Not axactly a memory leak but can be bad

[Zeng]

From this paragraph:

Garbage collection is triggered in .NET either by application shutdown, heap
exhaustion, or an explicit call GC.Collect(). With the exception of
application shutdown, however, garbage collection only occurs when the
execution path reaches a safe point.

Does that mean it's possible for my process to get recycled for reach memory
max% even though most of the memory counted as used is no longer needed by
my app and it is not freed because GC hasn't gotten a chance to do so
safely? If that's true, sounds to me that having a finalizer in my class or
not would only *reduce* the chance of that occuring, but not eliminating, is
that accessment accurate to you?

I guess it's time for me to make my apologies. The point of my mentioning
Safe Points was to illustrate the workings of the GC.

Safe Points are points in the code that have been identified as it being
safe for the GC to suspend ALL threads in order to do its thing.

A problem faced by the GC is that when compacting the heap it must make sure
that it does not change the structure of the object graphs (internal
tree-like structures used for determining reachable/non-reachable objects
i.e. referenced/non-referenced objects), nor should it change the structure
of the heap. In order to achieve this, the GC is responsible for maintaining
object references (i.e. adjusting references within objects contained within
the graphs), because of course, when an object is moved in the heap, any
existing references to that object will be invalid. The only safe way to cope
with this is to suspend all application threads during garbage collection. It
is for this reason that the JIT compiler inserts Safe Points into the code,
i.e. points in the execution path that are safe for thread suspension.

Garbage collection occurs by the GC effectively "hijacking" the thread by
inserting a different return address from the safe point. When GC is
complete, .NET sends the thread back to its original return address and
normal execution continues.

Garbage collection is triggered in .NET either by application shutdown, heap
exhaustion, or an explicit call GC.Collect(). With the exception of
application shutdown, however, garbage collection only occurs when the
execution path reaches a safe point.

IMPORTANT NOTE :
================

When the GC has determined that an object is in fact garbage, the first
thing it does is check the object's metadata, and if the object implements
Finalize(), instead of destroying the object, it is marked as reachable
(which is not what you want if you want your object to be destroyed
immediately) and is moved from its original graph to another graph called the
"finalized queue". A seperate thread then iterates over the finalized queue
invoking Finalize() on all objects contained therein; then -and only then-
are the objects removed from the queue and destroyed, hence freeing up its
heap space.

So, essentially, when you implement Finalize() you are telling the GC that
when the object is no longer referenced it is NOT SAFE for deletion YET, and
Finalize() must first be invoked, which means that the object is not
destroyed for approximately two runs of garbage collection. It is for this
reason that deterministic finalization is recommended.

EXPLICIT garbage collection is not recommended becuase it is an expensive
operation involving scanning object graphs, thread suspension and resumption,
thread context switches, and EXTENSIVE use of reflection to read the objects'
metadata.

I hope that that clears up the confusion I might have injected into the
discussion, also, I hope it clears up why you should not declare a finalizer,
even if there is no body. The simple act of declaring a finalizer ensures
that the object lives for longer than you might actually intend/require.



--
Of all words of tongue and pen, the saddest are: "It might have been"

Bill.Richards @ greyskin .co .uk
http://greyskin.co.uk

I'm not sure on what you mean by "there is no documentation
available...because they don't apply here...". The existance of a document
doesn't depend on what part of version of my code was posted. I appreciate
your help looking into this for me, many people would just ignore posts and
move on even they know the answer or have some comments, but I don't think
we are going anywhere with it. My response was to BillR who proposes that I
should be implementing the IDisposable.

It's the production environment, if the process get recycled, all my cache
in the memory will have to be reloaded when it goes back up. That would
cause delay to the service that we want to provide. Sounds like you are not
familiar with the processModel entry with attribute memoryLimit="60" as
default, it's in the machine.config file. thanks!

Again, you don't have to implement IDisposable when you don't deal with
managed resources. What do you expect to do in your Dispose method? And No
there is no documentation available on Safe points, because they don't apply
here (at least not in the code snip you've posted).
I'm also not clear on what you mean with recycling the asp.net

process,
is

this something you intend to do or is it something that you are

expecting
to

be done automatically, anyway before the asp.net process recycles, all
application domains get unloaded, and this implies a GC run and a finalizer
run, so all objects (still referenced too) will be collected , but

even
when

some objects aren't collected, all memory once allocated for the process
will return to the OS when the process ends. So what are you afraid of?


