topic Re: Difference DQL Calculate diference of two timeseries metrics in DQL

Difference DQL Calculate diference of two timeseries metrics

robert_laurat — Fri, 27 Mar 2026 10:45:26 GMT

Hi everyone,

I want to create a difference between two metrics over the time. For example to show the differnece between published and processed queue messages.
How to do this with DQL?

I tried to start with this command.

timeseries {publish_count = sum(dt.service.messaging.publish.count), receive_count = sum(dt.service.messaging.receive.count)}, by:{messaging.destination.name} | fieldsAdd difference = publish_count - receive_count | summarize by:{messaging.destination.name}, total_difference = sum(difference)

But this just return null.

Best regards,

Robert

Re: Difference DQL Calculate diference of two timeseries metrics

MaximilianoML — Thu, 26 Mar 2026 17:21:14 GMT

Hello @robert_laurat,

timeseries returns arrays, so publish_count and receive_count are not single values.
Also, empty buckets are null unless you set default: 0.

Try this for the difference over time:

timeseries { publish_count = sum(dt.service.messaging.publish.count, default: 0), receive_count = sum(dt.service.messaging.receive.count, default: 0) }, by: { messaging.destination.name } | fieldsAdd difference = publish_count[] - receive_count[]

That gives you a difference array for each destination, one value per time bucket. Dynatrace supports iterative array expressions like this with [].

I hope this helps you 😀

Re: Difference DQL Calculate diference of two timeseries metrics

robert_laurat — Fri, 27 Mar 2026 07:04:19 GMT

Hi @MaximilianoML, the default:0 was the trick.

I also tried to explicitly set [] at the calculation, but without success.

Thanks,

Robert