public static String uniqueFunctionName(final Class<?> aClass) {
        Annotation annotation = doGetAnnotation(aClass, MeterFunction.class);
        if (annotation != null) {
            return (METER.getName() + Const.LINE + ((MeterFunction) annotation).functionName()).toLowerCase();
        }
        annotation = doGetAnnotation(aClass, MetricsFunction.class);
        if (annotation != null) {
            return (METRICS.getName() + Const.LINE + ((MetricsFunction) annotation).functionName()).toLowerCase();
        }
        return "";
    }
The unique function name pattern is {function category}-{function name}.
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/analysis/FunctionCategory.java