Willy.

Relying on IDisposable won't work easily in the multi-threading scenarios.
Since the memory required for each object is big, I have put them on
static
variable to share it among the servicing threads. Think of CMyClass is a
spell-grammar-checker that helps looking up things and provide suggestions
for correction for many users create their documents online. In this
scenario, looks like there is the only choice
--> Make CMyClass disposable and create managing component (internal or
external to the class) just to coordinate when and which objects are done
just to call Dispose. This sounds like the intensive plumbing and
error-prone approach that I was so used to with C++

Conceptually, this is the drawback of a smart system, the programmer knows
what he/she needs to be done but can't change its behavior (which is very
very smart most of the time)

By the way, where can I find a documentation about the safe-points?
Wouldn't that be better that there is a call to wait for the system

to
be

done with collection and there is a safe point in that method? And is
there
a safe point in the component that checks for memory usage and

recycle
the

aspnet process when 60%(default) is reached?



and just to add my two pennies worth ...

Although you may call GC.Collect(), much the same as in Java when

you
try

to
force the VM to run garbage collection, it will still run at it's
earliest
convenience.

During compilation, your code is injected with "safe points"

whereby
the

GC
can hijack the thread and take control to do its work. Now, when

you
call

GC.Collect() your code might not be in a stable enough state for the GC
to
run, and the only way that the GC can know that it is safe to run is if
it
has reached a "safe point".

Generally speaking, it is bad practice to call GC.Collect() since you
will
inadvertantly interrupt a perfectly (or near to) working system,

and
you

yourself can cause all sorts of naughtiness to occur.

My choice of preference (as it is for a lot of developers) is to
implement
IDisposable.

AND, yes, our code should be easily readable and left in a state that
renders it possible for future devlopers to look at it and see what is
going
on (for maintenance reasons, or whatever), however, designing our classes
"off centre" just in case, the next developer doesn't know as much

as
us

is a
pretty poor choice IMHO.

--
Of all words of tongue and pen, the saddest are: "It might have been"

Bill.Richards @ greyskin .co .uk
http://greyskin.co.uk


:


I finally narrowed down my code to this situation, quite a few (not
all)
of
my CMyClass objects got hold up after each run of this function

via
the

simple webpage that shows NumberEd editbox. My memory profile shows
that
those instances survive 3 rounds of GC collections - it's not what I
expected. In my real code, CMyClass occupies big amount of

memory
and

they
all share one stance of another class that I don't have enough memory
hold
more than a just a few in the memory. Notice that the

finalizaer
the

my
CMyClass makes a big difference in demonstrating this issue, w/o

it
the

problem doesn't exist. The interesting thing is if I run the page
again,
the old dangling ones got destroyed and the new ones become dangling.
Am
I
missing something about the GC? Do I need to explicitly implement and
call
dispose for these classes instead of relying on GC to promptly collect
it?
Apparently somehow these objects can survive the automatic
collections...disposing it would help. Thanks for your comment and
help.

internal class CMyClass
{
ArrayList m_array = new ArrayList( 50000 );
private string m_idStr;
private Guid m_guid;
internal CMyClass( int n )
{
for( int i = 0; i < n; ++i )
m_array.Add( Guid.NewGuid() );

m_guid = Guid.NewGuid();
m_idStr = m_guid.ToString();
}

internal Guid id
{
get{ return (Guid ) m_array[ 0 ]; }
}

~CMyClass()
{
// Trace.Write( m_guid, m_idStr );
}

}
private void RunBtn_Click(object sender, System.EventArgs e)
{
ResultEd.Text = "";
try
{

for( int i = 0; i < int.Parse( NumberEd.Text ); ++i )
{

Hashtable table = new Hashtable( 100 );
ArrayList ids = new ArrayList( 10 );
for( int j = 0; j < 10; ++j )
{
Guid id = Guid.NewGuid();
table[ id ] = null;
ids.Add( id );
}


for( int k=0; k < 10; ++k )
{
foreach( Guid id in ids )
{
table[ id ] = new CMyClass( 10 );
}

CMyClass myobj;
foreach( Guid id in ids )
{
myobj = (CMyClass) table[ id ];
myobj.id.ToString();
}
} // for k
} // for
}
catch( Exception ex )
{
ResultEd.Text = ex.Message + "...CallSTack:" +
ex.StackTrace;
}

GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();

GC.WaitForPendingFinalizers();
GC.Collect();

ResultEd.Text = "Done";
}

 

[Zeng]

I'm asking you the same question as I have asked BillR:

Is it possible for my process to get recycled because it reaches memory
max% even though most of the memory counted as used is no longer needed by
my app and it is not freed because GC hasn't gotten a chance to do so
safely? If that's true, sounds to me that having a finalizer in my class or
not would only *reduce* the chance of that occuring, but not *eliminate*, is
that accessment accurate to you?

