Issue: Cannot Re-Create Work Pool — Prefect Says It Already Exists

[bonlv2000]

Bug summary

Hi,

I deleted a work pool, but when I try to create a new one with the same name, I get this error:

"A work pool with this name already exists."

The pool does not show up in the UI or in prefect work-pool ls, so it seems like it wasn't fully removed.

Is there any cache or backend state that Prefect keeps that I need to clear?
How can I force-delete a work pool?

Thanks!

EVD:

Version info

prefect version
/home/azureuser/.local/lib/python3.10/site-packages/pydantic/_internal/_generate_schema.py:2249: UnsupportedFieldAttributeWarning: The 'default' attribute with value 'UTC' was provided to the `Field()` function, which has no effect in the context it was used. 'default' is field-specific metadata, and can only be attached to a model field using `Annotated` metadata or by assignment. This may have happened because an `Annotated` type alias using the `type` statement was used, or if the `Field()` function was attached to a single member of a union type.
  warnings.warn(
Version:              3.4.22
API version:          0.8.4
Python version:       3.10.12
Git commit:           6a6d114f
Built:                Fri, Oct 03, 2025 06:15 PM
OS/Arch:              linux/x86_64
Profile:              default
Server type:          server
Pydantic version:     2.12.5
Server:
  Database:           sqlite
  SQLite version:     3.37.2

Additional context

No response

[desertaxle]

Thanks for the issue @bonlv2000! Are you able to create a work pool with that name from the CLI? Just trying to narrow down where the error is originating from. If you could also share the API response from the work pool create call by inspecting the network calls in the browser developer tool, that would be helpful.

[bonlv2000]

Thanks for the issue @bonlv2000! Are you able to create a work pool with that name from the CLI? Just trying to narrow down where the error is originating from. If you could also share the API response from the work pool create call by inspecting the network calls in the browser developer tool, that would be helpful.

Hi @desertaxle , I tried creating the work pool again using the CLI, but it still shows the same error even though there are no existing work pools with that name.

=>

root@test-worker-a-69bfd55574-5784b:/app# prefect work-pool create a-worker-pool --type azure-container-instance
WARNING: Active profile 'default' set by environment variable not found. The default profile will be used instead.
Work pool named 'a-worker-pool' already exists. Please use --overwrite to update it.

