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Hi all, is there a way I can specify a task to run only once within a flow? I have noticed some of my tasks run concurrently, this is an issue when I am writing to a table

Sure, this is what concurrency limits are for

you can set a limit of 1 to only allow one active flow run of a given flow

(or one active task run with a given tag)

and to ensure your tasks run sequentially, you can use SequentialTaskRunner in Prefect 2.0 and LocalExecutor in Prefect 1.0

Thank you Anna, is there documentation I could use to look this up? <https://prefect-community.slack.com/archives/CL09KU1K7/p1655119965466709?thread_ts=1655119693.324589&amp;cid=CL09KU1K7>

it depends - are you asking for *Prefect 2.0* or *Prefect 1.0?*

1.0 <https://docs.prefect.io/>
2.0 <https://orion-docs.prefect.io/>

and search for concurrency limits

also <https://discourse.prefect.io/tag/concurrency-limits>