如何使用Java API计算基于多个字段值的Elastic Search文档？

Question

I am attempting to count the number of documents of a specific type based on the value of 2 of the documents fields.

So far I can count the number of documents using:

SearchResponse response = elasticClient.getClient().prepareSearch(Properties.get().getSearch().getAliasName())
        .setTypes(type)
        .setSize(0) // Don't return any documents, we don't need them.
        .get();

SearchHits hits = response.getHits();
return (int) hits.getTotalHits();

Which returns the correct number of total documents.

I can also search for a specific document using:

    searchResponse = elasticClient.getClient()
            .prepareSearch(index)
            .setSearchType(SearchType.QUERY_THEN_FETCH)
            .setQuery(QueryBuilders.prefixQuery(field_name, field_value))
            .setFetchSource(true)
            .setSize(10000)
            .setTypes(type)
            .addSort(builder.order(SortOrder.DESC))
            .get();

This also returns documents.

I have attempted to count based on 2 field values using:

BoolQueryBuilder queryBuilder = QueryBuilders.boolQuery();
queryBuilder.must(QueryBuilders.prefixQuery(field_1, value_1));
queryBuilder.must(QueryBuilders.prefixQuery(field_2, value_2));
SearchRequestBuilder searchBuilder = elasticClient.getClient().prepareSearch(index)
        .setQuery(queryBuilder)
        .setTypes(type)
        .setSize(0);

But this always returns 0.

How do I correctly count documents based on 2 field values using the Java API?

Answer 1

From inspecting the query, you are not passing both values together. You are first passing the query for field_1 and later overwriting it with the query for field_2 . So the variable queryBuilder only has the query: QueryBuilders.prefixQuery(field_2, value_2) by the time you pass it to the client.

In elasticsearch query DSL, the must object is an array of queries that behave similar to an AND in a SQL where clause. So all the queries in the must list need to match. To include both queries in the must do the following:

BoolQueryBuilder queryBuilder = QueryBuilders.boolQuery();
queryBuilder.must().add(QueryBuilders.prefixQuery(field_1, value_1));
queryBuilder.must().add(QueryBuilders.prefixQuery(field_2, value_2));

As for the count, size = 0 should do the trick. What kind of elasticsearch client are you using?