Is it possible to search for the absence of an attribute?

[jcarres-mdsol]

Turns out we have some bad client implementations and we have server spans without http.status_code which makes them very useless.
We want to hunt down every installation of this but I can't figure a query that would match them. Is it possible with the current TraceQl to do this?

[mapno]

Hi @jcarres-mdsol. Unfortunately, it's not possible yet. Currently only { .a != nil} is supported.

A workaround to finding these spans could be using span-metrics, adding http.status_code to its dimensions and doing the query with PromQL, which does support it tempo_spanmetrics_total{http_status_code=""}

[jcarres-mdsol]

Clever workaround but precisely we want to hunt down these implementations because we are planning to change one of the already available dimension status from unset to either ok or error and want to cover all the services.

I think we will add a processor to the opentelemetry collector that will check http.status_code and decide how to set status.code.
I think in practice this is how we will find these implementations, we will be using metrics to check what's still unset and then search for some example spans of those services and see why the processor was not able to set it to a value.

Thanks though, I did not know that nil was a special value which could be used.