@Override
    protected StorageID id0() {
        String id;
        if (layer != null) {
            id = encode(name) + Const.POINT + layer.value();
        } else {
            id = encode(name) + Const.POINT + Layer.UNDEFINED.value();
        }
        return new StorageID().appendMutant(new String[] {
            NAME,
            LAYER
        }, id);

    }
Primary key(id), to identify a service with different layers, a service could have more than one layer and be
saved as different records.

@return Base64 encode(serviceName) + "." + layer.value
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/analysis/manual/service/ServiceTraffic.java