Intermittent 'Out of memory' error

[Liverpool fan]

I have a VB .NET windows application that is throwing an intermittent
'out of memory' error. Here is the call stack.

Out of memory.

at System.Drawing.Graphics.FromHdcInternal(IntPtr hdc)
at System.Windows.Forms.DibGraphicsBufferManager.Crea teBuffer(IntPtr
src, Int32 offsetX, Int32 offsetY, Int32 width, Int32 height)
at
System.Windows.Forms.DibGraphicsBufferManager.Allo cBuffer(Graphics
targetGraphics, IntPtr targetDC, Rectangle targetBounds)
at System.Windows.Forms.DibGraphicsBufferManager.Allo cBuffer(IntPtr
target, Rectangle targetBounds)
at System.Windows.Forms.Control.WmPaint(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.ControlNativeWindow.OnMessage (Message& m)
at System.Windows.Forms.ControlNativeWindow.WndProc(M essage& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32
msg, IntPtr wparam, IntPtr lparam) Source = System.Drawing

The program uses our own timer form that gives a countdown between each
processing cycle. Each processing cycle looks for reports that need
running from 3 SQL Server 2000 databases (don't ask why there are
three). Also, once a day it does a bcp load of data into each of the 3
database and runs various snapshot tasks.

I don't think the details are important besides to say it is doing a
fair amount of processing.

The question is, is this likely to be caused by memory leakage. Sounds
like it to me but I thought that I'd find out if anybody else gets this
error. The call stack is always the same but it fails at various times
of day but sometimes not for 2 weeks.

I have been monitoring the memory usage and it does go up gradually
over time from 120Mb to 150Mb. I have added garbage collection calls to
no effect.

The program uses COM in various places.

Any advice greatly appreciated.

[Cor Ligthert [MVP]]

Liverpool fan,

Have a look about all that is written about dispose on MSDN to clean up your
not managed resources.

http://msdn.microsoft.com/library/de...posemethod.asp

http://msdn.microsoft.com/library/de...izeDispose.asp

Using the dispose methods implemented in the managed classes will probably
not help you as well as calling the gc for the same,

I hope this helps,

Cor
"Liverpool fan" <ch*********@feltex.comschreef in bericht
news:11*********************@m73g2000cwd.googlegro ups.com...

>I have a VB .NET windows application that is throwing an intermittent
'out of memory' error. Here is the call stack.

Out of memory.

at System.Drawing.Graphics.FromHdcInternal(IntPtr hdc)
at System.Windows.Forms.DibGraphicsBufferManager.Crea teBuffer(IntPtr
src, Int32 offsetX, Int32 offsetY, Int32 width, Int32 height)
at
System.Windows.Forms.DibGraphicsBufferManager.Allo cBuffer(Graphics
targetGraphics, IntPtr targetDC, Rectangle targetBounds)
at System.Windows.Forms.DibGraphicsBufferManager.Allo cBuffer(IntPtr
target, Rectangle targetBounds)
at System.Windows.Forms.Control.WmPaint(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.ControlNativeWindow.OnMessage (Message& m)
at System.Windows.Forms.ControlNativeWindow.WndProc(M essage& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32
msg, IntPtr wparam, IntPtr lparam) Source = System.Drawing

The program uses our own timer form that gives a countdown between each
processing cycle. Each processing cycle looks for reports that need
running from 3 SQL Server 2000 databases (don't ask why there are
three). Also, once a day it does a bcp load of data into each of the 3
database and runs various snapshot tasks.

I don't think the details are important besides to say it is doing a
fair amount of processing.

The question is, is this likely to be caused by memory leakage. Sounds
like it to me but I thought that I'd find out if anybody else gets this
error. The call stack is always the same but it fails at various times
of day but sometimes not for 2 weeks.

I have been monitoring the memory usage and it does go up gradually
over time from 120Mb to 150Mb. I have added garbage collection calls to
no effect.

The program uses COM in various places.

Any advice greatly appreciated.

[Liverpool fan]

Thanks for replying Cor. I has already tried enforcing a Garbage
Collection which seemed to help to an extent but only to decrease the
frequency of the error. I'll have a look at the articles and compare to
what I am doing already as far as COM is concerned.

Here is the Timer calling routine. I have changed it slightly in that
instead of creating a new timer dialog for each loop, I reuse the
previous one. This seems to have helped immensely but I now have a 4K
creeping of memory usage for each loop (when nothing is executed).

Private Sub StartTimer()

Dim dtloadfull, dtjobscan As Date
Dim sLoadFull As String = "Load Sales Extract"
Dim sprocessjobs As String = "Process Job Queue"

Me.ListBox1.Items.Add("Started " & Date.Now.ToString)
Me.ListBox1.SelectedIndex = Me.ListBox1.Items.Count - 1

' next order scan
dtjobscan = DateAdd(DateInterval.Minute, myJobScanInterval,
Now)

' launch the timer
f = New dlgZTimer
f.TimerIntervalSecs = 1

Do
'Clean up memory
GC.Collect

' get time of next full update. may be next day.
If myFullLoadTime = "" Then
dtloadfull = Nothing
Else
dtloadfull =
System.Convert.ToDateTime(Now.ToShortDateString & " " & myFullLoadTime)
Do While dtloadfull < Now
dtloadfull = DateAdd(DateInterval.Day, 1,
dtloadfull)
Loop
Me.lblProgress.Text = "Progress (" & "Next full
extract load at " & dtloadfull.ToString & ")"
Application.DoEvents()
End If

' next order scan
dtjobscan = DateAdd(DateInterval.Minute, myJobScanInterval,
Now)

f.TimerTitle = ""

If myFullLoadTime = "" Then
f.TimerTitle = sprocessjobs
f.TargetTime = dtjobscan
Else
' if full load is in the next 10 minutes, wait for it
If dtloadfull <= DateAdd(DateInterval.Minute, 10, Now)
Then
f.TimerTitle = sLoadFull
f.TargetTime = dtloadfull
Else
' no trans available, check for orders
f.TimerTitle = sprocessjobs
f.TargetTime = dtjobscan
End If
End If

If f.TimerTitle <"" Then

If f.ShowDialog(Me) = DialogResult.OK Then
If f.TimerTitle = sprocessjobs Then

If myMultiThreaded = True Then
ProcessJobQueueMultiThreaded()
Else
ProcessJobQueue()
End If
' test for network connection
If myLastNetworkCheck < Now.AddHours(-1) Then
Try
DisplayHistory("******** Testing
network connection")
Dim str As String()
str =
System.IO.Directory.GetFiles(myBCP_Full_Directory)
myLastNetworkCheck = Now
Catch ex As Exception
DisplayErrorInList(ex)
End Try
End If

End If

If f.TimerTitle = sLoadFull Then
ProcessEOD()

' test to see if EOD data has been loaded
CheckEODStatus()
End If
Else
' Cancelled
f.Dispose()
f = Nothing
Exit Sub
End If
End If
Loop

End Sub

I have focussed on this because of the rate that the memory was being
used up even when the program wasn't doing anything but running the
timer. Seemed to be a prime candidate.

Any thoughts greatly appreciated.