How to get search hits results when executing aggregation? - elasticsearch

Question

As stated in the ElasticSearch documentation:
In Elasticsearch, you have the ability to execute searches returning hits and at the same time return aggregated results separate from the hits all in one response. This is very powerful and efficient in the sense that you can run queries and multiple aggregations and get the results back of both (or either) operations in one shot avoiding network roundtrips using a concise and simplified API.
I want to execute searches returning hits when i have queries out for the aggregation. But i am not sure how can i achieve the above?
I am using the following query:
curl -XPOST 'localhost:9200/employee/_search?pretty' -d '
{
"size": 0,
"aggs": {
"group_by_domain": {
"terms": {
"field": "domain"
}
}
}
}'
and here is the result which i am getting,
{
"took" : 92,
"timed_out" : false,
"_shards" : {
"total" : 5,
"successful" : 5,
"failed" : 0
},
"hits" : {
"total" : 1000,
"max_score" : 0.0,
"hits" : [ ]
},
"aggregations" : {
"group_by_domain" : {
"doc_count_error_upper_bound" : 5,
"sum_other_doc_count" : 744,
"buckets" : [ {
"key" : "finance",
"doc_count" : 30
}]
}
}
}
As we can see that the hits array is empty. I am not sure how to get those hits array. Any suggestion?

Answer 1

the hits are empty because you have set the size of the returning query to 0 when you specify:
"size": 0,
you can remove size completely and in this case you'll get 10 hits that is the default or you can set the size you want, for instance if you specify 100 you'll get 100 hits in response. This is related to the search results.
Now, if you also want to get results in the aggregation you can use Top Hits Aggregation for that.