Windows desktop heap may cause hang of TcServer processes

If you are planning to run large numbers of processes using Microsoft Services, you will likely run out of non-interactive desktop heap resources. A limitation exists in the size of the Windows desktop heap that effectively limits the number of processes that the server manager can manage. When this particular heap allocation is consumed, processes may hang in several ways (including during execution of a child process). If the TcServer process hangs after spawning any new subprocess, the client appears hung to the user. Everything may work fine on a system that is not heavily populated with large numbers of TcServer processes. The size of the desktop heap is independent of the amount of RAM installed. The size of the desktop heap is by default smaller for processes started with services, so this is more likely to be encountered when Teamcenter server manager is started as a service. The Microsoft NtDebugging Blog article Desktop Heap Overview provides more information regarding this resource. On some operating systems, a default non-interactive heap setting of 768 for the SharedSection settings results in limitations of about 100 TcServer processes for a server pool started as a Windows service. If you encounter this limitation when running the server manager pool as a service, you can work around it by starting the server manager from a user console. The desktop heap SharedSection registry values associated with an interactive window are by default many times larger than the SharedSection associated with a non-interactive window service. For example, on a Windows 7 machine, the value is: Copy SharedSection=1024,20480,768 If you have no other recourse, you may carefully modify the controlling registry values per the Microsoft Knowledge Base article 184802. Caution Pay close attention to the risks of modifying these particular registry values spelled out in the article. If not done properly, you may have to reinstall the operating system (OS). You should only edit the third value of the SharedSection value, which is the value associated with non-interactive desktop heap. If you run a 32-bit OS (only applicable for earlier versions of Teamcenter on 32-bit), the boot.ini setting of /3GB for a 32-bit OS should not be used with modifications to this registry setting, because it causes the first value of the SharedSection (for SessionViewSize) to be ignored. Setting /3GB after this registry has been edited may make the system unusable. When editing this registry value, Siemens Digital Industries Software recommends that the third value for non-interactive desktop be increased in small increments such as 512 until the processes started with services run well. You should not have to increase it larger than the second value of the SharedSection that applies to interactive desktop heap.