Max of multiple math expressions in Grafana Alert

Grafana Alerting
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1

Grafana v10.4.7 (8d068faebe), I can not update this version, its managed.

I have a Grafana Alert with multiple math expressions G and K that give integer values in vector form:

G:
{namespace="first"} => 0
{namespace="second"} => 2
{namespace="third"} => 0
{namespace="fourth"} => 4

K:
{namespace="first"} => 6
{namespace="second"} => 1
{namespace="third"} => 0
{namespace="fourth"} => 2

How do I get the maximum of these two expression results, so that the math expression result would be:

{namespace="first"} => 6
{namespace="second"} => 2
{namespace="third"} => 0
{namespace="fourth"} => 4

Of course I want a solution where i can use more expression results, in my case I need the maximum of 7 other math expressions…

max($G, $K) gives error, not to mention that it is not supported AFAIK.

I have checked all other expression options, non seems todo what I want:

Screenshot from 2025-04-30 12-08-05
Screenshot from 2025-04-30 12-08-05186Ă—258 6.92 KB

Is this possible? If so how?

2

You’re right — Grafana’s expression engine currently does not support max() across multiple vector expressions directly like you would in Prometheus. The math expression (like $G > $K ? $G : $K) only supportsvscalar or element-wise math but not aggregation across multiple expressions directly.
Step-by-step workaround for max across multiple expressions:
Let’s say you have expressions:

  • A, B, C, D, E, F, G

Step 1: Pairwise max expressions Start creating math expressions like this:

  • X1 = $A > $B ? $A : $B
  • X2 = $C > $D ? $C : $D
  • X3 = $E > $F ? $E : $F

Step 2: Combine again

  • X4 = $X1 > $X2 ? $X1 : $X2
  • X5 = $X3 > $G ? $X3 : $G

Step 3: Final max

  • XFinal = $X4 > $X5 ? $X4 : $X5
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