How to return all documents for each bucket after ElasticSearch term aggregation?

Question

I use the following simple query to search across documents in my Elastic index:

{
    "query": { "query_string": { "query": "*test*" } },
    "aggregations": {
        "myaggregation": {
            "terms": { "field": "myField.raw", "size": 0 }
        }
    }
}

This returns me the number of documents per distinct value of myField.raw.

Since I'm interested into all actual documents than the total number, I tried to add the following top_hits sub aggregation:

{
    "query": { "query_string": { "query": "*test*" } },
    "aggregations": {
        "myaggregation": {
            "terms": { "field": "myField.raw", "size": 0 },
            "aggregations": {
                "hits": {
                    "top_hits": { "size": 2000000 }
                }
            }
        }
    }
}

This ugly usage of top_hits works, but is slow as hell.

Is there any proper way to fetch the actual documents for each bucket after doing the term aggregation?

Answer 1

Have you considered using collapse on field?

It returns doc grouped under inner_hits (hits.hits[].inner_hits.<collapse-group-name>.hits.hits[]._source)

Refer - https://www.elastic.co/guide/en/elasticsearch/reference/6.8/search-request-collapse.html