I have read this article: http://blogs.msdn.com/b/oldnewthing/archive/2010/08/10/10048149.aspx and honestly I don't understand every detail. As far as i understand in the code below c should be collected even if i don't set c to null. Another thing is that allocations happening during a foreach seem to be not freed as long as we in the scope of the same function. (See example below)
class Program
{
public class SomeClass
{
public byte[] X;
public SomeClass()
{
X = new byte[1024 * 1024 * 100];
X[155] = 10;
}
}
static void Main()
{
Console.WriteLine("Memory: " + GC.GetTotalMemory(false));
SomeClass c;
c = new SomeClass();
Console.WriteLine("Memory: " + GC.GetTotalMemory(false));
GC.Collect();
Console.WriteLine("Memory: " + GC.GetTotalMemory(true));
Console.ReadKey();
/*
* Output:
*
* Memory: 186836
* Memory: 105044468
* Memory: 104963676
*
*/
}
}
EDIT The solution for the first example: The Debug-Mode (not running in debugger but even the compilation-mode). If I use Release it'll work as expected: c is collected even without setting to null. For Second example the same applies.
Second example
static void Main(string[] args)
{
Console.WriteLine("Startup Memory: " + GC.GetTotalMemory(false));
var obj = BOObject.Get();
Console.WriteLine("Fetched Object: " + GC.GetTotalMemory(false));
GC.Collect();
Console.WriteLine("Fetched Object (Collected): " + GC.GetTotalMemory(false));
foreach (var node in obj.Traverse())
{
string name = node.Name;
}
Console.WriteLine("Traversed: " + GC.GetTotalMemory(false));
GC.Collect();
Console.WriteLine("Traversed (collected): " + GC.GetTotalMemory(false));
obj = null;
GC.Collect();
Console.WriteLine("collected: " + GC.GetTotalMemory(true));
Console.Read();
}
Output:
Startup Memory: 193060
Fetched: 8972464
Fetched (Collected): 5594308
Traversed: 272553096
Traversed (collected): 269564660
collected: 269564048
If i put the foreach loop in another function and call this function the memory used after .Collect is call is about 5800000. So why the garbage is not collected when i have the foreach loop in the same function?
See Question&Answers more detail:
os 与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…