public boolean containsFieldNames(String tableName, Mappings mappings) {
        if (Objects.isNull(mappings) ||
            CollectionUtils.isEmpty(mappings.getProperties())) {
            return true;
        }

        return mappingStructures.containsKey(tableName) &&
                mappingStructures.get(tableName)
                        .containsAllFieldNames(new Fields(mappings));
    }
Check whether all the fields are already defined regardless of the field types.
When OAP runs in no-init mode, it doesn't care about the field types, it just
cares about whether the data can be ingested without reporting error.
OAP running in init mode should take care of the field types.
oap-server/server-storage-plugin/storage-elasticsearch-plugin/src/main/java/org/apache/skywalking/oap/server/storage/plugin/elasticsearch/base/IndexStructures.java