Currently SolarIn tracks hourly audit metrics for datum I/O:

1. datum properties ingested
2. datum stored
3. datum queried

The datum properties metric is updated when new datum are inserted, but also when existing datum are updated. This is intentional, as the number of properties in a datum is dynamic and could change when updating an existing datum. It would be useful, however, to understand how many of those properties were inserted versus updated. A large update amount can indicate poor network connectivity or a configuration error in a node that is re-posting data it shouldn't be.

This ticket proposes to add a new audit metric for datum properties updated. The metric is a count of properties that were ingested and replaced an existing datum. With this new metric, the number of inserted properties could be derived as ingested - updated.