Calculate error rate from two rows based on dimension

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  • What are you trying to achieve?
    Hi there, I am trying to make a status history graph showing the error / success situation of the system. Ideally with an error rate (error / (error + success)).

  • How are you trying to achieve it?
    I did a search to AWS cloudwatch, which contains two different MetricNames (Error and Success) and used regex to show different colors of errors and success.

  • What happened?

    Screenshot 2024-05-07 at 11.36.57
    Screenshot 2024-05-07 at 11.36.571740Ă—958 27.1 KB

    I would like to combine the two metrics of each dimension (e.g. B - failed and B - success) into one row based on math expressions. I tried expression, but I couldn’t specify which rows will be combined. With binary operation under “Add field from calculation” it is only possible to do basic ±*/ , but I want something like error / (success + error).

Any suggestions?

2

you can do two binary operation steps,

success + error = total

then

error / total

then error * 100 if you want percent

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3

Thanks for the reply. I thought of that as well. Surely it’s a good workaround. But ideally I would like to have something that make the calculation using the rows with the same label instead of manually choosing the two rows in a binary calculation, because the incoming data can be versatile.

1 Like
4

IMHO you can use CloudWatch math in this case:

You can use CloudWatch math also in the Grafana.

1 Like
5

Thanks for the suggestion. As mentioned, I tried the calculation in expression already, but I couldn’t specify which rows will be combined. So if I use $a + $b, then all rows returned from $a will be added to all rows returned from $b.

6

CloudWatch math != Grafana expression.

7

Could you elaborate a bit more, please? I thought the math in expression is the way to do something like cloudwatch math in Grafana environment. Or do you mean doing cloudwatch math in AWS in advance?

8

Cloudwatch math in AWS => you can use cloudwatch math also in Grafana (but that’s not a Grafana expression). Search on the forum and you will find example how. E.g.