ElasticSearch DateHistogram聚合填充缺失數據

Question

我試圖使用ElasticSearch春天的數據對於一些聚合

，這裏是我的查詢

final FilteredQueryBuilder filteredQuery = QueryBuilders.filteredQuery(QueryBuilders.matchAllQuery(), 
     FilterBuilders.andFilter(FilterBuilders.termFilter("gender", "F"), 
     FilterBuilders.termFilter("place", "Arizona"), 
     FilterBuilders.rangeFilter("dob").from(from).to(to))); 

final MetricsAggregationBuilder<?> aggregateArtifactcount = AggregationBuilders.sum("delivery") 
      .field("birth"); 

    final AggregationBuilder<?> dailyDateHistogarm = 
     AggregationBuilders.dateHistogram(AggregationConstants.DAILY).field("dob") 
     .interval(DateHistogram.Interval.DAY).subAggregation(aggregateArtifactcount); 

    final SearchQuery query = new NativeSearchQueryBuilder().withIndices(index).withTypes(type) 
     .withQuery(filteredQuery).addAggregation(dailyDateHistogarm).build(); 

    return elasticsearchTemplate.query(query, new DailyDeliveryAggregation()); 

而且這是我的匯聚

 public class DailyDeliveryAggregation implements ResultsExtractor<List<DailyDeliverySum>> { 

@SuppressWarnings("unchecked") 
@Override 
public List<DailyDeliverySum> extract(final SearchResponse response) { 
    final List<DailyDeliverySum> dailyDeliverySum = new ArrayList<DailyDeliverySum>(); 
    final Aggregations aggregations = response.getAggregations(); 
    final DateHistogram daily = aggregations.get(AggregationConstants.DAILY); 
    final List<DateHistogram.Bucket> buckets = (List<DateHistogram.Bucket>) daily.getBuckets(); 
    for (final DateHistogram.Bucket bucket : buckets) { 
     final Sum sum = (Sum) bucket.getAggregations().getAsMap().get("delivery"); 
     final int deliverySum = (int) sum.getValue(); 
     final int delivery = (int) bucket.getDocCount(); 
     final String dateString = bucket.getKeyAsText().string(); 
     dailyDeliverySum.add(new DailyDeliverySum(deliverySum, delivery, dateString)); 
    } 
    return dailyDeliverySum; 
} 
} 

它給我是正確的數據，但它不能滿足我所有的需求 假設我查詢10天的時間範圍，如果在給定的時間範圍內沒有數據它錯過了Date日期直方圖桶中的日期，但是如果沒有可用數據，我想設置0作爲默認值用於聚合和文檔計數。

有沒有什麼辦法可以做到這一點？

Answer 1

是的，你可以使用的date_histogram聚集"minimum document count" feature並將其設置爲0。這樣的話，你還可以得到不包含任何數據桶：

final AggregationBuilder<?> dailyDateHistogarm = 
    AggregationBuilders.dateHistogram(AggregationConstants.DAILY) 
     .field("dob")   
     .minDocCount(0)       <--- add this line 
     .interval(DateHistogram.Interval.DAY) 
     .subAggregation(aggregateArtifactcount);