@Override
    public Call<List<Span>> map(List<String> input) {
      if (input.isEmpty()) return Call.emptyList();

      SearchRequest getTraces = SearchRequest.create(indices).terms("traceId", input);
      return search.newCall(getTraces, BodyConverters.SPANS);
    }
To not produce unnecessarily long queries, we don't look back further than first ES support
zipkin-storage/elasticsearch/src/main/java/zipkin2/elasticsearch/ElasticsearchSpanStore.java