Stacking Area Charts show inaccurate values (4246861)

When the Timeline slider is moved in such a way that the end time of the selected timeline is after the current time (in future), the chart shows a reading at the next measurement point which is in future. The chart also shows an additional time slice that displays the following message when hovering the mouse over the end of that chart's time axis :

"Context switches: Data missing @current_time".

On exporting data to Excel, we can see that data has been pulled up to the current time.

The chart’s time axis covers only the current time range. If the current time range goes into the future hence so does the chart’s time axis.

Stacking charts internally modify the time range to ensure a reasonable granularity so that data from multiple metrics will line up. For this reason, as an example, if the current time is 15:26 you will see a time slice ending at 15:30 even though the current time is 15:26. There was likely data collected at some point between 15:25 and 15:30, and so ends up in that time slice, which is graphed at the end point of the time slice.

The additional time slice indicates that Foglight is sending the chart empty time slices, probably due to the forced granularity applied by the chart and because there is no data at those times. There’s an open issue WCF-10450 to have the stacking area charts better handle these unexpected empty time slices.

Exported data in Foglight v5.5.8 matches the raw data, not the granular data graphed by the stacking area and bar charts. This has been fixed this in the Waverider release (v5.6.2) to bring exported data in line with what is actually shown on the chart.