Getting only aggregations results in elasticsearch

Question

I am doing aggregation like this:

  {
   "size":0,
   "aggs":
    {
      "my_aggs":
      {
         "terms":
          {
            "field":"my_field"
          }
      }
   }
}

I want to get only the aggregation result. So when I set size=0 like below, it gives error-later learned this is for how many results I want(aggregations). So, how can I achieve this to get only the aggregation results(no hits result docs)

AbstractAggregationBuilder aggregationBuilder = AggregationBuilders
                .terms("my_aggs")
                .field("my_field")
                .size(0) //how to set size for my purpose?
                .order(BucketOrder.key(true));

Moreover, If I get thousands of aggregation results, does this query return all of them? or apply to its default 10 size? If not, how do know how many should I set size of aggregation result.


Edit I am adding my aggregation like this:

 SearchQuery searchQuery = new NativeSearchQueryBuilder()
                .withIndices(indexName)
                .withTypes(typeName)
                .withQuery(boolQueryBuilder)
                .addAggregation(aggregationBuilder)
                .build();

Please help.

Answer 1

You do that on the SearchRequest instance not at the aggregation level:

AbstractAggregationBuilder aggregationBuilder = AggregationBuilders
            .terms("my_aggs")
            .field("my_field")
            .order(BucketOrder.key(true));

SearchQuery searchQuery = new NativeSearchQueryBuilder()
            .withIndices(indexName)
            .withTypes(typeName)
            .withQuery(boolQueryBuilder)
            .withPageable(new PageRequest(0, 1))       <--- add this
            .addAggregation(aggregationBuilder)
            .build();

As far as I know, Spring Data ES doesn't allow you to create a PageRequest with size 0 (hence why I picked 1). If that's a problem, this answer shows you how to override that behavior.

By default, your aggregation will return 10 buckets, but you can increase the size up to 10000, if needed.