equivalent to "abs(ideriv(quantile())" from VictoriaMetrics

[Denny Fuchs]

Hello,

I'm new to Prometheus and trying out Thanos. I'm coming from the InfluxDB / Telegraf world and I found a Template for Grafana, which is a fork, we use for InfluxDB.  It is for Victoriametrics and uses in the Grafana template some functions, PromQL does not have.

One of them is: abs(ideriv)): On the side from VictoriaMetrics() it means: "ideriv(m) - for calculating instant derivative for m."

I have something like:

abs(ideriv(quantile(0.5,net_bytes_recv{host =~ "$server",interface =~ "(vlan|eth|bond|ens).*"}) by (host,interface)))*8

Is there a way to get the same, so that I can search/replace this function ?

cu denny

[Ben Kochie]

That's a very weird query to be sure.

I guess it depends a lot on what net_bytes_recv is. Is the underlying data a gauge of bytes per second? Or is it a counter? 

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[Denny Fuchs]

Hi,

in that case, its a gauge ...

https://github.com/influxdata/telegraf/blob/master/plugins/inputs/net/NET_README.md

and its also used for many other graphs too, like disk :-)

cu denny

[Brian Brazil]

>in that case, its a gauge ...

That's a counter, node_network_receive_bytes_total is the equivalent in the node exporter. I take it the expression is meant to be calculating instantaneous bits received per second?

In PromQL that would be irate(net_bytes_recv{host=~"$server",interface=~"(vlan|eth|bond|ens).*"}[1m])*8

I think the quantile is a noop, and if it wasn't it'd have been preventing you from having any useful metrics as rate always needs to be first and you can't do math on quantiles. Deriv is also not safe to use with counters, it's only for gauges.

PromQL would have given you an error for this form of query, as it doesn't make sense.

> and its also used for many other graphs too, like disk :-)

You might want to look for a different dashboard to work from, that expression is not calculating bits received per second or anything else meaningful.

Brian

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Brian Brazil

www.robustperception.io

[Denny Fuchs]

Hello Brian,

thanks a lot. I've found a new dashboard, also for Telegraf with the same overall state :-)

cu denny