I tried to plot using histogram_quantile with Prometheus with sum on two labels, i.e.
histogram_quantile(0.9, sum(rate(grpc_request_duration_seconds_bucket{service="$service"}[$interval])) by (le, grpc_method))
The resulting plot was not the same as me manually making a separate plot for each individual value of grpc_method:
histogram_quantile(0.9, sum(rate(grpc_request_duration_seconds_bucket{service="$service",grpc_method="GetGridFile"}[$interval])) by (le, grpc_method))
and
histogram_quantile(0.9, sum(rate(grpc_request_duration_seconds_bucket{service="$service",grpc_method="PostAgvState"}[$interval])) by (le, grpc_method))
