Is there any documentation which throws light on how data aggregation happens in data warehouse grooming? what algorithm exactly it follows in different aggregation type (raw, hourly, daily)?

Question

Is there any documentation which throws light on how data aggregation happens in data warehouse grooming? what algorithm exactly it follows in different aggregation type (raw, hourly, daily)?
How exactly it picks up a specific data value during Hourly aggregations and Daily aggregations?As in  How the value is chosen. Does it say averages out or simply picks  value at the start of the hour/day or end of the hour/day ??

Answer 1

I'll try one more time. :)
Views in the operations console are derived from data in the operational database. This is always raw data, and typically does not go back more than 7 days.
Reports get data from the data warehouse. Unless you create a custom report that uses raw data, you will never see raw data in a report - Microsoft and probably all 3rd party vendors do not develop reports that fetch raw data.
Reports use aggregated data - hourly and daily. The data is aggregated by min, max, and avg sample for that particular aggregation. If it's hourly data, then you will see the min, max, and avg for that entire hour. Same goes for daily - you will see the
min, max, and avg data sample for that entire day.
And to try clarifying even more, the values you see plotted on the report are avg samples. If you drill into the performance detail report, then you can see the min, max, and avg samples, as well as standard deviation (which is calculated based on these
three values).
Jonathan Almquist | SCOMskills, LLC (http://scomskills.com)