如何在弹性搜索中避免使用嵌套类型的跨对象搜索行为

Question

我试图确定在弹性搜索中索引文档的最佳方法.我有一个文档Doc,它有一些字段:

Doc
  created_at
  updated_at
  field_a
  field_b

但Doc也会有一些特定于个人用户的字段.例如,field_x对于用户1将具有值"A",并且field_x将具有用于用户2的值"B".对于每个文档,将存在非常有限数量的用户(通常为2,最多~10).当用户搜索field_x时,他们必须搜索属于它们的值.我一直在探索ES中的嵌套类型.

Doc
  created_at
  updated_at
  field_x: [{
    user: 1
    field_x: A
  },{
    user: 2
    field_x: B
  }]

当用户1在field_x上搜索值"A"时,此文档应该会受到影响.但是,当用户1按值'B'搜索时,不应该这样.

但是,根据文档:

索引在doc中多次出现的内部对象时的一个问题是将发生"交叉对象"搜索匹配

有没有办法避免嵌套类型的这种行为或我应该探索另一种类型？

有关此类查询执行情况的其他信息非常有价值.仅仅从阅读文档开始,它就表明嵌套查询在性能方面与常规查询相比并没有太大差异.如果有人真正体验过这一点,我很乐意听到.

Answer 1

嵌套类型是您正在寻找的,并且不要过于担心性能.

在索引文档之前,您需要设置文档的映射:

curl -XDELETE localhost:9200/index
curl -XPUT localhost:9200/index
curl -XPUT localhost:9200/index/type/_mapping -d '{
    "type": {
        "properties": {
            "field_x": {
                "type": "nested",
                "include_in_parent": false,
                "include_in_root": false,
                "properties": {
                    "user": {
                        "type": "string"
                    },
                    "field_x": {
                        "type": "string",
                        "index" : "not_analyzed" // NOTE*
                    }
                }
            }
        }
    }
}'

*注意:如果您的字段实际上只包含诸如"A"和"B"之类的单数字母,则您不希望分析该字段,否则elasticsearch将删除这些单数字母"单词".如果这只是您的示例,并且在您的真实文档中,您正在搜索正确的单词,请删除此行并让elasticsearch分析该字段.

然后,索引您的文档:

curl -XPUT http://localhost:9200/index/type/1 -d '
{ 
    "field_a": "foo",
    "field_b": "bar",
    "field_x" : [{
        "user" : "1",
        "field_x" : "A"
    },
    {
        "user" : "2",
        "field_x" : "B"
    }]
}'

并运行您的查询:

curl -XGET localhost:9200/index/type/_search -d '{ 
    "query": {
        "nested" : {
            "path" : "field_x",
            "score_mode" : "avg",
            "query" : {
                "bool" : {
                    "must" : [
                        {
                            "term": {
                                "field_x.user": "1"
                            }
                        },
                        {
                            "term": {
                                "field_x.field_x": "A"
                            }
                        }
                    ]
                }
            }
        }
    }
}';

这将导致

{"took":13,"timed_out":false,"_shards":{"total":5,"successful":5,"failed":0},"hits":{"total":1,"max_score":1.987628,"hits":[{"_index":"index","_type":"type","_id":"1","_score":1.987628, "_source" : 
{ 
    "field_a": "foo",
    "field_b": "bar",
    "field_x" : [{
        "user" : "1",
        "field_x" : "A"
    },
    {
        "user" : "2",
        "field_x" : "B"
    }]
}}]}}

但是,查询

curl -XGET localhost:9200/index/type/_search -d '{ 
    "query": {
        "nested" : {
            "path" : "field_x",
            "score_mode" : "avg",
            "query" : {
                "bool" : {
                    "must" : [
                        {
                            "term": {
                                "field_x.user": "1"
                            }
                        },
                        {
                            "term": {
                                "field_x.field_x": "B"
                            }
                        }
                    ]
                }
            }
        }
    }
}';

不会返回任何结果

{"took":6,"timed_out":false,"_shards":{"total":5,"successful":5,"failed":0},"hits":{"total":0,"max_score":null,"hits":[]}}