root@test-worker-a-69bfd55574-5784b:/app# prefect work-pool create a-worker-pool --type azure-container-instance --overwrite
WARNING: Active profile 'default' set by environment variable not found. The default profile will be used instead.
Traceback (most recent call last):
File "/usr/local/lib/python3.13/site-packages/prefect/client/orchestration/_work_pools/client.py", line 424, in read_work_pool
response = await self.request(
^^^^^^^^^^^^^^^^^^^
...<3 lines>...
)
^
File "/usr/local/lib/python3.13/site-packages/prefect/client/orchestration/base.py", line 53, in request
return await self._client.send(request)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.13/site-packages/prefect/client/base.py", line 411, in send
response.raise_for_status()
~~~~~~~~~~~~~~~~~~~~~~~~~^^
File "/usr/local/lib/python3.13/site-packages/prefect/client/base.py", line 165, in raise_for_status
raise PrefectHTTPStatusError.from_httpx_error(exc) from exc.cause
prefect.exceptions.PrefectHTTPStatusError: Client error '404 Not Found' for url 'https://test-prefect.platform.com/api/work_pools/a-worker-pool'
Response: {'detail': 'Work pool "a-worker-pool" not found.'}
For more information check: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/404

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "/usr/local/lib/python3.13/site-packages/prefect/cli/_utilities.py", line 44, in wrapper
return fn(*args, **kwargs)
File "/usr/local/lib/python3.13/site-packages/prefect/cli/_types.py", line 156, in sync_fn
return asyncio.run(async_fn(*args, **kwargs))
~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.13/asyncio/runners.py", line 195, in run
return runner.run(main)
~~~~~~~~~~^^^^^^
File "/usr/local/lib/python3.13/asyncio/runners.py", line 118, in run
return self._loop.run_until_complete(task)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
File "/usr/local/lib/python3.13/asyncio/base_events.py", line 725, in run_until_complete
return future.result()
~~~~~~~~~~~~~^^
File "/usr/local/lib/python3.13/site-packages/prefect/cli/work_pool.py", line 328, in create
work_pool = await client.create_work_pool(work_pool=wp, overwrite=overwrite)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.13/site-packages/prefect/client/orchestration/_work_pools/client.py", line 491, in create_work_pool
existing_work_pool = await self.read_work_pool(
^^^^^^^^^^^^^^^^^^^^^^^^^^
work_pool_name=work_pool.name
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
)
^
File "/usr/local/lib/python3.13/site-packages/prefect/client/orchestration/_work_pools/client.py", line 432, in read_work_pool
raise ObjectNotFound(http_exc=e) from e
prefect.exceptions.ObjectNotFound: None
An exception occurred.

root@test-worker-a-69bfd55574-5784b:/app# prefect work-pool ls
WARNING: Active profile 'default' set by environment variable not found. The default profile will be used instead.
Work Pools
┏━━━━━━┳━━━━━━┳━━━━┳━━━━━━━━━━━━━━━━━━━┓
┃ Name ┃ Type ┃ ID ┃ Concurrency Limit ┃
┡━━━━━━╇━━━━━━╇━━━━╇━━━━━━━━━━━━━━━━━━━┩
└──────┴──────┴────┴───────────────────┘
(**) denotes a paused pool
root@test-worker-a-69bfd55574-5784b:/app#

[desertaxle]

Hmmm, that's odd. Can you check your DB and see if there's any data in the work pools table?

[bonlv2000]

Hmmm, that's odd. Can you check your DB and see if there's any data in the work pools table?

I’m storing Prefect in PostgreSQL, and when I check the tables there are no rows, but it still gives the error “A work pool with this name already exists.” Is Prefect saving some kind of cache somewhere?

[bdalpe]

@bonlv2000 can you give us some more context on the infrastructure being used to run Prefect and how you set everything up?

[bdalpe]

I see this in the prefect version output...

Server:
  Database:           sqlite
  SQLite version:     3.37.2

Something is not configured correctly if you're telling us that PostgreSQL is being used.

[bonlv2000]

I see this in the prefect version output...

Server:
  Database:           sqlite
  SQLite version:     3.37.2

Something is not configured correctly if you're telling us that PostgreSQL is being used.

Thank you for your response. I have now switched to the PostgreSQL type, but I still cannot initialize it successfully. I’m not sure what is causing this issue.

[bonlv2000]

I see this in the prefect version output...

Server:
  Database:           sqlite
  SQLite version:     3.37.2

Something is not configured correctly if you're telling us that PostgreSQL is being used.

I am still encountering this error.

root@test--prefect-79b75c8c6c-w89h8:/opt/prefect# prefect version /usr/local/lib/python3.13/site-packages/pydantic/_internal/_generate_schema.py:2249: UnsupportedFieldAttributeWarning: The 'default' attribute with value 'UTC' was provided to the Field()function, which has no effect in the context it was used. 'default' is field-specific metadata, and can only be attached to a model field usingAnnotatedmetadata or by assignment. This may have happened because anAnnotatedtype alias using thetypestatement was used, or if theField()` function was attached to a single member of a union type.
warnings.warn(
Version: 3.4.22
API version: 0.8.4
Python version: 3.13.9
Git commit: 3f530458
Built: Fri, Nov 07, 2025 06:40 AM
OS/Arch: linux/x86_64
Profile: ephemeral
Server type: server
Pydantic version: 2.12.4
Server:
Database: postgresql
PostgreSQL version: 16.10
Integrations:
prefect-redis: 0.2.5
root@test--prefect-79b75c8c6c-w89h8:/opt/prefect# prefect work-pool ls
Work Pools
┏━━━━━━┳━━━━━━┳━━━━┳━━━━━━━━━━━━━━━━━━━┓
┃ Name ┃ Type ┃ ID ┃ Concurrency Limit ┃
┡━━━━━━╇━━━━━━╇━━━━╇━━━━━━━━━━━━━━━━━━━┩
└──────┴──────┴────┴───────────────────┘
(**) denotes a paused pool
root@test--prefect-79b75c8c6c-w89h8:/opt/prefect# prefect work-pool create a-worker-pool --type process
Work pool named 'a-worker-pool' already exists. Please use --overwrite to update it.
root@test--prefect-79b75c8c6c-w89h8:/opt/prefect# prefect work-pool create a-worker-pool --type process --overwrite
Traceback (most recent call last):
File "/usr/local/lib/python3.13/site-packages/prefect/client/orchestration/_work_pools/client.py", line 424, in read_work_pool
response = await self.request(
^^^^^^^^^^^^^^^^^^^
...<3 lines>...
)
^
File "/usr/local/lib/python3.13/site-packages/prefect/client/orchestration/base.py", line 53, in request
return await self._client.send(request)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.13/site-packages/prefect/client/base.py", line 411, in send
response.raise_for_status()
~~~~~~~~~~~~~~~~~~~~~~~~~^^
File "/usr/local/lib/python3.13/site-packages/prefect/client/base.py", line 165, in raise_for_status
raise PrefectHTTPStatusError.from_httpx_error(exc) from exc.cause
prefect.exceptions.PrefectHTTPStatusError: Client error '404 Not Found' for url 'https://test--prefect.-platform.com/api/work_pools/a-worker-pool'
Response: {'detail': 'Work pool "a-worker-pool" not found.'}
For more information check: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/404

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "/usr/local/lib/python3.13/site-packages/prefect/cli/_utilities.py", line 44, in wrapper
return fn(*args, **kwargs)
File "/usr/local/lib/python3.13/site-packages/prefect/cli/_types.py", line 156, in sync_fn
return asyncio.run(async_fn(*args, **kwargs))
~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.13/asyncio/runners.py", line 195, in run
return runner.run(main)
~~~~~~~~~~^^^^^^
File "/usr/local/lib/python3.13/asyncio/runners.py", line 118, in run
return self._loop.run_until_complete(task)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
File "/usr/local/lib/python3.13/asyncio/base_events.py", line 725, in run_until_complete
return future.result()
~~~~~~~~~~~~~^^
File "/usr/local/lib/python3.13/site-packages/prefect/cli/work_pool.py", line 328, in create
work_pool = await client.create_work_pool(work_pool=wp, overwrite=overwrite)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.13/site-packages/prefect/client/orchestration/_work_pools/client.py", line 491, in create_work_pool
existing_work_pool = await self.read_work_pool(
^^^^^^^^^^^^^^^^^^^^^^^^^^
work_pool_name=work_pool.name
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
)
^
File "/usr/local/lib/python3.13/site-packages/prefect/client/orchestration/_work_pools/client.py", line 432, in read_work_pool
raise ObjectNotFound(http_exc=e) from e
prefect.exceptions.ObjectNotFound: None
An exception occurred.`

[bonlv2000]

I’ve resolved the issue, although I’m not entirely sure what caused it.
Since this is a development environment, I removed everything related to Prefect and reinstalled it (pip uninstall prefect, then reinstall).
After doing that, the system started working normally again.