ElasticSearch DateHistogram Aggregation Fill Missing Data

Question

I'm trying to use ElasticSearch spring data for some aggregations

Here Is my query

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());

Also this is my Aggregation

        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;
}
}

It gives me the correct data , But It doesn't satisfy all my needs Suppose if I query for time range of 10 days , If there is no data for a date in the given time range It miss that date in Date histogram buckets ,But I want to set 0 as default value for aggregation and doc count if there is no data available

Is there any way to do it ??

Answer 1

Yes, you can use the "minimum document count" feature of the date_histogram aggregation and set it to 0. That way, you'll also get buckets that don't contain any data:

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