Step and Resolution in Prometheus

[Peter Zaitsev]

Hi,

I originally posted this in Grafana mailing list thinking these are handled on Grafana size, it looks like it is done on  Prometheus side though, so Let me re-post it here

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When I edit graph for Prometheus Data Source I see "Step" and "Resolution" modifiers available;  Step  seems to be chosen based on zoom factor of the graph where Resolution defaults to 1/2 and can be changed.

It does not look like these are very clearly explained in the documentation, where I would really like to understand how exactly these will cause my time series displayed. 

Lets look example at this volatile time series  with samples evenly spaced 1 sec:

0,0,0,0,10,0,0,0,0,10,0,0,0,0,10

Basically assume some activity happens every 5 seconds.

How exactly Grafana will visualize it if  Step=5s and Resolution 1/2    ? Is it going to be just picking every 5th of the data points available possibly giving us all 0 or all 10s for the case above ?   Or will it compute average over the step interval so value should always be 2 in this case ?

When how does resolution comes in play ?

What I'm trying to do is get the graph which shows good smoothed average when I zoom out for example looking at data over 1 week, but if I zoom in to look at the data over last minute I can get second level of detail with all variations shown, as it can be important

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