Labview hangs when using the DB Connectivity Toolset

[Martyn Clark]

I am working with my collegue Chris Barrett (see his earlier posts on this subject) on this problem and am currently trying to understand why the attached Vi is never able to complete its loop of 100 reads of a database table.

Its purpose is simply to connect to a database and then query a table and display two fields 100 times before disconnecting again.

The problem is that it never gets past 97 iterations before the Vi Hangs up. The failure is catastrophic forcing a reboot of the system.

I can see no conceptual reason why this Vi should not work but I will confess that my expertise is not in using LabView.

Whilst it is true that the Vi would not be used in its current form in the applicat
ion we are trying to develop (i.e. in this loop), the technique of reading a database in this manner certainly would be and we must therefore ensure that the system will not hang in
this manner.

We have been struggling with this problem for some time so any help you could provide would be greatly appreciated.

I am using Labview 6.0.2 (upgraded from v 6.0) and version 1.0 of the Database Connectivity Toolset.

[Crystal]

Hi, Martyn

I'd like to know more about your system. I was able to run your VI and it went through all 100 iterations quickly and without a problem.

Sincerely,
Crystal Drumheller
LabVIEW R&D

[Martyn Clark]

Hello Crystal,

Thanks for replying so promptly.

Its interesting that you managed to get the offending Vi to run OK on your system ... what happens if you bump the counter up to something more than 100 (eg 1000).

As far as my system is concerned I'm not sure what else to tell you. In addition to the versions of Labview and Database Connectivity Toolset already mentioned I am running on a 600 Mhz Pentium PC under Windows 98 second edition (4.10.222A) and have 256 MB of RAM.

If you need more information on my system then just ask me specific questions and I'll do my best to answer them.

Oh ... its possible that you may have already recieved a message from me say pretty much the same thing. If so I apologise for repeating myself I wasn't sur
e that I'd managed to send it

Martyn.

[Crystal]

Hey, Martyn

Well, your system sounds pretty normal, so I'm not sure what else to say. I ran your VI with 1000 iterations and it still had no problems. Here's my system: 850MHz laptop with 392 MB of RAM running Win2000. I'm also using Access2000 on the same machine. Is the database on your machine or over the network? I've seen some interesting things happen with networks. Since it's pretty quiet here today, I might jump on other machines to see if I can get some clue as to what might be the problem.

I'll also keep an eye on this to see if anyone else replies to you with clues that might help me.

Keep me informed,
Crystal

[Martyn Clark]

Crystal,

I've done some more investigation on this problem in light of your last response and have found that the problem manifests itself on a Windows 98 system.

At first wondered if there were problems with the JET 4.0 engine and investigations revealed that there was a indeed service pack 5 that could be installed (Lab view ships with service pack 4). Installation of this service pack did nothing to resolve the problem on a Windows 98 system.

Then I decided to install Labview onto a Windows 2000 system (without installing Jet 4.0 SP5) and ran the offending VI. It behaved as you described (including upping the nubmer of iterations to 1000)! For reference the W2K system was:

Dell Optiplex GX150
900 Mhz Intel proce
ssor
128 MB RAM
Windows 2000 Professional V 5.0.2195 Service Pack1 Build 2195

Other things to say are that the database has always been local .... no networking involved. Also, the W2K machine did not have Access 2000 on it.

Hope this extra information is of help in tracking the problem.

Martyn.

[Todd_Home]

I have just experienced a problem very close to this, and tracked it down (at least to the .vi where it hangs), which is NI's "Rec Get Value From Field.vi".

My app hangs after 4,000 to 7,000 iterations of data fetches. It doesn't seem to matter on the method I use (top level select vi, or vis to get each records at a time).

My app works _flawlessly_ with Win XP.

Based on the lack of activity, I have to ask, Is NI ever going to address/resolve this issue?

Todd