private boolean containsAllFieldNames(Fields fields) {
            if (this.properties.size() < fields.properties.size()) {
                return false;
            }
            return this.properties.keySet().containsAll(fields.properties.keySet());
        }
Returns ture when the input fields have already been stored in the properties.
oap-server/server-storage-plugin/storage-elasticsearch-plugin/src/main/java/org/apache/skywalking/oap/server/storage/plugin/elasticsearch/base/IndexStructures.java