@Marvin I'm getting this error:

Failed("Flow run encountered an exception. PrefectHTTPStatusError: Client error '429 Too Many Requests'"

What is the limit? How can I solve this?

It appears that you've hit the Prefect API rate limits. Prefect Cloud has the following rate limits: - 400 flow and task runs per minute for personal accounts - 2,000 flow and task runs per minute for organization accounts When these limits are triggered, the Prefect Cloud API will return a 429 response with an appropriate Retry-After header source. To address this issue, you can try the following: 1. Reduce the number of logs to avoid overloading the database. 2. Set concurrency limits on some tasks. You can find more information on this Discourse thread. Remember, with great power comes great responsibility... to manage API rate limits.

Thanks! @Marvin How do I Set concurrency limits on some tasks?

Setting concurrency limits on tasks in Prefect can be done using the

max_concurrent

parameter of the

Semaphore

class. A semaphore is a synchronization primitive that can be used to limit the number of concurrent tasks running at the same time. Here's an example of how to use a semaphore to limit concurrency:

python
from prefect import Flow, task
from prefect.executors import LocalExecutor
from prefect.schedules import IntervalSchedule
from prefect.triggers import any_successful
from prefect.utilities.tasks import Semaphore

# Create a semaphore with a concurrency limit of 2
semaphore = Semaphore(max_concurrent=2)

@task
def task_a():
    print("Task A")

@task
def task_b():
    print("Task B")

@task
def task_c():
    print("Task C")

with Flow("concurrency_example") as flow:
    a = task_a()
    b = task_b()
    c = task_c()

    # Acquire the semaphore before running the tasks
    semaphore.acquire(a)
    semaphore.acquire(b)
    semaphore.acquire(c)

    # Release the semaphore after the tasks are completed
    semaphore.release(a)
    semaphore.release(b)
    semaphore.release(c)

# Run the flow
flow.run(executor=LocalExecutor())

In this example, the

Semaphore

class is used to limit the concurrency of tasks A, B, and C to a maximum of 2 concurrent tasks. The tasks will acquire the semaphore before running and release it after completion. Remember, it's not the size of your semaphore that matters; it's how you use it.

Thanks but @Marvin can you provide how to set concurrency limits for Prefect 2?

Edited by @Nate: Apologies for the confusion. Here's an example using the CLI:

prefect concurrency-limit [command] [arguments]

details here (https://docs.prefect.io/latest/concepts/tasks/?h=concu#cli) you can check out the work queue level concurrency rate limit docs (https://docs.prefect.io/latest/concepts/work-pools/?h=concurrency#work-pool-concurrency) or task-level concurrency here (https://docs.prefect.io/latest/concepts/tasks/?h=concurr#task-run-concurrency-limits)

ive edited marvins answer here, still working on marvin’s focus on prefect 2 (lots of prefect 1 content on the internet pre sept 2021) probably should have produced a better answer here even so 👀

@Sean Conroy a product advocate will DM for support. Thanks for reaching out.