ElasticSearch DateHistogram聚合填充缺失数据

Question

我试图使用ElasticSearch春天的数据对于一些聚合

，这里是我的查询

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()); 

而且这是我的汇聚

 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; 
} 
} 

它给我是正确的数据，但它不能满足我所有的需求 假设我查询10天的时间范围，如果在给定的时间范围内没有数据它错过了Date日期直方图桶中的日期，但是如果没有可用数据，我想设置0作为默认值用于聚合和文档计数。

有没有什么办法可以做到这一点？

Answer 1

是的，你可以使用的date_histogram聚集"minimum document count" feature并将其设置为0。这样的话，你还可以得到不包含任何数据桶：

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