private boolean shouldBeDegraded(Query query, IndexFacts.Session indexFacts) {
        if (query.getRanking().getSorting() == null) return false;
        if (query.getRanking().getSorting().fieldOrders().isEmpty()) return false;
        if ( ! query.getSelect().getGrouping().isEmpty()) return false;
        if ( ! query.properties().getBoolean(DEGRADING, true)) return false;

        Index index = indexFacts.getIndex(query.getRanking().getSorting().fieldOrders().get(0).getFieldName());
        if (index == null) return false;
        if ( ! index.isFastSearch()) return false;
        if ( ! index.isNumerical()) return false;
        if ( index.isMultivalue()) return false;

        return true;
    }
Set this to false in query.properties to turn off degrading. Default: on
container-search/src/main/java/com/yahoo/search/querytransform/SortingDegrader.java