ElasticSearch聚合返回整个子对象，而不仅仅是键

Question

使用ElasticSearch的新手，我们使用以下结构索引文档:

{
"Id": 1246761,
"ContentTypeName": "Official Statement",
"Title": "Official statement Title",    
"Categories": [
{
"Id": 3,
"Type": 1,
"Name": "Category A",
"ParentId": 0
},
{
"Id": 10,
"Type": 3,
"Name": "Category B",
"ParentId": 0
},
{
"Id": 426,
"Type": 7,
"Name": "Category C",
"ParentId": 0
}
]
}

要求是获得与关键字搜索匹配的类别+文档计数的聚合列表。到目前为止，我们的查询看起来像这样:

GET _search
{
"query": {
"match_all": {}
},
"size": 0,
"aggs": {
"my-agg-name": {
"terms": {
"field": "Categories.Id"
}
}
}
}

结果

{
"hits" : {
"total" : {
"value" : 10000,
"relation" : "gte"
},
"max_score" : null,
"hits" : [ ]
},
"aggregations" : {
"my-agg-name" : {
"doc_count_error_upper_bound" : 23845,
"sum_other_doc_count" : 1068245,
"buckets" : [
{
"key" : 426,
"doc_count" : 112651
},
{
"key" : 10,
"doc_count" : 91146
},

....
]
}
}
}

是否有一种方法可以返回整个类别对象，而不仅仅是Id ?还是将类别对象序列化为字符串作为键?

Answer 1

您需要使用嵌套聚合来实现所需的用例

添加包含索引映射、搜索查询和搜索结果的工作示例

指数映射:

{
"mappings": {
"properties": {
"Categories": {
"type": "nested"
}
}
}
}

搜索查询:

{
"query": {
"match_all": {}
},
"aggs": {
"resellers": {
"nested": {
"path": "Categories"
},
"aggs": {
"my-agg-name": {
"terms": {
"field": "Categories.Id"
},
"aggs": {
"categories-doc": {
"top_hits": {
"_source": {
"includes": [
"Categories.Id",
"Categories.Type",
"Categories.Name",
"Categories.ParentId"
]
},
"size": 1
}
}
}
}
}
}
}
}

搜索结果:

"aggregations": {
"resellers": {
"doc_count": 3,
"my-agg-name": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": 3,                    // note this
"doc_count": 1,
"categories-doc": {
"hits": {
"total": {
"value": 1,
"relation": "eq"
},
"max_score": 1.0,
"hits": [
{
"_index": "65847850",
"_type": "_doc",
"_id": "1",
"_nested": {
"field": "Categories",
"offset": 0
},
"_score": 1.0,
"_source": {
"ParentId": 0,
"Type": 1,
"Id": 3,                     // note this
"Name": "Category A"
}
}
]
}
}
},
{
"key": 10,
"doc_count": 1,
"categories-doc": {
"hits": {
"total": {
"value": 1,
"relation": "eq"
},
"max_score": 1.0,
"hits": [
{
"_index": "65847850",
"_type": "_doc",
"_id": "1",
"_nested": {
"field": "Categories",
"offset": 1
},
"_score": 1.0,
"_source": {
"ParentId": 0,
"Type": 3,
"Id": 10,
"Name": "Category B"
}
}
]
}
}
},
{
"key": 426,
"doc_count": 1,
"categories-doc": {
"hits": {
"total": {
"value": 1,
"relation": "eq"
},
"max_score": 1.0,
"hits": [
{
"_index": "65847850",
"_type": "_doc",
"_id": "1",
"_nested": {
"field": "Categories",
"offset": 2
},
"_score": 1.0,
"_source": {
"ParentId": 0,
"Type": 7,
"Id": 426,
"Name": "Category C"
}
}
]
}
}
}
]
}
}
}