最近在用es做统计的时候，有个同比和环比的需求，但是数据量超过10000的时候只能显示10000+，如下：

image.png

经过在网上冲浪之后找到了解决办法，一行代码搞定！

searchSourceBuilder.trackTotalHits(true);

官网解释是这样的：

image.png

elasticsearch 分页查询全部数据只显示10000条问题

当索引非常非常大(千万或亿)，是无法安装 from + size 做深分页的，分页越深则越容易OOM，即便不OOM，也是很消耗CPU和内存资源的。官方在后2.x版本中已增加限定 index.max_result_window:10000作为保护措施 ，即默认 from + size 不能超过1万。

所以数据量大的话，采用scroll游标查询。

        final Scroll scroll = new Scroll(TimeValue.timeValueMinutes(1L)); //设定滚动时间间隔
        searchRequest.scroll(scroll);
        searchSourceBuilder.size(1000); //设定每次返回多少条数据

        searchRequest.source(searchSourceBuilder);
        SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);

        String scrollId = searchResponse.getScrollId();
        List<Map<String, Object>> mapList = new ArrayList<>();
        boolean flag;
        SearchHit[] searchHits = searchResponse.getHits().getHits();
        for (SearchHit searchHit : searchHits) {
                mapList.add(searchHit.getSourceAsMap());
            }
        }

        //遍历搜索命中的数据，直到没有数据
        while (searchHits != null && searchHits.length > 0) {
            SearchScrollRequest scrollRequest = new SearchScrollRequest(scrollId);
            scrollRequest.scroll(scroll);
            try {
                searchResponse = restHighLevelClient.scroll(scrollRequest, RequestOptions.DEFAULT);
            } catch (IOException e) {
                e.printStackTrace();
            }
            scrollId = searchResponse.getScrollId();
            searchHits = searchResponse.getHits().getHits();
            if (searchHits != null && searchHits.length > 0) {
                for (SearchHit searchHit : searchHits) {
                        mapList.add(searchHit.getSourceAsMap());
                    }
                }
            }
        }
        //清除滚屏
        ClearScrollRequest clearScrollRequest = new ClearScrollRequest();
        clearScrollRequest.addScrollId(scrollId);//也可以选择setScrollIds()将多个scrollId一起使用
        ClearScrollResponse clearScrollResponse = null;
        try {
            clearScrollResponse = restHighLevelClient.clearScroll(clearScrollRequest,RequestOptions.DEFAULT);
        } catch (IOException e) {
            e.printStackTrace();
        }
        boolean succeeded = clearScrollResponse.isSucceeded();
        System.out.println("succeeded:" + succeeded);