Hi I have a question about concurrency I have a queue with c

Question

Hi I have a question about concurrency I have a queue with concurrency = 1 Yesterday I manually started a job run via UI and also I have scheduled the same flow to run in 10 hours or so The manually triggered job didn t finished in 10 hours so another one shouldn t have started because concurrency = 1 but it did start Am I doing something wrong

Christopher Boyd · Answer

Is this Prefect 1 or Prefect 2 Are you using tags How is your concurrency configured

Igor Kotua · Answer

Prefect Cloud Concurrency configured on a queue level I have a queue dedicated only for 1 flow For this queue I set concurrency = 1

Igor Kotua · Answer

Also I added tag limiting concurrency to 1 for each task inside this flow also didn t help

Christopher Boyd · Answer

prefect cloud is the cloud offering not necessarily 1 or 2

Christopher Boyd · Answer

there is prefect cloud 1 and prefect cloud 2

Igor Kotua · Answer

prefect cloud 2

Christopher Boyd · Answer

Did you submit the run manually with tags What about the scheduled one The concurrency limit should be set on matching flows and runs where matching is decided based on the tags submitted to the agent

Igor Kotua · Answer

Tags are written in code so I guess they are always there

Christopher Boyd · Answer

when you look at the flow run history are you able to see the tags in the logs when the flow is submitted

Christopher Boyd · Answer

I m trying to determine when you submit a manual run versus a scheduled run if the tagset matched which is what the concurrency limit should be keying off of

Christopher Boyd · Answer

if they were submitted ot the same agent

Igor Kotua · Answer

Hmm but when I set concurrency 1 limit on a whole queue and all runs are inside this queue should I also match tags

Christopher Boyd · Answer

yes

Christopher Boyd · Answer

<https docs prefect io concepts work queues work queue concurrency> ```For example a work queue with a concurrency limit of 5 will only release new work if fewer than 5 matching runs are currently in a Running or Pending state If 3 runs are Running or Pending polling the queue for work will only result in 2 new runs even if there are many more available to ensure that the concurrency limit is not exceeded ```

Christopher Boyd · Answer

The matching runs are based on tags not necessarily the queue itself

Igor Kotua · Answer

I don t understand sorry

Igor Kotua · Answer

I have a queue concurrency limit of 1 one task have been running second task still started it was autoscheduled

Igor Kotua · Answer

By task I mean flow here couldn t set tags on flows as far as I see

Igor Kotua · Answer

Here is a picture

Igor Kotua · Answer

Liberal grebe was started manually at 6 55 p yesterday

Igor Kotua · Answer

It was running 17 hours before failing so up until 12 am today Teal calm started at 5 am today while another flow has been running

Igor Kotua · Answer

And as you see flow run concurrency is 1 on the picture

Igor Kotua · Answer

Previously flow run concurrency was working fine for me

Igor Kotua · Answer

May be the problem is because this run was manually triggered

Igor Kotua · Answer

Sorry for so much text really appreciate your time looking into this

Christopher Boyd · Answer

When you click into the flow run for each what are the tags assigned e g

Igor Kotua · Answer

One has a tag autoscheduled

Igor Kotua · Answer

Another has no tags

Christopher Boyd · Answer

That would be the discrepancy

Christopher Boyd · Answer

The concurrency is matching tags

Christopher Boyd · Answer

if the tags don t match concurrency is not enforced as it s unaware that it needs to be enforced

Igor Kotua · Answer

Thanks

Igor Kotua · Answer

But to be honest it s a bit strange behaviour