Elasticsearch 学习之Field Collapsing（字段折叠）

Field Collapsing（字段折叠）不能与scroll、rescore以及search after 结合使用

• collapse字段：表示按照age（每个age对应多条document结果）的值折叠（keyword或者数值）
• sort：表示按照age字段排序

• from：偏移，即前180个document的值都被折叠掉了

  curl -XGET "http://localhost:9200/bank/_search" -H 'Content-Type: application/json' -d'
  {
  "query": {
  "match": {
  "address": "Place"
  }
  },
  "collapse" : {
  "field" : "age"
  },
  "sort": ["age"],
  "from": 10
  }''

• Expand collapse results（对于每个折叠的结果，可以通过inner_hits展开结果）

  max_concurrent_group_searches：允许每组检索inner_hits的并发请求数 (默认按照线程池的大小或者数据节点数）

• 单个inner_hits

  curl -XGET "http://localhost:9200/bank/_search" -H 'Content-Type: application/json' -d'
  {
  "query": {
  "match": {
  "address": "Place"
  }
  },
  "collapse" : {
  "field" : "age",
  "inner_hits": {
  "name": "test",
  "size": 5,
  "sort": [{ "age": "asc" }]
  },
  "max_concurrent_group_searches": 4
  },
  "sort": ["age"]
  }'

• 多个inner_hits

  curl -XGET "http://localhost:9200/bank/_search" -H 'Content-Type: application/json' -d'
  {
  "query": {
  "match": {
  "address": "Place"
  }
  },
  "collapse" : {
  "field" : "age",
  "inner_hits":[ {
  "name": "age",
  "size": 2,
  "sort": [{ "age": "asc" }]
  },
  {
  "name":"account_number",
  "size": 2,
  "sort": [{ "account_number": "asc" }]
  }],
  "max_concurrent_group_searches": 4
  },
  "sort": ["age"]
  }'