The parameter screen and subscription screen load very slow when there are parameter lists with more than 2000 records. Loading time more than 10 minutes.
This issue doesn't occur when opening the report.
It looks like the issue happens to RDL report on Power BI report server, right? Besides update PBIRS version, is there any other changes made to the RDL or data sources recently?
Are these 2000 records for the parameter necessarily? If not, please remove unused values. Otherwise, please try to create a cascading parameter to decrease parameter list each time.
After you run the report in Power BI report server, please go to report server database, check [ExecutionLog2] view to see how many time spent in TimeDataRetrieval.
Please update to the most new PBIRS version which released on 8/28/2018 then test again.
Best Regards,Qiuyun Yu