Call a PostgreSQL function with parameters via VBA - vba

Question

Why do I get an error that my object is closed in the line Range("A1").CopyFromRecordset rcs?
Sub NamenAusBenutzerCmd_SO()
Dim cmd As New ADODB.Command
Dim rcs As New ADODB.Recordset
With cmd
.ActiveConnection = cnn
.CommandText = "myschema.myfunction"
.CommandType = adCmdStoredProc
.Parameters("myparameter").Value = "xyz"
Set rcs = .Execute()
Range("A1").CopyFromRecordset rcs
End With
End Sub
The connection is fine, the recordset executes but then I get the error 3704, the process is not permitted for a closed object.
By the way: The function itself runs directly in pgAdmin, so it´s ok.
And when I try Debug.Print rcs.Fields("myfunction").Value instead of the bold line above I get the error 3265, that an object with this name cannot be finded.
I watched YouTube videos, asked google and found exact the same way. I don´t see my mistake :-/
Sorry, I edit my question from here, because there is another thing I would like to ask you. I hope to increase the performance with the command. Instead of open and close a recordset 100 times in a loop like here:
With rcs
For i = 1 To 100
myparameter = Cells(i, 1).Value
.Open ("SELECT myschema.myfunction('" & myparameter & "')"), cnn, adOpenForwardOnly, adLockReadOnly
Cells(i, 2).Value = .Fields("myfunction").Value
.Close
Next i
End With
i hope to do it faster even with the command. I still don´t know why the way with .CommandType = adCmdStoredProc doesn´t run, but it runs this way:
With cmd
.ActiveConnection = cnn
For i = 1 To 100
myparameter = Cells(i, 1).Value
.CommandText = "SELECT myschema.myfunction('" & myparameter & "')"
.CommandType = adCmdText
Set rcs= .Execute
Cells(i, 2).Value = rcs.Fields("myfunction").Value
Next i
End With
But the performance is as bad as with the open-close-rcs.
So maybe I try to solve a thing which will not help me?