We are updating an application to a new SQL 2012 platform (SSRS version shows as 2011.0110.5058.00 ((SQL11_PCU_Main).140514-1820 ) in the log). The application calls the /ReportServer/ReportExecution2005.asmx web service to generate reports.
For some of the reports, we do not always return all of the columns defined in the report dataset. In the SSRS ReportServerService log, we see the expected error message "There is no data for the field at position ##.;"
The problem is - on this new server, it looks like it is taking 30 seconds for SSRS to write each of these error messages to the log. Which means a report with 1 row of data, but 15 columns missing from the dataset, is taking over 7.5 minutes to generate.
As you can see in the log - each of the error messages is logged exactly 30 seconds apart (10:18:43, 10:19:13, 10:19:43, 10:20:13, etc.)
It seems like something has to be wrong with the error reporting / logging in SSRS. Does anyone know what I should be looking at?