PRB: RDS May Return E_FAIL Status When Querying Index Server (241794)

SYMPTOMS

Using the Data Factory in Remote Data Service 2.x to query Index Server for the document titles (DocTitle field) generates one of the following errors:

The data provider or other service returned an E_FAIL status.

-or-

Error: -2147217887 (80040e21) Description: Multiple-step operation generated errors. Check each status value. Source: Microsoft Cursor Engine

-or when using MDAC 2.6 or 2.7-

Run-time error '-2147267259 (80004005)':

Stream object cannot be read because it is empty, or the current position is at the end of the stream. For non-empty streams, set the current position with the Position property. To determine if a stream is empty, check the Size property.

The same errors will result for any of the Doc* properties or user-defined properties.

CAUSE

Index Server does not hard-code the datatype for DocTitle as a string. Thus the return value is recognized as a VARIANT. Remote Data Service is known to fail when handling the DBTYPE_VARIANT datatype for a property retrieved in OLE DB. Returning such a type with Remote Data Service results in the E_FAIL status error.

MORE INFORMATION

Steps to Reproduce Behavior

Start a new Visual Basic project.
Reference Remote Data Service and ADO libraries.
Add two command buttons to Form1.

Copy and paste the following code over any declarations and code already present in the Form1 code module. Edit the server name ("HTTPServer") as appropriate.

 
Option Explicit 
Dim rs As ADODB.Recordset 
Dim strSQL As String 
Const HTTPServer As String = "myServer" 
Const Scope As String = "C:\" 
Const QueryText As String = "Index Server" 

Private Sub Command1_Click() 
    
    Dim DS As RDS.DataSpace 
    Dim DF As Object 
    
    Set DS = New RDS.DataSpace 
    Set DF = DS.CreateObject("RDSServer.DataFactory", "http://" & HTTPServer) 
    Set rs = DF.Query("Provider=msidxs", strSQL) 
    
    Do Until rs.EOF 
        Debug.Print rs("Filename"), rs("Vpath"), rs("DocTitle") 
        rs.MoveNext 
    Loop 
      
    rs.Close 
    Set rs = Nothing 
  
End Sub 

Private Sub Command2_Click() 

    Dim cn As ADODB.Connection 
    Set cn = New ADODB.Connection 
    cn.Open "Provider=MSIDXS" ';Server=http://" & HTTPServer 
    
    Set rs = cn.Execute(strSQL) 
    Do Until rs.EOF 
        Debug.Print rs("Filename"), rs("Vpath"), rs("DocTitle") 
        rs.MoveNext 
    Loop 
      
    rs.Close 
    Set rs = Nothing 
    cn.Close 
    Set cn = Nothing 
    
End Sub 

Private Sub Form_Load() 

    strSQL = "SELECT Filename, Vpath, DocTitle FROM Scope('" + Chr(34) + _ 
        Scope + Chr(34) + "') WHERE CONTAINS('" + Chr(34) + QueryText + _ 
        Chr(34) + "') > 0 ORDER BY Rank DESC" 
    Debug.Print strSQL 
    
End Sub