Configure history recovery

The RDBMS adapter supports the following data collection modes which you configure in the DataCollectionMode parameter of your adapter's data source configuration:

• CurrentOnly: The adapter component operates normally. History recovery is disabled.

• CurrentWithBackfill (Default): The adapter component operates normally, but disconnections and shutdown events are recorded in the form of recovery intervals. When the adapter is reconnected to a data source, it automatically backfills data for the recorded intervals.

• HistoryOnly: The adapter component does not get started. The adapter is able to start collecting historical data on demand.

History recovery for adapters supports the following two operations related to the data collection mode:

• On demand history recovery: Recovers data from a specified start time or start and end time. If end time is not specified, the default is utcnow. On demand history recovery is available only when the adapter is in HistoryOnly data collection mode.

• Limited automatic history recovery: Automatically recovers up to four days of historical data lost due to connection disruptions, data source issues, or adapter shutdowns. Available only when the adapter is configured to use the CurrentWithBackfill data collection mode

By default, the adapter does not record multiple events sharing the same timestamp. The first event with a unique timestamp is saved, while any subsequent duplicate events are rejected. During history recovery, an existing event is overwritten if a new event arrives with the same timestamp.

However, you can configure the OMFCreateMode setting in PI Web API to add duplicate events instead of replacing them during history recovery. For additional information on configuring the OMFCreateMode setting, see Set behavior for duplicate data values in the PI Web API guide.

This behavior is fixed for events sent to CONNECT data services and cannot be configured.