es分页查询 - 技术栈

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：

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。
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

java 复制代码

    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io
            sourceBuilder.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;
    }