Error on the reports with drill-through links on SSRS 2012 SP2 -- Invalid URI: The Uri string is too long

Question

Hi, We are migrating SSRS 2008 R2 reports to SSRS 2012 SP2. (PS. SSRS 2012 SP2 has been applied.) Everything went smooth expect some reports which were using reporting services. These reports have some drilin-through actions and was passing in a huge
xml parameter. I referred to some other posts in which there were also some similar issues like "The Uri string is too long."  but they're different. My reports can be opened and the error only occurred when accessing the drill-through actions.
As I know, Microsoft has provided the fix for the known issue "The Uri string is too long." in sp1 but it looks it can't cover this kind of situation since I have installed the SSRS SP 2. Is there any solution? In addition, there's no such
issue on SSRS 2008 R2.
Thanks,
onizga

Answer 1

Hi onizga,
According to your description that you are migrating SSRS 2008 R2 reports to SSRS 2012 SP2, after migration you got some error like “The Uri string is too long” which only occurred when accessing the drill-through actions, right?
Usually, the issue can be caused when you try to pass some parameters that cause the URL length to exceed 65,520 characters for a Microsoft SQL Server 2012 Reporting Services (SSRS 2012), you cannot render the report, and you may receive the following error
message:
The value of parameter 'param' is not valid. (rsInvalidParameter).Invalid URI: The Uri string is too long.
This is an known issue and already have the hotfix SQL Server 2012 Service Pack1 Cumulative Update 9 (CU9) as you know, you can try to reinstall this hotfix to fixed this issue:
http://support.microsoft.com/kb/2916827 .Any issue after applying the update, please post it on the following thread or you can submit an feedback:
http://connect.microsoft.com/SQLServer/feedback/details/788964/ssrs-2012-invalid-uri-the-uri-string-is-too-long 
Similar threads for your reference:
SSRS - The value of parameter 'param' is
not valid. ---> System.UriFormatException: Invalid URI: The Uri string is too long.
Microsoft.ReportingServices.Diagnostics.Utilities.InvalidParameterException:
The value of parameter 'pSetOfScopes' is not valid. ---> System.UriFormatException: Invalid URI: The Uri string is too long
If you still have any question, please feel free to ask
Regards
Vicky Liu
If you have any feedback on our support, please click here