Don't Try To Handle What You Cannot Handle

One thing that came up last week was that the sorting on one of the paged grid did not work, ok…so we were hunting the bug down, but lucky something popped up in the log file and saved the day.
Clicking on the sort headers, makes a service call to retrieve the sorted data, and the UI code was written in such a way that the service call is trapped inside a try-catch block, and if any exception occurred, the exception is logged and empty data returned.

And unfortunately the service query had a bug on it. So which brings me to the point, you should catch exceptions only when you can handle it, for example, you might have anticipated that a DuplicateNameException would be thrown, well go ahead, catch it and show a nice message to the user, but if you cant, don’t put it inside a catch block and bypass the exception just for the sake of not crashing the UI.
If you really want to log it, fine, log it then remember to re-throw the exception although re-throwing as its own performance cost.

And to be amazed, the error was there al the time and no one noticed it, which brings to the justifiation the if you dont handel exceptions that you cant handle, you would have seen the issue so much earlier.

Comments

Hosting WCF services on IIS or Windows Services?

There came one of those questions from the client whether to use II7 hosting or windows service hosting for WCF services. I tried recollecting a few points and thought of writing it down. WCF applications can be hosted in 2 main ways - In a Windows service - On IIS 7 and above When WCF was first released, IIS 6 did not support hosting WCF applications that support Non-HTTP communication like Net.TCP or Net.MSMQ and developers had to rely on hosting these services on Windows Services. With the release of IIS 7, it was possible to deploy these Non-Http based applications also on IIS 7. Following are the benefits of using IIS 7 to host WCF applications Less development effort Hosting on Windows service, mandates the creating of a Windows service installer project on windows service and writing code to instantiate the service, whereas the service could just be hosted on IIS by creating an application on IIS, no further development is needed, just the service implementa

The maximum nametable character count quota (16384) has been exceeded

Some of our services were growing and the other day it hit the quote, I could not update the service references, nor was I able to run the WCFTest client. An error is diplayed saying " The maximum nametable character count quota (16384) has been exceeded " The problem was with the mex endpoint, where the XML that was sent was too much for the client to handle, this can be fixed by do the following. Just paste the lines below within the configuration section of the devenve.exe.config and the svcutil.exe.config files found at the locations C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE , C:\Program Files\Microsoft SDKs\Windows\v6.0A\bin Restart IIS and you are done. The detailed error that you get is the following : Error: Cannot obtain Metadata from net.tcp://localhost:8731/ Services/SecurityManager/mex If this is a Windows (R) Communication Foundation service to which you have access, please check that you have enabled metadata publishing at the specified address. F

Finalization, Know What it Costs

This is a post about object finalization in .NET. Finalization is not as inexpensive as we think, it increases the pressure put on GC.All objects that need finalization are moved into a finalizable queue and the actual finalization happens in a separate thread. Because the objects full state may be needed, the object itself and all the object it points to are promoted to the next generation (this is needed so that GC does not clean these objects off in the current round), and these objects are cleaned up only after the following GC. Due to this reason, resources that need to be released should be wrapped in as small a finalizable object as possible, for instance if your class needs a reference to an unmanaged resource, then you should wrap the unmanaged resource in a separate finalizable class and make that a member of your class and furthermore the parent should be a non-finalizable class. This approach will assure that only the wrapped class (class that contains the unmanaged resourc

Nairooz Nilafdeen's Blog

Search This Blog