ADFv2 Queue time

Question

I have a pipeline with a few copy activities. Some of those activities are in charge of copying large amounts of data from a storage account to the same storage account but in a compressed manner (I'm talking about a few TB of data).

After running the pipeline for a few hours I noticed that some activities show "Queue" time on the monitoring blade and I was wondering what can be the reason for that "Queue" time. And more importantly if I'm being billed for that time also because from what I understand my ADF is not doing anything.

Can someone shed some light? :)

Answer 1

(Posting this as an answer because of the comment chars limit)

After a long discussion with Azure Support and reaching out to someone at the ADF product team I got some answers:

1 - The queue time is not being billed.

2 - Initially, the orchestration ADF system puts the job in a queue and it gets "queue time" until the infrastructure picks it up and start the processing part.

3 - In my case the queue time was increasing after the job started because of a bug in the underlying backend executor (it uses Azure Batch). Apparently the executors were crashing and my job was suffering from "re-pickup" time, thus increasing the queue time. This explained why after some time I started to see that the execution time and the transferred data were decreasing. The ETA for this bugfix is at the end of the month. Additionally the job that I was executing timed out (after 7 days) and after checking the billing I confirmed that I wasn't charged a dime for it.