History recovery

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

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

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

  If the BackfillHistoricalData property is set to true, AVEVA Events to CONNECT will backfill the data from the date time value specified in BackfillStartDateTime property.

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

History recovery for agents supports the following three 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 agent is in HistoryOnly data collection mode.

• Limited automatic history recovery: Backfills data gaps that originated from connection disruptions, data source issues, or AVEVA agent shutdown or both. This is limited to a maximum time-range of four days. Limited automatic history recovery is available only when the agent is in CurrentWithBackfill data collection mode.

• Limited backfill historical data: Backfills data up to 4 days old when BackfillHistoricalData property is set to true. The BackfillStartDateTime property is used to specify the interval the agent goes back to retrieve historical data.

  Only after the backfill is complete, will the scheduled data selection items be used by the agent for data collection. Limited backfill historical data is available only when the agent is in CurrentWithBackfill data collection mode. Also, once backfill is complete, the agent automatically disables BackfillHistoricalData so that further restarts of the agent will not backfill data multiple times.