Strange Overall Average Behavior

[silentfilm (Bruce Calvert)]

I've got a line chart that displays the average of a certain value and the Average of the Averages. This seems to display correctly.

However, if I add an additional filter to the overall average line to exclude zero values, then the Average of Averages is much higher than any of the values displayed. The overall average can't be higher than any of the values!

Am I missing something? I can't find anything on the Overall Average aggregation in the online documentation.

[bhavyarm]

@Marta_Bondyra could you please take a look at this?

Thanks,
Bhavya

[Marta_Bondyra]

Hi Bruce,
may I ask how your data for this particular time range looks like? The results might be correct if there's a lot of 0s or negative values. Take a look at this example dataset. For each timestamp, I created 2 data values and then run some excel formulas to get average , overall average and overall average including the values > 0.

[silentfilm (Bruce Calvert)]

Yes, about 40% of the minute averages are zero. There are no negative values.

I'm working on a different system but with the same version of Kibana and if the timeline is less than four hours the Average of Averages is correctly below the peaks of the displayed averages for every minute. That was what was displaying incorrectly in my original post.

If I set the timeline to 4+ hours then Kibana aggregates my data into 5-minute time periods and again the "Median Average" is shown on the chart is much higher than any individual average.

It looks like a bug but I decided to not use the "mean > 0" filter because that is more accurate, especially when the time period is 4+ hours and the minute values are aggregated into 5-minute values, the chart will correctly show the Average average over that time span.