By the way, I hope I don't need to correct all my mis-understanding what the
GC is meant for to raise that question.

Seems like you have a fundamental mis-understanding on what the GC is meant
for and how it's actually performing.
The GC's task is, to collect the memory space occupied by non-reachable
objects and compact the generation it is actually collecting, so that a
contiguous free space remains in the heap to add new objects.
A full GC is a GC run that collects all generations, the current version of
the CLR has 3 generational logical heaps plus a separate large object heap
(LOH), from code you can ask for a GC run by calling GC.Collect(n) where n
indicates the generation to end with, a collection always starts with
generation 0.
GC.Collect() collects all generations plus the LOH, that's why it's called a
full collect.

However, it's NOT the task of the GC to bring down the heap size, that's the
task of the CLR memory manager , or the hosting process memory manager (if
any) in close cooperation with the OS.

Your code sample needs at least two GC.Collect() calls, that's because you
have a Finalizer (destructor in C# parlance).
When an instance of a finalizable object gets instantiated, it's registered
as finalizable.
When it is no longer rooted at the next GC run, it will be moved to the
finalizable queue, where it stays until after the finalizer has run, after
which it's removed from the finalizer queue and it becomes eligible for
collection.
Note that it's possible that not all finalizables are immediately finalized,
all depends on the load of the system and the time the finalizer thread
spends finalizing objects. The finalizer thread can be suspended before all
finalizer have run, that's why we say at LEAST 2 GC runs, and why we suggest
against destructors in C#.

Willy.

PS I suggest you start reading these (somewhat outdated) articles , before
you start arguing about a subject you don't seem to fully understand.
http://msdn.microsoft.com/msdnmag/issues/1100/GCI/default.aspx
http://msdn.microsoft.com/msdnmag/issues/1200/GCI2/default.aspx

From what I understand, Dispose method doesn't help freeing manage
resources, and that's consistent with what you are saying.

About the hosting process tries to do a full GC run before it recycles
based
on MemoryLimit%; I don't believe it at this point, if there is such thing
as
full GC and it's doing what we expect, then it should have been exposed so
we - developers - can call it when we need to bring down the heap size
immediately (of course we don't need this if full GC is actually possible
privately to the framework, but I don't believe it). How many times
should
I try to call GC.Collect to free the dangling objects in my demo code?
And
if GC.Collect doesn't do what "Collect" means, what is its use? Purely
advertising?

Imagine somebody sell you a cabinet and there is knob on it, and he tells
you that yes that's a knob but don't use it, you NEVER need or want to use
it. If you actually never need to use it then it should be only for
decoration but that was only a speculation - and one day you decide to
pull or turn it, and it doesn't do anything ... hahaha who is more insane,
the person tries to use the knob or the person put the knob on the cabinet
and didn't think it's for decoration??

Sorry what I meant was ""there is no documentation ... AND they don't apply
here". If you need more info on GC safe points I'm afraid you'll have to
look in the source code files of the CLR if you happen to have a Source Code
License. Anyway, when your code calls GC.Collect it's always at a safe GC
point, it's only when a GC is "induced" that it might get postponed when
your code is not at a GC safe point.
What Billr proposed makes little sense in your case because your class don't
own unmanaged resources, like DB connections, unmanaged memory OS handles
etc..., it only consumes managed heap memory which is taken care of by
the
GC, there is no need to force collections by calling GC.Collect yourself.
But if you really think you have to implement IDisposable, go ahead, but
please tell us what you will do in your Dispose method.

I guess I'm more familiar with the process model than you might think.
The
asp.net hosting process recycles when it's Working Set exceeds the
memoryLimit% of total available memory, but the hosting process will

try
to

survive first by forcing a full GC run, followed by an attempt to

reduce
the

working set, then and ONLY when it's WS still exceeds the MemoryLimit% it
will recycle, else it simply continues to run.
In case the WS could not be reduced it's simply because an application
hosted in asp.net allocates too much memory or as a result of heap
fragmentation (take care when allocating many large objects (>85Kb)),

or
as

a result of a design error.
When it happens on a production system, it must be considered an application
error , because the memoryLimit%, available system memory, number of active
clients etc.. should have been defined during staging, when you performed
your load/stress testing and your workload modeling.

