we get the following error when running a query to our Synapse SQL Serverless database:
Error handling external file: 'WaitIOCompletion call failed. HRESULT = 0x8007000C'. File/External table name: '<redacted: path to file on storage account>'.
This error occurs when querying a view which uses OPENROWSET, e.g.:
SELECT * FROM OPENROWSET( BULK 'PATH/ON/STORAGE/ACCOUNT/**', DATA_SOURCE = 'AzureDataLakeStoreV2', FORMAT = 'PARQUET' ) t
The folder in the storage account contains several parquet files in subfolders, all files with the same structure.
Managed identify authentication is used for the data source.
I am not able to find any information about when 'WaitIOCompletion call failed' can occur.
Following discovering have been made:
- When recreating the view the query runs fine afterwards
- Still, after updating data in the storage account, the error occurs again
- Other views/queries work just fine
- We have different identical environments on which the problem does not occur (obviously there has to be a difference somewhere, still Synapse environments are configured in the same manner)
- When running this query outside of Synapse Studio with a user authenticated by AD Authentication the query also works fine -> seems like there is something going on with the managed identity authentication
- Recreating external data source and scoped credential did not solve the problem.
- Recreating the folder structure in the storage account was also of no prevail
I can provide more information about our setup if required.
Thanks for your help.