我有超过100个索引在弹性。我想返回所有索引的所有唯一值。

String[] instanceNames = getAllIndices().toArray(String[]::new);
    Map<String, Map<String, Set<String>>> results = new HashMap<>();

    for (String element : instanceNames) {

        SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices(element);
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        searchSourceBuilder.query(QueryBuilders.matchAllQuery);
        searchSourceBuilder.aggregation(AggregationBuilders.terms("DISTINCT_VALUES").field("provider.keyword"));
        searchRequest.source(searchSourceBuilder);
        SearchResponse searchResponse = null;
        try {
            searchResponse = getClient().search(searchRequest, RequestOptions.DEFAULT);
        } catch (ElasticsearchException | IOException e) {
            throw new ServiceException(I18n.ELASTIC_SEARCH_ERROR, e);
        }

        List<SearchHit> searchHits = Arrays.asList(searchResponse.getHits().getHits());
        }

instanceNames -〉包含了我的elasticsearch中的所有索引。这个方法可以工作，但是返回数据非常慢。