I began working on an existing reporting solution on VS2008 three days ago. The reports take about 5-50 seconds for the query (depending on the complexity) and then a couple of seconds to render/calculate. Some of them are just tables, and some actually aggregate stuff from the underlying dataset.
However, all these reports executed/rendered within a reasonable amount of time. They were deployed to the customer quite some time ago, so I would call all those reports mature and working.
Now, I had to install the SSDTBI_VS2012_x86_ENU.exe (BIDS-Tools) yesterday on my Windows 7 (8GB RAM) desktop PC. After installing, quite a few updates had to be installed as well.
Now, when trying to render the same report, it takes about 10-15 minutes(!) using VS2008 and forever on VS2012. I haven't let it run overnight, but I doubt that it will work. What I see in the preview pane after hitting the 'View Report' button is the 'Loading' spinner dialog.
Of course, I started SQL profiler just to make sure that it's not the server blocking the output (the server runs on another machine). Nope, all queries are delivered in time. Hmm. I also removed all 'data' files, restarted VS, restarted the PC, went to lunch, had a coffee. All those dirty tricks. No change.
The task manager shows devenv.exe (VS2008) or the PreviewProcessService.EXE (VS2012) to occupy 13% in total on an 8-core, which is quite similar to a 100% CPU load (but is spread over 4 CPU. There is some disk I/O as well and these processes happily consume and free RAM quite frequently. So I guess, rendering is going on but at atomic level, I guess.
If I create a new report with the same query but a single tablix with one column, no grouping no nothing, it 'works', i.e. the report is rendered fast enough.
To make sure that it's not me having modified the RDL by accident, I used the original and working files from the ZIP that was handed to me and tried to preview them on VS2008: It still takes 15 minutes. Same machine. Yesterday 15 secs, today 15 minutes.
Now my question: Is this a known problem? What can I do to fix this? I read about hints to exclude the report elements, but ... there is only one tablix. Excluding it works, including it gives the endless loop. Is the only solution to recreate the report?
What is going on here? Any ideas?
EDIT: The reason is very simple: The reports are very complex (row groups and column groups) and calculating takes very long. VS2008 is much faster here than VS2012. So VS2012 does get the job done, but much slower than VS2008
