private long GetIdPosition(NeoDatis.Odb.OID oid)
 {
     // first check if it is the last
     if (lastIds[lastIdIndex] != null && lastIds[lastIdIndex].Equals(oid))
     {
         return(lastIdPositions[(lastIdIndex)]);
     }
     for (int i = 0; i < IdBufferSize; i++)
     {
         if (lastIds[i] != null && lastIds[i].Equals(oid))
         {
             return(lastIdPositions[i]);
         }
     }
     // object id is not is cache
     return(objectReader.ReadOidPosition(oid));
 }