Deploy and undeploy attributes

When an object is deployed with historical attributes, the history feature causes dynamic reconfiguration of the Historian. Each history feature causes a new tag to be created and configured automatically in the Historian at deployment time. The Historian storage system that will be used is determined by the configuration of the host engine object.

This dynamic configuration causes appropriate row/column configuration in the Historian schema.

If the connection to the Historian is down at deploy time, the attempt to dynamically reconfigure Historian is achieved when the connection is restored. In other words, automatic retry is built in. However, any data generated by the object during the time between deployment and the recovery is lost and cannot be recovered by store forward.

When an object configured for history is redeployed, changes to an object’s attributes makes the historian reconfigure storage. For example, if the engineering units string of an object changes from "Deg F" to "Deg C" when the object is redeployed, the Historian configuration database shows the change.

When an object configured for history is undeployed, all history remains in the Historian. The history data can be viewed in the future even if the object is no longer deployed.