I want to be certain that a WCF service running as a standalone executable (or windows service) cannot crash.
In case it wasn't obvious, I'm looking for more than a yes or no answer.
Yes. It can run out of disk space or memory space. Or some application with protected access can come along and corrupt it's memory. The CPU could experience an intermittent hardware failure that results in some otherwise impossible set of variable values that lead to a crash. They'res a myriad of possible though unlikely scienarious that could cause it to crash unexpectedly.
In my experience, these usually die because of bugs in the code or lack of exception handling around accessing resources external to the running process. I.E. Files, Database, Web-services, etc.
Spencer's assessment accounts things you cannot control.
Related
I am a self-taught programmer and have only delved into new areas of programming as the need arises. I have never done any network programming, everything I have written has been for a single computer. I have written a program for an old board game and it runs great. But, now I want to try to write it to run for multiple players across a local network. I have an idea of what has happen in terms of constantly checking a specified folder/file for changes. But... how do you test this without actually building/compiling the program and installing it on another computer every time you make any changes? I have tried to search various forms of what I have as the title here, but all that comes up is about testing network connections, or socket programming (would this be easier/needed) or systemfilewatcher (which may be an option too if it will run on Windows 7 and 10... but, I find nothing about testing programs to actually access the network and simulating 2 copies of the program running. Any suggestions, links, etc. would be greatly appreciated.
I think you will be disappointed in the performance of a file-based network game unless reaction or refresh time is of little consequence for your "board" game. You may also need to work out potential concurrency issues (ie, someone updating a file you've just read). If you have any desire to do other games in the future you should be using sockets (most likely UDP unless you have a good reason not to) to create a client server system.
As to your question, yes, you should be able to test it. You just need to run both a compiled exe and the source in VS debug mode, accessing the same folder on your drive. If you go with the socket-based option, you would use your PC's loopback address 127.0.0.1 (sometimes known as localhost), but the 2 different parts will need to communicate on different ports.
In my understanding a process is,
"an operating system level concept used to describe a set of resources (such as external code
libraries and the primary thread) and the necessary memory allocations used by a running application.
For each *.exe loaded into memory, the OS creates a separate and isolated process for use during its
lifetime." -Andrew troelsen (pro c# 2010)
so each time we start an application a process is created with its own address space which cannot be shared by other process.
recently i have read in clr via c# that,
"The CLR does, in fact, offer the ability to execute multiple managed applications in a single
OS process. Each managed application executes in an AppDomain."
this says that multiple apps can run inside a single OS process, is there a difference between OS process and the process that is started when we run an application???
can someone shed light on this please.
The difference is that the primary running process is managed by the operating system. The CLR/Framework offers a completely different stack known as "application domains" that allows separate running instances of a program to be executed under the same system-level process but act as completely independent processes. Not being an expert on C#/.NET model of design, I cannot facilitate an example of where this might be useful other than scalability of large systems.
I am getting a System.OutOfMemoryException from my vb.net application, it happened from one certain user. I am trying to figure out whether my application takes too much memory space or the PC has low memory. But she just upgraded her desktop as i3 Intel CPU and higher memory.
Is there any tool that I check memory consumption when code is executed as go through lines?
By the way, it is developed by vs2010 and It is a Windows application.
<--Edit-->
I found the problem from my application. I did not mention because I did not know what the problem was. I am using a Google map inside of vb.net application. It takes a memory whenever I search a map on web browser which is on a form . Even though I close the form, it is not disappeared from
memory. It is just going up. That goes away when I close MDI form. FYI..
The best tool we've worked so far is the JetBrains profiler (http://www.jetbrains.com/profiler/features/).
That's a common error. It normally happens when the application enters a loop that never ends... (infinite loop).
Is it a Console, WinForms, ASP, WPF?
Try to identify during which Event your application throws the exception and put a try catch to print out more details.
Just check out this cool WPF performance suite to check out if you have memory leaks:
Performance Toolkit
Or check out if you can use GC.Collect() to find the leak.
Also you can accecss in Process Explorer to any .Net memory data and peaks.
Regards
I am getting Out of Memory errors in classic ASP, probably where attempting to access data. For example:
Microsoft VBScript compilation error '800a03e9'
Out of memory
(some file) Line 0
These errors only happen once in a while and they keep happening for a few minutes and then the webserver must be restarting the app pool because all sessions are lost.
What is a good tool for finding/diagnosing memory leaks in a classic ASP application that makes heavy use of ADO for data access and a couple of other off the shelf COM objects.
Presumably any memory leaks would be from the COM object rather than the script, so a general Windows debugger or leak finder might be what I need. Any advice on what would be appropriate?
Or any other thoughts on what might cause these errors?
Unfortunately, tracking down memory leaks is not an easy task :-(
Here's a good summary of things to watch out for here:
http://www.leinadium.com/code/classic-asp-memory-leaks-in-iis/
Be sure to read the link inside that post as well for a list of tools.
Good luck!
Microsoft has a good utility umdh.exe that may be good for finding leaks in this situation. It allows you to take a "snapshot" at one point, exercise the application (e.g., IIS) then take another snapshot and compare the memory usage differences.
if
you try to get one row data with EOF OR BOF
or
the database connection is close or readony you try to wirte!
you should get the ERROR.
I've used the CF Remote Performance Monitor, however this seems to only track memory initialised in the managed world as opposed to the unmanaged world. Well, I can only presume this as the numbers listed in the profiler are way short of the maximum allowed (32mb on CE 5). Profiling a particular app with the RPM showed me that the total usage of all the caches only manages to get to about 12mb and then slowly shrinks as (I assume) something unmanaged starts to claim more memory.
The memory slider in System also shows that the device is very short on memory. If I kill the process the slider shows all the memory coming back. So it must (?) be this managed process that is swallowing the memory.
Is there any simple(ish?) fashion how one can track unmanaged memory usage in some way that might enable me to match it up with the corresponding P/Invoke calls?
EDIT: To all you re-taggers it isn't .NET, tagging the question like this confuses things. It's .NETCF / Compact Framework. I know they appear to be similar but they're different because .NET rocks whereas CF is basically just a wrapper around NotImplementedException.
Try enabling Interop logging.
Also, if you have access to the code of the native dll you are using, check this out: http://msdn.microsoft.com/en-us/netframework/bb630228.aspx
I've definitely been fighting with unmanaged issues in a C# managed app for a while -- it's not easy.
What I've found to be most helpful is to have a regular output to a text log file. For example you can print the output of GlobalMemoryStatus every couple of minutes along with logging every time you load a new form. From there you can at least see that either memory gradually erodes, or a huge chunks of memory disappeared at specific times of the day.
For us, we found a gradual memory loss all day as long as the device was being used. From there we eventually found that the barcode scanning device was being initialized for no particular reason in our Form base class (I blame the previous developer! :-)
Setting up this logging may be a small hassle, but for us it paid huge dividends in the long run especially with the device in live use we can get real data, instrumentation, stack traces from exceptions, etc.
Ok, I'm using C++ on CE, not C# so this may not be helpful, but...
I use a package called Entrk toolbox which monitors memory and resource usage, leaks, and exceptions under Windows CE. Pretty much like a lightweight CE version of boundschecker. Does the trick most times.