Willy.

I'm not sure on what you mean by "there is no documentation
available...because they don't apply here...". The existance of a
document
doesn't depend on what part of version of my code was posted. I
appreciate
your help looking into this for me, many people would just ignore posts
and
move on even they know the answer or have some comments, but I don't think
we are going anywhere with it. My response was to BillR who proposes that
I
should be implementing the IDisposable.

It's the production environment, if the process get recycled, all my cache
in the memory will have to be reloaded when it goes back up. That
would
cause delay to the service that we want to provide. Sounds like you
are
not
familiar with the processModel entry with attribute memoryLimit="60" as
default, it's in the machine.config file. thanks!


Again, you don't have to implement IDisposable when you don't deal
with
managed resources. What do you expect to do in your Dispose method?
And
No
there is no documentation available on Safe points, because they don't
apply
here (at least not in the code snip you've posted).
I'm also not clear on what you mean with recycling the asp.net process,
is
this something you intend to do or is it something that you are expecting
to
be done automatically, anyway before the asp.net process recycles,
all
application domains get unloaded, and this implies a GC run and a
finalizer
run, so all objects (still referenced too) will be collected , but
even
when
some objects aren't collected, all memory once allocated for the process
will return to the OS when the process ends. So what are you afraid
of?


Willy.

Relying on IDisposable won't work easily in the multi-threading
scenarios.
Since the memory required for each object is big, I have put them on
static
variable to share it among the servicing threads. Think of

CMyClass
is

a
spell-grammar-checker that helps looking up things and provide
suggestions
for correction for many users create their documents online. In
this
scenario, looks like there is the only choice
--> Make CMyClass disposable and create managing component

(internal
or

external to the class) just to coordinate when and which objects are
done
just to call Dispose. This sounds like the intensive plumbing and
error-prone approach that I was so used to with C++

Conceptually, this is the drawback of a smart system, the programmer
knows
what he/she needs to be done but can't change its behavior (which is
very
very smart most of the time)

By the way, where can I find a documentation about the safe-points?
Wouldn't that be better that there is a call to wait for the

system
to

be
done with collection and there is a safe point in that method? And
is
there
a safe point in the component that checks for memory usage and recycle
the
aspnet process when 60%(default) is reached?



and just to add my two pennies worth ...

Although you may call GC.Collect(), much the same as in Java when you
try
to
force the VM to run garbage collection, it will still run at it's
earliest
convenience.

During compilation, your code is injected with "safe points"
whereby
the
GC
can hijack the thread and take control to do its work. Now, when
you
call
GC.Collect() your code might not be in a stable enough state for
the
GC
to
run, and the only way that the GC can know that it is safe to run
is
if
it
has reached a "safe point".

Generally speaking, it is bad practice to call GC.Collect() since you
will
inadvertantly interrupt a perfectly (or near to) working system,
and
you
yourself can cause all sorts of naughtiness to occur.

My choice of preference (as it is for a lot of developers) is to
implement
IDisposable.

AND, yes, our code should be easily readable and left in a state that
renders it possible for future devlopers to look at it and see

what
is

going
on (for maintenance reasons, or whatever), however, designing our
classes
"off centre" just in case, the next developer doesn't know as

much
as

us
is a
pretty poor choice IMHO.

--
Of all words of tongue and pen, the saddest are: "It might have been"

Bill.Richards @ greyskin .co .uk
http://greyskin.co.uk


:


I finally narrowed down my code to this situation, quite a few (not
all)
of
my CMyClass objects got hold up after each run of this function via
the
simple webpage that shows NumberEd editbox. My memory profile shows
that
those instances survive 3 rounds of GC collections - it's not
what I
expected. In my real code, CMyClass occupies big amount of
memory
and
they
all share one stance of another class that I don't have enough
memory
hold
more than a just a few in the memory. Notice that the
finalizaer
the
my
CMyClass makes a big difference in demonstrating this issue,

w/o
it

the
problem doesn't exist. The interesting thing is if I run the
page
again,
the old dangling ones got destroyed and the new ones become
dangling.
Am
I
missing something about the GC? Do I need to explicitly implement
and
call
dispose for these classes instead of relying on GC to promptly
collect
it?
Apparently somehow these objects can survive the automatic
collections...disposing it would help. Thanks for your comment
and
help.

