es分页查询

ES（Elasticsearch）分页查询通常使用 from 和 size 参数来控制查询结果的分页。from 用于指定从哪个结果开始，size 用于指定返回多少条记录。

示例查询

假设你想查询 my_index 索引，并且希望分页获取数据：

json

GET /my_index/_search { "from": 0, "size": 10, "query": { "match_all": {} } }

参数解释：

• from: 表示从第几条记录开始（默认为0，表示从第一条开始）。
• size: 表示每页返回多少条记录。

分页逻辑：

• 第一页：from = 0, size = 10（返回从0到9的记录）。
• 第二页：from = 10, size = 10（返回从10到19的记录）。
• 第三页：from = 20, size = 10（返回从20到29的记录）。

注意事项：

1. 当你分页查询时，如果数据量非常大，建议使用search_after进行深分页，它比from/size更高效。
2. from 和 size 使用时会增加查询的开销，特别是在大数据集上。

from size

    public List<ResFoodOrderInspectionVO> queryGroupByOrgGroupLocationCode(ReqFoodOrderInspectionVO reqVO) {log.info("食用订单巡检表查询条件：{}", reqVO.toString());StopWatch stopwatch = new StopWatch();stopwatch.start();List<ResFoodOrderInspectionVO> resList = Lists.newArrayList();SearchRequest searchRequest = new SearchRequest(EsOperateTables.FOOD_ORDER_INSPECTION_V2.getAlias());SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();searchSourceBuilder.fetchSource(RES_FBASEFOODORDERINSPEC_FIELDS, null);
//        searchSourceBuilder.size(0);// 设置为0代表不需要取查询到的所有数据，只需要取聚合的相关的数据searchSourceBuilder.size(reqVO.getSize());searchSourceBuilder.from((reqVO.getPage() - 1) * reqVO.getSize());BoolQueryBuilder booleanQuery = QueryBuilders.boolQuery();// 组装查询条件buildBooleanQuery(booleanQuery, reqVO);searchSourceBuilder.query(QueryBuilders.constantScoreQuery(booleanQuery));// 分组，统计，排序FoodOrderInspectionConvertor.groupCountAgg(searchSourceBuilder, reqVO, foodOrderInspectionDisabled);searchRequest.source(searchSourceBuilder);SearchResponse searchResponse = null;try {searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);stopwatch.stop();} catch (IOException e) {log.error(ErrorMsgConstant.FOODORDERINSPECTION_QUERYES_ERROR, e);throw new OrderCenterException(ErrorMsgConstant.FOODORDERINSPECTION_QUERYES_ERROR);}if (Objects.isNull(searchResponse)) {return Collections.emptyList();}Terms terms = searchResponse.getAggregations().get(FoodOrderInspectionConstant.GROUPDIMENSION);if (Objects.isNull(terms)) {return Collections.emptyList();}// 包含门店，且按日统计时，需要判断总量，其他场景，总分组量实际不会大于10000，不需要判断if (CollectionUtils.isNotEmpty(reqVO.getLocationCodes()) && !reqVO.getGroupMonth() && searchResponse.getHits().getTotalHits() > FoodOrderInspectionConstant.GROUP_RETURN_SIZE) {throw new OrderCenterException(ErrorMsgConstant.GROUP_TOTALSIZE_TOOLONG);}// 组装数据for (Terms.Bucket entry : terms.getBuckets()) {resList.add(FoodOrderInspectionConvertor.toResVO(entry, reqVO));}// 取聚合统计后合计Map<String, Aggregation> totalMap = searchResponse.getAggregations().getAsMap();resList.forEach(v -> {v.setResFoodOrderInspectionTotalVO(FoodOrderInspectionConvertor.buildTotal(totalMap));});log.info("食用订单巡检报表查询耗时:{}", stopwatch.getTotalTimeMillis());return resList;}}

searchAfter

    private SearchRequest buildSearchRequest(EsSchemel esSchemel, QueryBuilder params, int pageSize, String orderBy, String scrollId) {if (pageSize > 10000) {//fixed:es error，from + size must be less than or equal to: [10000]pageSize = 10000;}SearchRequest searchRequest = new SearchRequest(esSchemel.getIndex());searchRequest.types(esSchemel.getType());SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();sourceBuilder.query(params);//sourceBuilder.from(pageNo - 1);sourceBuilder.size(pageSize);sourceBuilder.timeout(new TimeValue(30, TimeUnit.SECONDS));if (esSchemel.getSelectCols() != null && esSchemel.getSelectCols().length > 0) {//性能参数，减少iosourceBuilder.fetchSource(esSchemel.getSelectCols(), EXCLUDEFIELDS);}if (!Strings.isNullOrEmpty(orderBy)) {sourceBuilder.sort(new FieldSortBuilder(orderBy).order(SortOrder.DESC));if (!Strings.isNullOrEmpty(scrollId)) {sourceBuilder.searchAfter(new Object[]{scrollId});}}searchRequest.source(sourceBuilder);return searchRequest;}