private static int documentSelectionQueryParameterCount(Query query) {
        int paramCount = 0;
        if (query.properties().getString(streamingUserid) != null)
            paramCount++;
        if (query.properties().getString(streamingGroupname) != null)
            paramCount++;
        if (query.properties().getString(streamingSelection) != null)
            paramCount++;
        return paramCount;
    }
The route to the storage cluster.
container-search/src/main/java/com/yahoo/vespa/streamingvisitors/StreamingBackend.java