why are the ES_peony_new_index_indexing_slowlog.log and ES_peony_new_index_search_slowlog.log both empty?

Hi,
I don't understand why the ES_peony_new_index_indexing_slowlog.log and ES_peony_new_index_search_slowlog.log are both empty, is there something need to configure in the elasticsearch.yml file? I want to look up the search log when I make query test, can someone help, please?