OutOfMemory exception

Question

1. What are the possible reasons of OutofMemory exception.

2. Memory allocations should be handled by GC.

3. How much memory is allocated/Available to normal .NET/C# application

In our application it comes at different places like Stream.ReadToEnd() and DataTable.WriteXml(Memory stream) function.

Environment is .Net C#

Answer 1

The OutOfMemory exception happens whenever a call to any of the following MSIL instructions fails

1. newobj
2. newarr
3. box

Which basically the operations that allocate new memory in the heap, in your case the Stream.ReadToEnd apparently allocates array of bytes internally to load the stream in memory, so if the file in big enough to break the process it will throw this exception.

Answer 2

Either you are using more memory than the app has available to it. In this case you will need to work out how to make your memory usage more efficient. Using Files / Database to store data you arent immediately using may be necessary..

Or, you have a memory leak. In which case you need to look at removing references to memory when you are no longer using them so the GC can free up the memory.

If you are using C# or .Net you can use the CLR Profiler to analyse your memory to see how it is being used. CLR Profiler