java : get distinct values from an elasticsearch index

Question

Currently I'm using this code which I had written to get the values from a field :

QueryBuilder qb = QueryBuilders.matchPhrasePrefixQuery("tagName", "june");
            SearchResponse response = esclient.prepareSearch(index).setTypes(type)
                    .setQuery(qb)
                    .execute().actionGet();

            SearchHit[] hits = response.getHits().getHits();
            System.out.println(hits.length);

            for (SearchHit hit : hits) {
                Map map = hit.getSource();
                System.out.println((String) map.get("tagName"));
                strings.add((String) map.get("tagName"));
            }

But is there an alternative to get distinct values from an index? Or can the above can be modified?

Please look in this question. if you are able to help https://stackoverflow.com/questions/59570496/elasticsearch-error-invalid-term-aggregator-order-path-key-unknown-aggregat — Siva, Jan 02 '20 at 22:05

score 1 · Accepted Answer · answered Feb 12 '18 at 15:34

You Can Use terms aggregation

This requires the field to be not analyzed.

    public static List<String> getDistinctAgg(TransportClient client, String indexName, String fieldName, int requiredSize) {
    List<String> values = new LinkedList<>();

    try {


        TermsAggregationBuilder aggregationBuilder = new TermsAggregationBuilder(fieldName + "_Agg", ValueType.STRING);
        aggregationBuilder.field(fieldName);
        aggregationBuilder.bucketCountThresholds(new TermsAggregator.BucketCountThresholds(1, 1, requiredSize, 5));

        QueryBuilder query = QueryBuilders.matchAllQuery();


        SearchResponse response = client.prepareSearch(indexName)
                .setSearchType(SearchType.DFS_QUERY_THEN_FETCH)
                .setQuery(query).addAggregation(aggregationBuilder).setSize(0).get();
        if (response == null) return null;

        StringTerms terms = ((StringTerms) response.getAggregations().get(fieldName + "_Agg"));

        if (terms != null) {

            List<Terms.Bucket> buckets = terms.getBuckets();
            if (buckets != null && buckets.size() > 0) {


                for (Terms.Bucket bucket : buckets) {
                    values.add(bucket.getKeyAsString());
                }
            }
            return values;
        }

    } catch (Exception e) {
        return null;
    }
    return null;
}

java : get distinct values from an elasticsearch index

1 Answers1