NodeTupleTable ntt = ds.getQuadTable().getNodeTupleTable() ;
// Don't worry about abortable - this iterator should be fast
// (with normal indexing - at least one G???).
// Either it finds a starting point, or it doesn't. We are only
// interested in the first .hasNext.
Iterator<Tuple<NodeId>> iter1 = ntt.find(nid, NodeId.NodeIdAny, NodeId.NodeIdAny, NodeId.NodeIdAny) ;
if ( filter != null )
iter1 = Iter.filter(iter1, filter) ;
exists = iter1.hasNext() ;
}