Cannot quit Visual FoxPro (Windows Terminal Server 2008 + Citrix XenApp 5 + VMWare vCenter 5.1)

Question

Hi everybody:
This is not the typical question about this error, because the problem here is not about how to quit (CLEAR EVENTS then QUIT). The really and weird problem is that our application do no execute the error trapping routines (Try/Catch and ON ERROR) and tries
to directly Quit.
I have never seen something like this before, error trapping routines not executed.
I try to explain the problem better:
- The user click on the Citrix icon of our App
- Citrix shows the executed processes (establishing connection, applying user config, loading profile, etc)
- The Application (VFP 9 SP2) is started and in any moment, while loading, occurs an error that is not handled by error handlers, and it executes a "kind" of a Quit command, that we detect because have a ON SHUTDOWN to catch it, then the App shut
down and the user must click the Citrix icon and start all over again, up to 7 times, when the App really load and work.
- I think that it is useful to make clear that no QUIT command is really causing this, just the behaviour of the QUIT when an error occurs, but just while loading. If the App get completely loeaded, then everything works as expected
Infraestructure:
- Windows Terminal  Server 2008 + Citrix XenApp 5 + VMWare vCenter 5.1
- There are up to 50 concurrent users max in every virtualized server
- More than 10 GB of free disk space / Up to 4 GB ram
- RAM Memory is never used to the max
- CPU (Intel Xeon) is never used to the max (up to 90% in some cases)
- Data (DBFs for temporal work) ar on local drive, not over network (to avoid network known problems with smb2-3)
- There are connection to a Oracle 11 database for permanently storing the data
About the errors:
- They are not always the same or in the same place. In example, in one execution could fail the query of SET("Printer",2), in other execution could fail a SET PROCEDURE TO xxx ADDITIVE (sometimes already loaded), in other could fail a "DO
WHILE .T." in a init event.... completely crazy, and in all cases the errors are not thrown, not a single error code, the App just try to quit, as if ALT+F4 where pressed.
- All this does not happen allways to everyone, but happens many times in the day to many many users as to be worried
- The same user can have this error many times a day, but not allways
- Some of the problems started when migrating to Windows Terminal Server 2008, but didn't notice nothing special in the beginning, but a year later (last 2014) problems tend to go worse
Tried solutions:
- For the "SET PROCEDURE TO xxx ADDITIVE" error, a "IF xxx $ SET('PROCEDURE')" check was added
- The "SET('Printer',2)" check was moved out of initialization code, so it executes when user want to print the first time. In this case was neccesary to talk with IT guys to map a default printer after the App runs, and not in background, as it
was.
- Other checks and modifications was made to minimize posibility of errors
- Adding a timeout of 5 secs in the start of the program, to force a wait
- Restart of virtual servers (not the phisical) every 3 weeks
What I suspect:
- Some Microsoft optimization (memory?, process execution?) in WTS-2008 may interfere?
- Some VMWare memory management may interfere with WTS-2008?
- Some Citrix management may interfere with both?
- Server degradation because of day to day use
Results until now:
- Apparently, adding the timeout to force 5 secs delay and the restart of the server have made a notable enhancement in App start and running
with far fewer
errors
Has
this happened to anyone?
Thanks! o_O
Fernando D. Bozzo / Madrid (Spain)

Answer 1

I never had this type of problems, but somewhat similar start up problems. I'd say it indicates resource problems. Low RAM can cause many unpredictable things. In my case loading much data at the begin of an application caused out of memory errors, which
were reported and logged normally, though.
I made a small tool using Windows API functions GetPerformanceInfo and GetProcessMemoryInfo, you'll find declaration and usage like usual at the News2News site. It's a bit lengthy and cluttered, but pretty much what you find there anyway, so I'll not post
my utility code.
I could quite clearly see how many users degraded available memory per session and at some time no further instance of the application was possible on the server. In my case RDP was used to start the app, Citrix will be quite the same, in the end the application
runs on some server and users see the remote running application.
Bye, Olaf.
Olaf Doschke - TMN Systemberatung GmbH
http://www.tmn-systemberatung.de