private static boolean stringComp(String a, String b) {
            if (Strings.isNullOrEmpty(a) && Strings.isNullOrEmpty(b)) {
                return true;
            }
            if (Strings.isNullOrEmpty(a)) {
                return false;
            }
            return a.equals(b);
        }
The parsing context holds key results more than sample collection.
oap-server/analyzer/meter-analyzer/src/main/java/org/apache/skywalking/oap/meter/analyzer/dsl/SampleFamily.java