Refresh Error

[markroberts]

I am recieving the following error when running a refresh using the Personal Gateway for some datasets:

The value of prefixLength argument must be 1,2, or 4.
Parameter name: prefixLength

This usually (but not always) occurs through scheduled refresh. The datasets are usually (but not always) the same 2 (of about 7) each time. It sometimes (but not always) occurs when doing a manual refresh.

Could anyone advise a solution.

[santoshrnath]

This Error will have if any data type is changed in the database. You need to make the changes in the Query, Apply it to the model and then re-upload to resolve the issue.

[Jasper]

Hi Mark,

I have the same problem. Do you know what caused the error?

Thanks! Jasper

[Anonymous]

Hi @markroberts，

What’s involved in the two datasets? Based on my research, the above error message could occur when there are complicated SQL queries such as view or unsupported data types in the data source, you can review this similar blog for your reference.

In your scenario, I would recommend you check if there is exception with elements definition in the two datasets. And as mentioned in the above blog, when refreshing data in Power BI, it is better to use standardized types and cleanse your data as close to the source as possible.


Thanks,
Lydia Zhang

[markroberts]

Please note that I am not a programmer so my understanding of the response to my question is limited. Since the strength of Power BI is to allow analysis of data by non-IT specialists, I would like to think that answers to questions would not require specialist IT staff to understand them. Please advise if this is possible.

The data refreshes continue to fail for some of my datasets some of the time, some of them most of the time. The data is extracted from a MySQL database.

The full message text is as follows:

Processing error:	The value of prefixLength argument must be 1,2, or 4. Parameter name: prefixLength
Cluster URI:	WABI-AUSTRALIA-SOUTHEAST-redirect.analysis.windows.net
Activity ID:	7469f155-6579-4760-9f94-8225c7b810ff
Request ID:	645052b8-fe7f-41b8-84d8-de7ddb750ad1
Time:	2016-08-21 18:33:55Z

[billmanh]

I've noticed this error when connecting  to an Azure cube (as you are). When I downloaded the PBIX file I saw that the credentials were bad (which returned a table with a single row with text for error rather than an actual 404/403 error). I  refreshed the credentials and republished and the problem was solved. This could mean that the credential error is not registering in the service. Just a thought 🙂