As we continue up the stack, let's now take a look at some server performance metrics. How about an obvious web server metric? Enter prometheus_http_requests_total to get an idea of how many requests have been served so far:
Well, this is a bit of a mess. You can't see all 22 of the time series—they're all stacked on top of each other and there's a vague warning about something monotonically increasing. As we saw in the previous section, it's no problem to apply filters—say, to filter out the GET method handlers—but then we'd still have a stack of nearly 20 individual series.
Applying aggregations to our query data
If only there were some way to combine all the individual data series into one. It turns out there is, and it's called an aggregation. We can actually tell Prometheus to apply an aggregation function (in this case, sum) after...