internal class CMyClass
{
ArrayList m_array = new ArrayList( 50000 );
private string m_idStr;
private Guid m_guid;
internal CMyClass( int n )
{
for( int i = 0; i < n; ++i )
m_array.Add( Guid.NewGuid() );

m_guid = Guid.NewGuid();
m_idStr = m_guid.ToString();
}

internal Guid id
{
get{ return (Guid ) m_array[ 0 ]; }
}

~CMyClass()
{
// Trace.Write( m_guid, m_idStr );
}

}
private void RunBtn_Click(object sender,

System.EventArgs
e)

{
ResultEd.Text = "";
try
{

for( int i = 0; i < int.Parse( NumberEd.Text );
++i )
{

Hashtable table = new Hashtable( 100 );
ArrayList ids = new ArrayList( 10 );
for( int j = 0; j < 10; ++j )
{
Guid id = Guid.NewGuid();
table[ id ] = null;
ids.Add( id );
}


for( int k=0; k < 10; ++k )
{
foreach( Guid id in ids )
{
table[ id ] = new CMyClass( 10 );
}

CMyClass myobj;
foreach( Guid id in ids )
{
myobj = (CMyClass) table[ id ];
myobj.id.ToString();
}
} // for k
} // for
}
catch( Exception ex )
{
ResultEd.Text = ex.Message + "...CallSTack:" +
ex.StackTrace;
}

GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();

GC.WaitForPendingFinalizers();
GC.Collect();

ResultEd.Text = "Done";
}

 

[Zeng]

That's strange, not too long ago Willy sounded so knowledgable about this
subject and almost like a salesman, now I haven't heard anything from him.
From this I can conclude:

1) Somehow Willy wouldn't dare to admit the truth that GC design and/or
implementation is messed up in this aspect. Hope he's not one of those
"bright" guys that Jon Shemitz referred to as responsible for GC
design/implementation.
2) GC is not releasing unused memory promptly and occasionally it is the
main cause for the process to get shutdown and recycled
2) GC is messing up another one. In the past I also found that that the LOH
(large object heap) gets fragmented gradually and the gap in between each
useful blocks might not ever get to be useful until the whole process gets
recycled (shutdown) because the total amount of used memory reaching max%.
The reason is GC never spends cpu cycles to compact it even before the
process recycles itself.
3) GC.Collect() has no useful purpose other than for decoration (marketing)
because calling it is bad - no one should ever call it, calling it doesn't
do what the name "Collect" suggests anyway. There is no reason for any app
to call it.

I'm asking you the same question as I have asked BillR:

Is it possible for my process to get recycled because it reaches memory
max% even though most of the memory counted as used is no longer needed by
my app and it is not freed because GC hasn't gotten a chance to do so
safely? If that's true, sounds to me that having a finalizer in my class or
not would only *reduce* the chance of that occuring, but not *eliminate*, is
that accessment accurate to you?

By the way, I hope I don't need to correct all my mis-understanding what the
GC is meant for to raise that question.

Seems like you have a fundamental mis-understanding on what the GC is meant
for and how it's actually performing.
The GC's task is, to collect the memory space occupied by non-reachable
objects and compact the generation it is actually collecting, so that a
contiguous free space remains in the heap to add new objects.
A full GC is a GC run that collects all generations, the current version of
the CLR has 3 generational logical heaps plus a separate large object heap
(LOH), from code you can ask for a GC run by calling GC.Collect(n) where n
indicates the generation to end with, a collection always starts with
generation 0.
GC.Collect() collects all generations plus the LOH, that's why it's

called

a
full collect.

However, it's NOT the task of the GC to bring down the heap size, that's the
task of the CLR memory manager , or the hosting process memory manager (if
any) in close cooperation with the OS.

Your code sample needs at least two GC.Collect() calls, that's because you
have a Finalizer (destructor in C# parlance).
When an instance of a finalizable object gets instantiated, it's registered
as finalizable.
When it is no longer rooted at the next GC run, it will be moved to the
finalizable queue, where it stays until after the finalizer has run, after
which it's removed from the finalizer queue and it becomes eligible for
collection.
Note that it's possible that not all finalizables are immediately finalized,
all depends on the load of the system and the time the finalizer thread
spends finalizing objects. The finalizer thread can be suspended before all
finalizer have run, that's why we say at LEAST 2 GC runs, and why we suggest
against destructors in C#.

