MapServer 4.10.1 Memory Leak still exists

[David Martin]

I have been testing MS 4.10.0 and 4.10.1 and have found that the Memory 
Leak issue identifed in 4.10.0 still exists in 4.10.1 when running the C# 
mapserver dlls and Mapscript.

Now I am using vb.net for the code development. I have released the code 
live today and found it ran for 30mins before it consumed over 1Gb of system 
memory. The code I am using is as follows:

There are two subs that inerface to MS one to display images and the other 
to process form data and run a query:

    Private Sub DisplayImage(ByVal RefineImage As Boolean)
        Dim imageLoc, RefimageLoc As String
        If RefineImage Then
            ' This is a refined query - show number of results to the screen and 
also the refined map
            imageLoc = "/Uploads/iMapPlot/tmp/" & Math.Abs(Now.ToBinary) 
& ".gif"
            RefimageLoc = "/Uploads/iMapPlot/tmp/Ref" & Math.Abs
(Now.ToBinary) & ".gif"
            MSMap = New mapObj(MapFile())
            MSMap.setExtent(CurrentExtent.minx, CurrentExtent.miny, 
CurrentExtent.maxx, CurrentExtent.maxy)
            Dim Refineimg As imageObj
            Dim Referenceimg As imageObj
            If MapLayers <> "" Then
                Dim layerElements As String() = Split(MapLayers, ",")
                Dim layer As String
                Dim lyr As layerObj
                For Each layer In layerElements
                    lyr = MSMap.getLayerByName(layer)
                    lyr.status = STATUS_VALUES.MS_ON
                    If layer = "Places" Then
                        lyr.data = "..\ExplorOz\Places\" & PlacesPOIName
                        Dim sty As styleObj = lyr.getClass(0).getStyle(0)
                        sty.setSymbolByName
(MSMap, "../../Images/PointPlace/symbols/" & PlacesPOIImage & ".gif")
                    End If
                Next
            End If
            Refineimg = MSMap.draw
            Refineimg.save(Server.MapPath(imageLoc), Nothing)
            Refineimg.Dispose()
            Referenceimg = MSMap.drawReferenceMap
            Referenceimg.save(Server.MapPath(RefimageLoc), Nothing)
            Referenceimg.Dispose()
            CurrentExtent.maxx = MSMap.extent.maxx
            CurrentExtent.minx = MSMap.extent.minx
            CurrentExtent.maxy = MSMap.extent.maxy
            CurrentExtent.miny = MSMap.extent.miny
            MSMap.Dispose()
            MainMap.Src = imageLoc
            refimg.Src = RefimageLoc
        Else
            imageLoc = "/Uploads/iMapPlot/Cache/" & Replace(Mid(MapFile, 
InStrRev(MapFile, "\") + 1), ".map", "_" & Replace(MapLayers, ",", "") & 
PlacesPOIName & ".gif")
            RefimageLoc = "/Uploads/iMapPlot/Cache/Ref" & Replace(Mid(MapFile, 
InStrRev(MapFile, "\") + 1), ".map", "_" & Replace(MapLayers, ",", "") & 
PlacesPOIName & ".gif")
            If Not System.IO.File.Exists(Server.MapPath(imageLoc)) Or Not 
System.IO.File.Exists(Server.MapPath(RefimageLoc)) Then
                Dim img As imageObj
                Dim Referenceimg As imageObj
                MSMap = New mapObj(MapFile())
                If MapLayers <> "" Then
                    Dim layerElements As String() = Split(MapLayers, ",")
                    Dim layer As String
                    Dim lyr As layerObj
                    For Each layer In layerElements
                        lyr = MSMap.getLayerByName(layer)
                        lyr.status = STATUS_VALUES.MS_ON
                        If layer = "Places" Then
                            lyr.data = "..\ExplorOz\Places\" & PlacesPOIName
                            Dim sty As styleObj = lyr.getClass(0).getStyle(0)
                            sty.setSymbolByName
(MSMap, "../../Images/PointPlace/symbols/" & PlacesPOIImage & ".gif")
                        End If
                    Next
                End If
                img = MSMap.draw
                img.save(Server.MapPath(imageLoc), Nothing)
                img.Dispose()
                Referenceimg = MSMap.drawReferenceMap
                Referenceimg.save(Server.MapPath(RefimageLoc), Nothing)
                Referenceimg.Dispose()
                MSMap.Dispose()
            End If
            MainMap.Src = imageLoc
            refimg.Src = RefimageLoc
        End If
        map.Value = MapFile()
        layer.Value = MapLayers
    End Sub

    Private Sub Query()
        Dim result As Integer
        Dim lyr As layerObj
        MSMap = New mapObj(MapFile())
        lyr = MSMap.getLayerByName(SearchLayer)
        MSMap.setExtent(CurrentExtent.minx, CurrentExtent.miny, 
CurrentExtent.maxx, CurrentExtent.maxy)
        If SearchLayer = "Places" Then lyr.data = "..\ExplorOz\Places\" & 
PlacesPOIName
        Dim s As New System.Text.StringBuilder

        result = lyr.queryByRect(MSMap, CurrentExtent)

        If result = RESULT_CODE.MS_SUCCESS Then
            Dim resCache As resultCacheObj = lyr.getResults

            If resCache.numresults > 0 Then
                Dim shp As shapeObj
                Dim fName As String
                lyr.open()
                NumResults = resCache.numresults
                For i As Integer = 0 To resCache.numresults - 1
                    shp = lyr.getFeature(resCache.getResult(i).shapeindex, 
resCache.getResult(i).tileindex)
                    For iItem As Integer = 0 To lyr.numitems - 1
                        fName = lyr.getItem(iItem)
                        If fName = "ID" Then s.Append(shp.getValue(iItem) & ",")
                    Next
                    shp.Dispose()
                Next
                If s.Length > 1 Then s.Remove(s.Length - 1, 1)
                lyr.close()
            End If

            'If SearchLayer = "Places" Then
            '    Response.Write(NumResults)
            '    Response.Write("<br />" & s.ToString)
            '    Exit Sub
            'End If
            lyr.Dispose()
            MSMap.Dispose()
End Sub

You will see that I dispose every element I create, this has been tried on two 
servers (and the production system - dual cpu, 2GB ram) - I do stress the 
application with hundreds of users per hour. The exception thrown is as 
follows:
Server Error in '/' Application.
---------------------------------------------------------------------------
-----

msLoadMap(): Memory allocation error. 
Description: An unhandled exception occurred during the execution of the 
current web request. Please review the stack trace for more information about 
the error and where it originated in the code. 

Exception Details: System.ApplicationException: msLoadMap(): Memory 
allocation error. 

[ApplicationException: msLoadMap(): Memory allocation error. ]
   mapObj..ctor(String filename) +54
   MapSearch.Query() +52
   MapSearch.Page_Load(Object sender, EventArgs e) +284
   System.Web.UI.Control.OnLoad(EventArgs e) +99
   System.Web.UI.Control.LoadRecursive() +47
   System.Web.UI.Page.ProcessRequestMain(Boolean 
includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1061


Any thoughts or help on this would be great, I have invested a heap of time 
on this interface and do not want to go back to calling the cgi system as it is 
slower - I am using the pre-compiled binaries in the MS4W package as 
downloaded two days ago.

David Martin