@Override
    public final boolean combine(Metrics metrics) {
        final MinFunction minFunction = (MinFunction) metrics;
        if (this.value > minFunction.getValue()) {
            setValue(value);
        }
        return true;
    }
Service ID is required for sort query.
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/analysis/meter/function/min/MinFunction.java