for example, monitoring-snapshot-29aug93-02-14-23.kb.

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