Empower "Server Busy TNS-12531" - WKB201290

SYMPTOMS

• "Server Busy TNS-12531 TNS:cannot allocate memory" error observed in Listener
• Windows: Oracle Net or Connections Via the Listener Fail with TNS-12531 on Windows 64-bit platform (Doc ID 1384337.1)
• It is possible that no other memory-related errors are being thrown at the same time
• It is also possible that the error is fleeting or seems to correct itself

ENVIRONMENT

• Empower 3 FR4
• Server 2012 R2 with 64 GB RAM

CAUSE

This can be caused by an inadequate setting for Desktop Heap Size.

Even if this is a 64-bit OS with a high amount of memory, there is still a limitation that generates this error.

FIX or WORKAROUND

1. Check and edit the Desktop Heap size located here in the registry:
2. Launch regedt32 and go to \HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\SubSystems\
3. In the right-hand pane, click on Windows and the pull-down Edit, and then select Modify.
4. You should see a string that resembles this in its entirety:
   %SystemRoot%\system32\csrss.exe ObjectDirectory=\Windows SharedSection=1024,20480,768 Windows=On SubSystemType=Windows ServerDll=basesrv,1 ServerDll=winsrv:UserServerDllInitialization,3 ServerDll=winsrv:ConServerDllInitialization,2 ServerDll=sxssrv,4 ProfileControl=Off MaxRequestThreads=16 
5. Focus on this section: Windows SharedSection=1024,20480,768
6. The third argument is the maximum amount of heap memory allocated to non-interactive desktops. Increase this third value and see when the TNS error disappears. There is no optimum value. It varies on each MS Windows server.
7. This change in the registry requires a restart of the Windows server in order for the change to take effect.
   
   IMPORTANT: ALWAYS back up the registry before making any changes.

ADDITIONAL INFORMATION

This error can also be caused when the memory is actually low. Check the resource consumption at the time of the problem. If there is no apparent memory shortage, the solution documented here may resolve the issue.