Hi,
I am working on a project with SQL Server 2008 R2 and Reporting Services. This is highly customized with custom data extension (for SSRS to interact with the app database), complex RDL that uses embedded VB code as well as interfaces with an external assembly. This is just some general background.
My question is this: Our application interfaces with reporting services to create linked reports programmatically. We use three method calls:
var rs = new ReportingService2005()
rs.CreateLinkedReport(name, TargetFolderName, SourceReportName, null);
rs.SetReportParameters(path, reportParams);
rs.CreateReportHistorySnapshotAsync(path);
The problem is that calling this code in a loop or under some polling interval (continuous loop) will cause the following types of exceptions in the SSRS log file where some of the reports fail randomly:
processing!ReportServer_0-1!2d04!09/17/2012-16:03:51:: e ERROR: An exception has occurred in data set 'Theme'. Details: System.NullReferenceException: Object reference not set to an instance of an object.
at Microsoft.ReportingServices.OnDemandProcessing.RuntimeDataSet.ConstructRecordRow()
at Microsoft.ReportingServices.OnDemandProcessing.RuntimeDataSet.ReadRow()
at Microsoft.ReportingServices.OnDemandProcessing.RuntimeDataSet.ProcessRows()
at Microsoft.ReportingServices.OnDemandProcessing.RuntimeDataSet.Process()
at Microsoft.ReportingServices.OnDemandProcessing.RuntimeDataSet.ProcessConcurrent(Object threadSet)
BY REPLACING THE OFFENDING METHOD CALL rs.CreateReportHistorySnapshotAsync(path); WITH rs.CreateReportHistorySnapshot(path, warningsArray); ALL THE REPORTS WILL COMPLETE SUCCESSFULLY. HOWEVER WE HAVE PERFORMANCE REQUIREMENTS OF 1500 OF THESE REPORTS GENERATED IN LESS THAN 15 MINUTES. THE SYNCHRONOUS CALL IS MUCH TOO SLOW. HOW CAN WE OVERCOME THIS ISSUE WITH THE ASYNC CALL OR IS THERE A WAY TO DO SYNC CALL IN PARALLEL?
I have tried many things so far and cannot get anything working. Why is calling CreateReportHistorySnapshotAsync in tight succession causing these random failures. Attaching to VS and debugging with all exceptions on shows nothing.