We have a ASP.Net web application which runs on .Net framework 4.0.
Architecture is like,
.Net Module --> VB6 COM+ Data Object --> VB6 COM+ Calculation Module --> 3rd party COM+ Finance Factory (installed COM).
End user uses this application to create contracts by collecting customer details, vehicle details, finance details and calculate multiple parameters in a single calculate button click then submits all the data to another system.
Issue: Intermittently, it is throwing ‘Out of Memory’ error while calculating the deal (on clicking calculate button on the deal) and calculation is not being completed successfully. This impacts the business. We found that it is being thrown in the VB6 COM+ Calculation Module -> in a Initialize method.
This method is initializing the third party (installed) COM objects and feeding the necessary data for calculation in xml format (Predefined), immediately getting back the response and ending the subroutine.
We got to know that this error is happening inside this method only and not sure about which statement is causing this. And this happening in Production environment alone. No other (test) environments are able to be replicated.
It is high risk to have any logs over this method and redeploy the code into Production and hence we are unable to have any log information over here. It was an issue since beginning but happens very occasionally but it became frequent since past 6-8 months.
Error message: Sub: Initialize
Error Number: 7
Error Description: "Out of memory"
Environment detail: Windows 2003 Server SP 2 with 3 GB of Physical memory. Our application COM objects are built with Apartment Thread model and registered within MTS.
We carried out Load test, stress test but still unable to replicate the issue. And hence we are unable to find the root cause as well. We had spent good enough time on this and still struggling.