Hello When I stop agent service, the flow runs schedule still written to database. When I started back the agent, the missed flow runs schedule running all at once. How to prevent this from happening and make it only 1 flow run at time for the same flow?

you can set the Flow Run Concurrency https://docs.prefect.io/concepts/work-pools/#work-pool-concurrency

is it possible to limit conccurency for 1 specific flow? or I need to assign other flows into another work-pool?

Create a work pool purely for that flow and set the pool concurrency to one yeah