Handle more arithmetic operators and aggregators for native histograms
This includes operators for multiplication (formerly known as scaling), division, and subtraction. Plus aggregations for average and the avg_over_time function.
Stdvar and stddev will (for now) ignore histograms properly (rather than counting them but adding a 0 for them).
Signed-off-by: Jeanette Tan <jeanette.tan@grafana.com>
* Provide a callout about the vector matching keywords and the group
modifiers.
Relates prometheus/docs#2106
Signed-off-by: Harold Dost <h.dost@criteo.com>
Sadly, just linking to the Histogram best practice document, as done
for `histogram_quantile`, would be confusing here because the best
practice document only deals with quantiles in the context of
Histograms and Summaries, which is very different from the context of
the `quantile` aggregator and `quantile_over_time` function, which is
already a source of a lot of confusion.
Thus, I think the least bad solution is to add a short explanation in
this section directly. There isn't even a good resource on the
internet we can link to. A lot of statisticians use φ-quantiles, but
they don't have a generally accepted name for it.
I have added the explanation after the other detailed explanations of
`count_values`, `topk` and `bottomk`. I think that fits quite nicely
into the flow.
Signed-off-by: beorn7 <beorn@grafana.com>
Update the aggregation operator documentation.
* Include before expression style syntax as valid.
* Update examples to show before style.
Signed-off-by: Ben Kochie <superq@gmail.com>
