子聚合
编辑子聚合编辑
一种特殊的单桶聚合，用于选择具有指定类型的子文档，如 join 字段 中定义的。
此聚合有一个选项
-
type- 应该选择的子类型。
例如，假设我们有一个问题和答案的索引。答案类型在映射中具有以下 join 字段
response = client.indices.create(
index: 'child_example',
body: {
mappings: {
properties: {
join: {
type: 'join',
relations: {
question: 'answer'
}
}
}
}
}
)
puts response
PUT child_example
{
"mappings": {
"properties": {
"join": {
"type": "join",
"relations": {
"question": "answer"
}
}
}
}
}
question 文档包含一个标签字段，而 answer 文档包含一个所有者字段。使用 children 聚合，即使这两个字段存在于两种不同类型的文档中，也可以在单个请求中将标签桶映射到所有者桶。
问题文档示例
response = client.index(
index: 'child_example',
id: 1,
body: {
join: {
name: 'question'
},
body: 'I have Windows 2003 server and i bought a new Windows 2008 server...',
title: 'Whats the best way to file transfer my site from server to a newer one?',
tags: [
'windows-server-2003',
'windows-server-2008',
'file-transfer'
]
}
)
puts response
PUT child_example/_doc/1
{
"join": {
"name": "question"
},
"body": "<p>I have Windows 2003 server and i bought a new Windows 2008 server...",
"title": "Whats the best way to file transfer my site from server to a newer one?",
"tags": [
"windows-server-2003",
"windows-server-2008",
"file-transfer"
]
}
answer 文档示例
response = client.index(
index: 'child_example',
id: 2,
routing: 1,
body: {
join: {
name: 'answer',
parent: '1'
},
owner: {
location: 'Norfolk, United Kingdom',
display_name: 'Sam',
id: 48
},
body: "Unfortunately you're pretty much limited to FTP...",
creation_date: '2009-05-04T13:45:37.030'
}
)
puts response
response = client.index(
index: 'child_example',
id: 3,
routing: 1,
refresh: true,
body: {
join: {
name: 'answer',
parent: '1'
},
owner: {
location: 'Norfolk, United Kingdom',
display_name: 'Troll',
id: 49
},
body: 'Use Linux...',
creation_date: '2009-05-05T13:45:37.030'
}
)
puts response
PUT child_example/_doc/2?routing=1
{
"join": {
"name": "answer",
"parent": "1"
},
"owner": {
"location": "Norfolk, United Kingdom",
"display_name": "Sam",
"id": 48
},
"body": "<p>Unfortunately you're pretty much limited to FTP...",
"creation_date": "2009-05-04T13:45:37.030"
}
PUT child_example/_doc/3?routing=1&refresh
{
"join": {
"name": "answer",
"parent": "1"
},
"owner": {
"location": "Norfolk, United Kingdom",
"display_name": "Troll",
"id": 49
},
"body": "<p>Use Linux...",
"creation_date": "2009-05-05T13:45:37.030"
}
可以构建以下请求将两者连接在一起
response = client.search(
index: 'child_example',
size: 0,
body: {
aggregations: {
"top-tags": {
terms: {
field: 'tags.keyword',
size: 10
},
aggregations: {
"to-answers": {
children: {
type: 'answer'
},
aggregations: {
"top-names": {
terms: {
field: 'owner.display_name.keyword',
size: 10
}
}
}
}
}
}
}
}
)
puts response
POST child_example/_search?size=0
{
"aggs": {
"top-tags": {
"terms": {
"field": "tags.keyword",
"size": 10
},
"aggs": {
"to-answers": {
"children": {
"type" : "answer"
},
"aggs": {
"top-names": {
"terms": {
"field": "owner.display_name.keyword",
"size": 10
}
}
}
}
}
}
}
}
上面的示例返回了热门问题标签，以及每个标签对应的热门答案所有者。
可能的响应
{
"took": 25,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped" : 0,
"failed": 0
},
"hits": {
"total" : {
"value": 3,
"relation": "eq"
},
"max_score": null,
"hits": []
},
"aggregations": {
"top-tags": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "file-transfer",
"doc_count": 1,
"to-answers": {
"doc_count": 2,
"top-names": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "Sam",
"doc_count": 1
},
{
"key": "Troll",
"doc_count": 1
}
]
}
}
},
{
"key": "windows-server-2003",
"doc_count": 1,
"to-answers": {
"doc_count": 2,
"top-names": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "Sam",
"doc_count": 1
},
{
"key": "Troll",
"doc_count": 1
}
]
}
}
},
{
"key": "windows-server-2008",
"doc_count": 1,
"to-answers": {
"doc_count": 2,
"top-names": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "Sam",
"doc_count": 1
},
{
"key": "Troll",
"doc_count": 1
}
]
}
}
}
]
}
}
}