AcadMap object data access leads to memory leak?

This post is for those who do VBA in AcadMAP to manipulate object data.

Situation:

I am doing a VBA work that retrieving AcadMap object data into
database/file. I have done similar things several times. Only this time
there is a lot more object data to be extracted: about 40,000 polygons with
object data attached, these object data belongs to 10 object data tables and
each table has up to 40 fields.

No problem for me to write code to loop through each polygon and each map
object data table to retrieve all object data values and then save to
database/file.

The problem is that if object data attached to a polygon is accessed for
retrieving, the computer memory usage increases and the program crashes
eventually before the processing is done (I have pretty good computer: P4
3.4 MHz + 1G memory, AutoCAD Map5 - 2002). The task manager indicates near
3G memory (1G memory + near 2G virtual memory) was used at crash point.

The code (and see my comments between code):

Option Explicit

Public Sub MapObjectData_Extract_Test()

Dim aMap As AutocadMAP.AcadMap
Dim mProj As AutocadMAP.Project

Set aMap =
ThisDrawing.Application.GetInterfaceObject("AutoCADMap.Application")
Set mProj = aMap.Projects(ThisDrawing)

Dim tbl As ODTable
For Each tbl In mProj.ODTables
ExtractMapData tbl ''' Here to extract object data under each
object data table
If MsgBox(tbl.Name & " is done." & vbCr & vbCr & _
"Do you want to continue?", vbYesNo) = vbNo Then Exit For
DoEvents ''Ensure that I can stop the long looping by clicking STOP
button in VBA
Next

End Sub

Private Sub ExtractMapData(tbl As ODTable)

Dim ent As AcadEntity

'' loop through each entity
For Each ent In ThisDrawing.ModelSpace
If Typeof ent Is AcadLWPolyline Then GetObjectData ent, tbl
Next

End Sub

Private Sub GetObjectData(ent As AcadEntity, tbl As AutocadMAP.ODTable)

Dim records As ODRecords
Dim var As Variant

Set records = tbl.GetODRecords()

If records.Init(ent, False, True) Then

Do Until records.IsDone

''Get data filed by field and save to file/database

''' If I comment out folowing lines of code, the memory usage
during processing changes a bit, by increasing 5 to 10 MB
''' if these lines of code were executed, memory usage increases
quickly, leading to crash.
''' it seems, if I access object data by using
records.Record.Item(index), the object data were get into memory to be
pointed to
''' but is not released, even var is the only variable
referenced to it and goes out scope

''' var = records.record.Item(0).Value
''' var = records.record.Item(1).Value
''' var = records.record.Item(2).Value
''' var = records.record.Item(3).Value
''' var = records.record.Item(4).Value
''' var = records.record.Item(5).Value
''' var = records.record.Item(6).Value
''' var = records.record.Item(7).Value
''' var = records.record.Item(8).Value
''' .....
''' var = records.record.Item(40).Value

records.Next

Loop

End If

Set records=Nothing ''' Not necessary, but no harm and does not solve
the problem

End Sub


Does anyone have similar problem?

Previusly, I had trouble with ODRecords.Reocrd.Item(index).Value. for
example, when you set a object data filed value of text type:

Dim strValue as string 'strValue should be ""
records.Record.Item(index).Value=strValue ''' Crashes!!!

if yo do

Dim strValue as string
strValue=""
records.Record.Item(index)=strValue ''' OK!!!, you just expliciltly
assign strValue to "",
''' while we
all know VB/VBA make "" as default string value when string variable is
declared

This example may indicate some weired COM interface impliment of AcadMAP
object data. I hope someone could point out it is my mistake that causes the
serious memory leak