JSON Serialization String Length Error

[rbowen]

All - 

I'm experiencing an error in the PowerBI Service when a particular report attempts to do its regular scheduled refresh. The error message is:

"M Engine error: 'System.Web.Extensions; Error during serialization or deserialization using the JSON JavaScriptSerializer. The length of the string exceeds the value set on the maxJsonLength property. Parameter name: input'. The current operation was cancelled because another operation in the transaction failed. Table: Sales."

Apparently, there's some issue with the Sales table in the BI report. However, in BI Desktop, the entire report can be refreshed manually without any issues, including the Sales table. Is there a way to increase the string length for the maxJsonLength property, or something that can be tweaked in the BI Desktop file?

[nilendraFabric]

Hello @rbowen 

Power BI Desktop uses a local engine and does not enforce the same JSON serialization limits as the Power BI Service.

you cannot directly configure or increase the `maxJsonLength` property in the Power BI Service. This property can be set in a web.config file for custom ASP.NET applications, but Power BI Service is a managed, multi-tenant environment where such configuration is not exposed to end users

• Power BI Service runs in a cloud environment, and the backend may use ASP.NET components with strict serialization limits for security and performance reasons. These limits are not user-configurable from the Power BI Desktop file (.pbix)

[rbowen]

Hi Nilendra, and thank you. This report absolutely must do daily scheduled refreshes so how do I get around this issue?

[lbendlin]

run separate, smaller queries that keep the payload under the 32K limit.

[rbowen]

@lbendlin  and @nilendraFabric  - 

Breaking up the queries wasn't an option for this report, however, I was able to do some other tweakin in the Desktop file that resolved the issue. Thank you both very much for the information. Very helpful and actually gave me some ideas to try that ultimately fixed the issue. 

Cheers.

[MSISTHEWORST]

Hello @rbowen,

I kind of run into the same issue and my long query is the solution to antoher problem I had :D. Could you share your fix, maybe it will help me too :(.

[v-bmanikante]

Hello @rbowen Thank you for reaching out Microsoft Fabric Community Forum.

@nilendraFabric @lbendlin Thank you for your responses.

@rbowen 

It looks like your problem has been solved, please mark the helpful reply and accept it as solution, it will be helpful for other members of the community who have similar problems as yours to solve it faster .

Thank you very much for your kind cooperation!

Regards,

B Manikanteswara Reddy

[v-bmanikante · Accepted solution]

Hello @rbowen Thank you for reaching out Microsoft Fabric Community Forum

As we haven’t heard back from you, we wanted to kindly follow up to check if the solution provided for the issue worked? or Let us know if you need any further assistance?

If our response addressed, please mark it as Accept as solution and click Yes if you found it helpful.

Regards,

B Manikanteswara Reddy