CPU consumption - Postgres

Hello. I currently have a deployment in k8s via de Temporal Helm repository with 1.8.0 version.
For persistence I use a managed Postgres from Azure. This is a MVP project.

I have two environments with isolated resources.

In preprod I have 2Vcpu and in prod 4Vcpu.

The temporal runs a distributed cron job at 10 minutes interval, whose logic is implemented by a backend.

Due to the fact I noticed some high cpu consumption in preprod I stopped the backend process, leaving in preprod running only temporal.

At some point I started having almost contant >90% cpu consumption on preprod, while in prod I have constant ~10%.

After I restarted all pods from temporal seems CPU for now went down to around ~10 percent in preprod as well, or anyway very low comparing to the constant spike I had.

Postgres is version 11 in Azure.
And also data retention for namespace in 7 days.

Now my question is, what could have caused the high CPU, since even when only the temporal was running with a cron job activated, I still had same CPU, after stopping the backend.

For the cron job workflow I also have some retries set and timeouts on client side, but anyway the backend was stopped.

Do you have any insight I can look into. I know there were little resources in the envs, but it’s an MVP project, and what worried me is the difference between prod and preprod.

I also want to mention that the high CPU started only after a very good number of days of continous run. So it might have so relevance to the issue.

can you provide the metrics below?

plz also include the operation information, e.g.
not sum(persistence_requests)
but sum(persistence_requests) by (operation)