There are a few configuration values can be changed to improve long running reports.
SQLServer 2014: \Program Files\Microsoft SQL Server\MSRS12.mssqlSERVER\Reporting Services\ReportServer\rsreportserver.config
Updated to:
― https://www.mssqltips.com/sqlservertip/2197/how-to-speed-up-ms-sql-server-reporting-services-ssrs-on-first-run/
https://msdn.microsoft.com/en-us/library/ms157273(v=sql.120) .aspx
Check Trace log file :
The trace log files are ReportServerService_.log and are located in the following folder:
C:\Program Files\Microsoft SQL Server\MSRS12.MSSQLSERVER\Reporting Services\LogFiles
Read log information from ExecutionLog3 view
T-SQL
Use ReportServer
select * from ExecutionLog3
Order by TimeStart DESC
https://msdn.microsoft.com/en-us/library/ms159110(v=sql.120) .aspx