One thing you can do to speed things up is to eliminate the `=~` in your query. Using regexp matching means it has to do a string search over every instance in your Prometheus for each metric. Using exact matching (`=`) will speed things up a lot. Although you won't be able to do multiple matching if you want that in your dashboard variables.
On Mon, Sep 18, 2023 at 7:58 AM David Leibovic <[email protected]> wrote: > Hi there, I'm trying to optimize a slow query of this form: > > (1 * avg_over_time(foo{instance=~"$i"}[$interval]) <= 10) or > (2 * avg_over_time(foo{instance=~"$i"}[$interval]) <= 20) or > (3 * avg_over_time(foo{instance=~"$i"}[$interval]) <= 30) or > (10 * avg_over_time(foo{instance=~"$i"}[$interval])) > > I suspect it's slow because of the many duplicate calls to > avg_over_time(foo{instance=~"$i"}[$interval]) > > Is there some way to only call the avg_over_time function once and re-use > the results subsequently? I'm using Prometheus in conjunction with Grafana, > in case it's relevant. > > The full query I'm trying to optimize is much more complicated, but I > figured the above would be enough to understand the problem. But in case > it's helpful, here is the full query I am trying to optimize (it's an Air > Quality Index computation): > > ((50 - 0) / (12 - 0) * > ((avg_over_time(ambient_pm25_env{instance=~"$room.*"}[$aqi_interval]) <= > 12) - 0) + 0) or > ((100 - 51) / (35.4 - 12.1) * > ((avg_over_time(ambient_pm25_env{instance=~"$room.*"}[$aqi_interval]) > 12 > and avg_over_time(ambient_pm25_env{instance=~"$room.*"}[$aqi_interval]) <= > 35.4) - 12.1) + 51) or > ((150 - 101) / (55.4 - 35.5) * > ((avg_over_time(ambient_pm25_env{instance=~"$room.*"}[$aqi_interval]) > > 35.4 and > avg_over_time(ambient_pm25_env{instance=~"$room.*"}[$aqi_interval]) <= > 55.4) - 35.5) + 101) or > ((200 - 151) / (150.4 - 55.5) * > ((avg_over_time(ambient_pm25_env{instance=~"$room.*"}[$aqi_interval]) > > 55.4 and > avg_over_time(ambient_pm25_env{instance=~"$room.*"}[$aqi_interval]) <= > 150.4) - 55.5) + 151) or > ((300 - 201) / (250.4 - 150.5) * > ((avg_over_time(ambient_pm25_env{instance=~"$room.*"}[$aqi_interval]) > > 150.4 and > avg_over_time(ambient_pm25_env{instance=~"$room.*"}[$aqi_interval]) <= > 250.4) - 150.5) + 201) or > ((400 - 301) / (350.4 - 250.5) * > ((avg_over_time(ambient_pm25_env{instance=~"$room.*"}[$aqi_interval]) > > 250.4 and > avg_over_time(ambient_pm25_env{instance=~"$room.*"}[$aqi_interval]) <= > 350.4) - 250.5) + 301) or > ((500 - 401) / (500.4 - 350.5) * > ((avg_over_time(ambient_pm25_env{instance=~"$room.*"}[$aqi_interval]) > > 350.4 and > avg_over_time(ambient_pm25_env{instance=~"$room.*"}[$aqi_interval]) <= > 500.4) - 350.5) + 401) or > clamp_max(avg_over_time(ambient_pm25_env{instance=~"$room.*"}[$aqi_interval]), > 600) > > Thanks for any help you can provide! > > -- > You received this message because you are subscribed to the Google Groups > "Prometheus Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/prometheus-users/664689b3-9f45-4b05-9438-4225e2dce773n%40googlegroups.com > <https://groups.google.com/d/msgid/prometheus-users/664689b3-9f45-4b05-9438-4225e2dce773n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Prometheus Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/prometheus-users/CABbyFmrPbE_fjixveYZ4%3D0s2GdKEEADout9odJsu%2Byq7kymyqw%40mail.gmail.com.
