title: Subreport Performance Difference Between SSRS and BIDS
body: <p>I've got a report in SSRS that contains two subreports, but it's taking a very long time to show the final report. According to the SSRS Execution Log, the report is spending ~140ms in data retrieval, ~20minutes in processing, and ~20ms in rendering. If I remove either of the subreports (doesn't matter which one), the time drops to ~10minutes for processing. If I remove both subreports, the time drops to ~2s. Quite obviously I have to do something about the subreports; probably try to integrate them into the main report.</p>
  
  <p>Does the "TimeDataRetrieval" statistic in the execution log represent the aggregate data retrieval time for the report and all subreports, or is it just for the main report (meaning the data retrieval times for subreports are actually being added to the "TimeProcessing" stat)?</p>
  
  <p>Furthermore, when I run the main report within BIDS (Visual Studio), the entire report returns in a couple seconds. Why would a report + 2 subreports render completely within a couple seconds in BIDS, yet the exact same thing takes around 20 minutes when viewed from the reporting server? They are both accessing the same SQL DB (data retrieval is only 140ms from SSRS server), and the SSRS/SQL server should have plenty of power (running in an 8-core VM that doesn't break 1% CPU usage).</p>