[英]c# ElasticSearch NEST aggregation: group by
我的 ES NEST 查询有问题。 它“创建组”,但项目列表为空。 我查找了示例并阅读了我发现的内容,但结果仍然是空的。
这是我的查询:
public partial class ElasticSearchService
{
private const string groupBySubCategoryKey = "SubCategoryKey";
public async Task SiteMap()
{
ISearchResponse<AdvertisementObjectEntityExtended> result = await Client.SearchAsync<AdvertisementObjectEntityExtended>(s => s
.Index(ElasticClientFactorySettings.AdvertisementObjectIndex)
.Aggregations(agr =>
agr.Terms(groupBySubCategoryKey,
g => g.Field(f =>
f.SubCategoryKey))));
var r = result.Aggregations.Terms(groupBySubCategoryKey);
} }
public static class ElasticClientFactory
{
public static async Task<ElasticClient> ClientAsync(ElasticSearchSettings settings)
{
Uri uri = new Uri($"{settings.EndPoint}");
ConnectionSettings ConnectionSettings = new ConnectionSettings(uri)
.DefaultIndex(ElasticClientFactorySettings.AdvertisementObjectIndex)
.DefaultMappingFor<AdvertisementObjectEntityExtended>(i => i.IndexName(ElasticClientFactorySettings.AdvertisementObjectIndex))
.EnableHttpCompression()
.PrettyJson();
ElasticClient client = new ElasticClient(ConnectionSettings);
CreateIndexResponse createIndexResponse = await client.Indices.CreateAsync(ElasticClientFactorySettings.AdvertisementObjectIndex, c => c
.Map<AdvertisementObjectEntityExtended>(m => m
.AutoMap()
.Properties(p => p
.Text(t => t.Name(n => n.Id).Analyzer(AnalyzerSettings.No))
.Text(t => t.Name(n => n.UserUniq).Analyzer(AnalyzerSettings.NotAnalyzed))
.Text(t => t.Name(n => n.Uniq).Analyzer(AnalyzerSettings.NotAnalyzed))
.Text(t => t.Name(n => n.MainCategoryKey).Analyzer(AnalyzerSettings.NotAnalyzed))
.Text(t => t.Name(n => n.SubCategoryKey).Analyzer(AnalyzerSettings.NotAnalyzed))
.Nested<List<string>>(n => n.Name(nn => nn.Images)
)
)
)
);
return client;
}
}
public partial class ElasticSearchService : IElasticSearchService
{
public ElasticSearchService(IOptions<ElasticSearchSettings> settings)
{
Client = ElasticClientFactory.ClientAsync(settings.Value).Result;
}
}
任何的想法? 谢谢
问题是您的映射属于文本类型。
要在文本字段上进行术语聚合,您需要为该字段打开 fielddata。 https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-bucket-terms-aggregation.html#CO255-1
但是您可能真正想要的是使用关键字字段而不是文本,它会自动与术语聚合一起使用。 默认情况下不分析它们。 因此,对映射的以下更改应该可以解决问题:
.Keyword(t => t.Name(n => n.Id))
.Keyword(t => t.Name(n => n.UserUniq))
.Keyword(t => t.Name(n => n.Uniq))
.Keyword(t => t.Name(n => n.MainCategoryKey))
.Keyword(t => t.Name(n => n.SubCategoryKey))
现在我应该补充一点,如果图像是字符串列表,则不需要进行嵌套映射。 字符串列表基本上与 elasticsearch 中的单个字符串相同,因此您可以执行以下操作:
.Keyword(t => t.Name(n => nn.Images))
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