Willy.

PS I suggest you start reading these (somewhat outdated) articles , before
you start arguing about a subject you don't seem to fully understand.
http://msdn.microsoft.com/msdnmag/issues/1100/GCI/default.aspx
http://msdn.microsoft.com/msdnmag/issues/1200/GCI2/default.aspx

exposed

so

decide

to

safe

GC

MemoryLimit%

it

memoryLimit="60"

as

them

on

(which

is

very
very smart most of the time)

By the way, where can I find a documentation about the safe-points?
Wouldn't that be better that there is a call to wait for the system
to
be
done with collection and there is a safe point in that method? And
is
there
a safe point in the component that checks for memory usage and
recycle
the
aspnet process when 60%(default) is reached?



and just to add my two pennies worth ...

Although you may call GC.Collect(), much the same as in Java when
you
try
to
force the VM to run garbage collection, it will still run at it's
earliest
convenience.

During compilation, your code is injected with "safe points"
whereby
the
GC
can hijack the thread and take control to do its work. Now, when
you
call
GC.Collect() your code might not be in a stable enough state for
the
GC
to
run, and the only way that the GC can know that it is safe to run
is
if
it
has reached a "safe point".

Generally speaking, it is bad practice to call GC.Collect() since
you
will
inadvertantly interrupt a perfectly (or near to) working system,
and
you
yourself can cause all sorts of naughtiness to occur.

My choice of preference (as it is for a lot of developers) is to
implement
IDisposable.

AND, yes, our code should be easily readable and left in a state
that
renders it possible for future devlopers to look at it and see what
is
going
on (for maintenance reasons, or whatever), however, designing our
classes
"off centre" just in case, the next developer doesn't know as much
as
us
is a
pretty poor choice IMHO.

--
Of all words of tongue and pen, the saddest are: "It might have
been"

Bill.Richards @ greyskin .co .uk
http://greyskin.co.uk


:


I finally narrowed down my code to this situation, quite a few
(not
all)
of
my CMyClass objects got hold up after each run of this function
via
the
simple webpage that shows NumberEd editbox. My memory profile
shows
that
those instances survive 3 rounds of GC collections - it's not
what
I
expected. In my real code, CMyClass occupies big amount of
memory
and
they
all share one stance of another class that I don't have enough
memory
hold
more than a just a few in the memory. Notice that the
finalizaer
the
my
CMyClass makes a big difference in demonstrating this issue, w/o
it
the
problem doesn't exist. The interesting thing is if I run the
page
again,
the old dangling ones got destroyed and the new ones become
dangling.
Am
I
missing something about the GC? Do I need to explicitly implement
and
call
dispose for these classes instead of relying on GC to promptly
collect
it?
Apparently somehow these objects can survive the automatic
collections...disposing it would help. Thanks for your comment
and
help.

internal class CMyClass
{
ArrayList m_array = new ArrayList( 50000 );
private string m_idStr;
private Guid m_guid;
internal CMyClass( int n )
{
for( int i = 0; i < n; ++i )
m_array.Add( Guid.NewGuid() );

m_guid = Guid.NewGuid();
m_idStr = m_guid.ToString();
}

internal Guid id
{
get{ return (Guid ) m_array[ 0 ]; }
}

~CMyClass()
{
// Trace.Write( m_guid, m_idStr );
}

}
private void RunBtn_Click(object sender, System.EventArgs
e)
{
ResultEd.Text = "";
try
{

for( int i = 0; i < int.Parse( NumberEd.Text );
++i )
{

Hashtable table = new Hashtable( 100 );
ArrayList ids = new ArrayList( 10 );
for( int j = 0; j < 10; ++j )
{
Guid id = Guid.NewGuid();
table[ id ] = null;
ids.Add( id );
}


for( int k=0; k < 10; ++k )
{
foreach( Guid id in ids )
{
table[ id ] = new CMyClass( 10 );
}

CMyClass myobj;
foreach( Guid id in ids )
{
myobj = (CMyClass) table[ id ];
myobj.id.ToString();
}
} // for k
} // for
}
catch( Exception ex )
{
ResultEd.Text = ex.Message + "...CallSTack:" +
ex.StackTrace;
}

GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();

GC.WaitForPendingFinalizers();
GC.Collect();

ResultEd.Text = "Done";
}