[英]c# Nest and Elasticsearch Aggregations
有谁知道如何使用嵌套进行多次聚合? 不幸的是,我发现了很多示例,但它们都不起作用。
这是我所拥有的:
Vehicles fields = new Vehicles();
//create a terms query
var query = new TermsQuery
{
IsVerbatim = true,
Field = "VehicleOwnerId",
Terms = new string[] { 25 },
};
var aggregations = new Dictionary<string, IAggregationContainer>
{
{ "years", new AggregationContainer
{
Terms = new TermsAggregation(nameof(fields.Year))
{
Field = new Field(nameof(fields.Year))
}
}
}
//,
//{ "makes", new AggregationContainer
// {
// Terms = new TermsAggregation("Make")
// {
// Field = new Field(nameof(fields.Make))
// }
// }
//}
};
//create the search request
var searchRequest = new SearchRequest
{
Query = query,
From = 0,
Size = 100,
Aggregations = aggregations
};
var result = client.SearchAsync<InventoryLiveView>(searchRequest).Result;
var years = result.Aggregations.Terms("years");
Dictionary<string, long> yearCounts = new Dictionary<string, long>();
foreach (var item in years.Buckets)
{
yearCounts.Add(item.Key, item.DocCount ?? 0);
}
如果我只是像这样执行代码,它就可以工作。 年按预期返回聚合。 如果我尝试添加另一个字段(如上面注释的那个),它会失败并且我得到零记录。 如何在一个查询中获得多个聚合? 我到处都看到了它的例子,但我尝试过的例子似乎都没有工作,而且大多数似乎已经过时了(包括 Nest 文档中的一些)。 我也尝试过这种与文档非常接近的方法。
//create the search request
var searchRequest = new SearchRequest
{
Query = query,
From = 0,
Size = 100,
//Aggregations = aggregations
Aggregations = new AggregationDictionary
{
{
"childAgg", new ChildrenAggregation("childAgg", typeof(Vehicles ))
{
Aggregations = new AggregationDictionary
{
{"years", new TermsAggregation(nameof(fields.VehicleYear))},
{"makes", new TermsAggregation(nameof(fields.VehicleMakeName))},
{"models", new TermsAggregation(nameof(fields.VehicleModelName))},
}
}
}
}
};
var result = client.SearchAsync<Vehicles>(searchRequest).Result;
这只会产生一个空引用异常。
我想我永远都不会为成为一名程序员而感到骄傲:)解决问题的方法常常使我感到愚蠢,因为它暴露了自己。
所以我的问题是,我试图在聚合中使用的字段是文本,无法使用。 我将所有内容都切换到了ID字段,并且多个聚合按预期工作。
因此,此版本的代码像冠军一样工作:
Vehicle fields = new Vehicle ();
//create a terms query
var query = new TermsQuery
{
IsVerbatim = true,
Field = "VehicleOwnerId",
Terms = new string[] { "30" },
};
string[] Fields = new[]
{
nameof(fields.Year),
nameof(fields.MakeId),
nameof(fields.ModelId)
};
var aggregations = new Dictionary<string, IAggregationContainer>();
foreach (string sField in Fields)
{
var termsAggregation = new TermsAggregation(sField)
{
Field = sField
};
aggregations.Add(sField, new AggregationContainer { Terms = termsAggregation });
}
//create the search request
var searchRequest = new SearchRequest
{
Query = query,
From = 0,
Size = 10,
Aggregations = aggregations
};
var result = client.SearchAsync<InventoryLiveView>(searchRequest).Result;
var years = result.Aggregations.Terms(nameof(fields.Year));
Dictionary<string, long> yearCounts = new Dictionary<string, long>();
foreach (var item in years.Buckets)
{
yearCounts.Add(item.Key, item.DocCount ?? 0);
}
我使用邮差看到的来自Elasticsearch的确切错误是:
Fielddata is disabled on text fields by default. Set fielddata=true on [MakeName] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead.
这是我使用 SearchDescriptors 的示例。 我唯一的问题是如何将返回的结果序列化为正确的键值列表。 循环遍历字段列表是返回结果的最佳方式。
SearchDescriptor<Advert> agghDescriptor = new SearchDescriptor<Advert>();
agghDescriptor.Aggregations(ag => ag.Terms("make", a => a.Field(f => f.Make)) &&
ag.Terms("region", a => a.Field(f => f.Region)) &&
ag.Terms("city", a => a.Field(f => f.City)) &&
ag.Terms("category", a => a.Field(f => f.Category)) &&
ag.Terms("application", a => a.Field(f => f.Application)) &&
ag.Terms("portalId", a => a.Field(f => f.PortalId)) &&
ag.Terms("isActiveAuctionAdvert", a => a.Field(f => f.IsActiveAuctionAdvert)) &&
ag.Terms("isBargainAccount", a => a.Field(f => f.IsBargainAccount)) &&
ag.Terms("condition", a => a.Field(f => f.Condition))
);
agghDescriptor.Size(0);
var json2 = _client.RequestResponseSerializer.SerializeToString(agghDescriptor);
var aggregationResult = _client.Search<Advert>(agghDescriptor);
List<string> fields = new List<string>();
fields.Add("make");
fields.Add("category");
fields.Add("region");
List<Aggregation> aggregations = new List<Aggregation>();
foreach (var field in fields)
{
var aggrs = aggregationResult.Aggregations.Terms(field);
List<AggregateItem> aggregateItems = new List<AggregateItem>();
foreach (var item in aggrs.Buckets)
{
aggregateItems.Add(new AggregateItem()
{
Count = item.DocCount ?? 0,
Key = item.Key
});
}
aggregations.Add(new Aggregation()
{
Name = field,
Aggregates = aggregateItems
});
}
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