The PingDataMetrics Server DBMS stores all historical sample data.
The data in the PingDataMetrics Server DBMS is continually changing as long as the PingDataMetrics Server is running.
The system that feeds data to the PingDataMetrics Server is designed to allow the PingDataMetrics Server to be offline for hours at a time without dropping any data. The collection points hold the data for hours, giving the PingDataMetrics Server time for maintenance tasks. The collection points do have a limit on how long they hold data, so the PingDataMetrics Server cannot be offline for an indeterminate time.
If the PingDataMetrics Server is offline so long that the collection points start to delete data that has not yet been captured, then there will be gaps in the data. Aggregation still works, even with these gaps. If the data gap is four hours, four time samples will be missing in the one hour aggregation level, and no data will be missing in the one day aggregation level. However, the one day aggregation level will use only 20 hours of data rather than 24. By default, the PingDataMetrics Server can be offline for about eight hours before any data is lost.
The PingDataMetrics Server responds to queries that result in data with time gaps. The resulting data differentiates between data with zero value and missing data.