<@ULVA73B9P> how can i limit the number of concurr...
# ask-marvin
g
@Marvin how can i limit the number of concurrent mapped tasks running
m
To limit the number of concurrent mapped tasks running in Prefect, you can use task concurrency limits via task tags. Here are the main points: 1. Task Concurrency Limits: Prefect allows you to set concurrency limits that apply to tasks with a specific tag. This is useful for scenarios where a resource (like a database) can only handle a limited number of concurrent connections. 2. Global Concurrency Limits: You can also manage concurrency using a global concurrency limit (GCL), which can be created and managed using Prefect's CLI. Example of setting a task concurrency limit:
Copy code
python
from prefect import task, flow

@task(tags=["database_task"])
def my_task(x):
    return x

@flow
def my_flow():
    my_list = list(range(1000))
    results = my_task.map(my_list)
    return results

if __name__ == "__main__":
    # Set the task concurrency limit for 'database_task' tag
    import prefect
    prefect.context.concurrency_limits = {"database_task": 10}
    my_flow()
Example of using Global Concurrency Limits:
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bash
# Create a global concurrency limit
prefect gcl create my-concurrency-limit --limit 10

# Use the concurrency limit in a Prefect flow
from prefect import concurrency

@flow
def my_flow():
    with concurrency("my-concurrency-limit"):
        my_list = list(range(1000))
        results = my_task.map(my_list)
    return results
For more detailed information, check out the Prefect documentation: Task Concurrency Limits Global Concurrency Limits Additionally, you can monitor relevant issues and discussions on GitHub regarding task concurrency and mapping improvements: GitHub Issues on Limiting Concurrent Mapped Tasks Hope this clears up how to manage concurrency limits in Prefect!