elasticsearch - 具有After功能的复合聚合

Question

我正在寻找带有NEST lib的After功能用法的代码片段。
https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-bucket-composite-aggregation.html#_after。

预先感谢您的代码片段

Answer 1

您可以将以前的组合聚合中的CompositeKey传递为新的组合聚合的.After()参数。例如

var pool = new SingleNodeConnectionPool(new Uri("http://localhost:9200"));
var settings = new ConnectionSettings(pool);
var client = new ElasticClient(settings);

var searchResponse = client.Search<object>(s => s
    .From(0)
    .AllIndices()
    .AllTypes()
    .Aggregations(a => a
        .Composite("composite_agg", c => c
            .Sources(so => so
                .DateHistogram("date", dh => dh
                    .Field("timestamp")
                    .Interval("1d")
                )
                .Terms("product", t => t
                    .Field("product")
                )
            )
        )
    )
);

var compositeAgg = searchResponse.Aggregations.Composite("composite_agg");

searchResponse = client.Search<object>(s => s
    .From(0)
    .AllIndices()
    .AllTypes()
    .Aggregations(a => a
        .Composite("composite_agg", c => c
            .Sources(so => so
                .DateHistogram("date", dh => dh
                    .Field("timestamp")
                    .Interval("1d")
                )
                .Terms("product", t => t
                    .Field("product")
                )
            )
            .After(compositeAgg.AfterKey) // <-- pass the after key from previous agg response
        )
    )
);

假设您正在使用Elasticsearch 6.x(必须使用Composite Aggregation)，请将NEST客户端更新为最新版本(当前为6.6.0)，因为它包含 bug fix for a CompositeKey with null values。