Datasnap client application hangs

Question

I have written an application which uses a Datasnap Server over TCP installed as a windows service, and a VCL Winform client using Delphi 2010. The server application is connecting to a SQL Server 2008 instance on the same box. Everything works fine and dandy when I have one user logged in, as soon as a second user connects they both start to get program not responding. I thought that the problem may be a bottle neck in some queries in SQL but I have run a trace all day long and do not see any problems. I subsequently found that an older version of the midas.dll was installed, so I updated that to a later version. But still no joy. I am not sure where to start looking for the problem. I used Bob Swart's Data how you want it white paper as my guide to producing a Datasnap Server and Client, and on a smaller implementation it seemed to work fine. Any pointers on where to start looking would be very much appreciated, before I revert the application back to a thick client and rewriting the server as a .net WCF service using Entity Framework etc etc.

Answer 1

如此处http://blog.marcocantu.com/blog/datasnap_webinar_bedelphi_material.html所述，这可能与多线程问题相同。它描述了如何在Delphi XE3中修补DataSnap，但与在先前版本（如XE）中发现的错误相同。