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Watch Those Aggregates

Ronald Dameron warns us about graphs in the Azure portal:

I would expect to see the CPU spike with the same value no matter what time range I selected. But, to see the spike that fired the alert, I had to to “Edit” the chart and select different time ranges to see the differences. It wasn’t until I selected a narrow custom time range that the CPU graph would display the CPU spike that corresponded to the alert firing. The alert fires if the CPU percentage exceeds 80% over 15 minutes. So, if you “know” something happened, try different time ranges but especially the custom range to find what you are looking for.

For your highbrow reference of the quarter, FA Hayek on John Maynard Keynes’s Treatise of Money:  “Mr. Keynes’s aggregates conceal the most fundamental mechanisms of change.”

This isn’t an Azure-specific problem; it’s something we have to think about whenever we aggregate data.