齐齐哈尔二手房出售:常用ElasticSearch 查询语句

2020-10-13 60 views 2

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为了演示差别类型的 ElasticSearch 的查询,我们将使用书文档信息的聚集(有以下字段:title(题目), authors(作者), summary(摘要), publish_date(公布日期)和 num_reviews(浏览数))。

在这之前,首先我们应该先建立一个新的索引(index),并批量导入一些文档:

建立索引:

PUT /bookdb_index
    { "settings": { "number_of_shards": 1 }} 

 

批量上传文档:

POST /bookdb_index/book/_bulk
    { "index": { "_id": 1 }}
    { "title": "Elasticsearch: The Definitive Guide", "authors": ["clinton gormley", "zachary tong"], "summary" : "A distibuted real-time search and analytics engine", "publish_date" : "2015-02-07", "num_reviews": 20, "publisher": "oreilly" }
    { "index": { "_id": 2 }}
    { "title": "Taming Text: How to Find, Organize, and Manipulate It", "authors": ["grant ingersoll", "thomas morton", "drew farris"], "summary" : "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization", "publish_date" : "2013-01-24", "num_reviews": 12, "publisher": "manning" }
    { "index": { "_id": 3 }}
    { "title": "Elasticsearch in Action", "authors": ["radu gheorge", "matthew lee hinman", "roy russo"], "summary" : "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms", "publish_date" : "2015-12-03", "num_reviews": 18, "publisher": "manning" }
    { "index": { "_id": 4 }}
    { "title": "Solr in Action", "authors": ["trey grainger", "timothy potter"], "summary" : "Comprehensive guide to implementing a scalable search engine using Apache Solr", "publish_date" : "2014-04-05", "num_reviews": 23, "publisher": "manning" }

 

栗子:

1. 基本的匹配(Query)查询

有两种方式来执行一个全文匹配查询:

  • 使用 Search Lite API,它从 url 中读取所有的查询参数
  • 使用完整 JSON 作为请求体,这样你可以使用完整的 Elasticsearch DSL

下面是一个基本的匹配查询,查询任一字段包罗 Guide 的纪录

GET /bookdb_index/book/_search?q=guide

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "1",
        "_score": 0.28168046,
        "_source": {
          "title": "Elasticsearch: The Definitive Guide",
          "authors": ["clinton gormley", "zachary tong"],
          "summary": "A distibuted real-time search and analytics engine",
          "publish_date": "2015-02-07",
          "num_reviews": 20,
          "publisher": "manning"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "4",
        "_score": 0.24144039,
        "_source": {
          "title": "Solr in Action",
          "authors": ["trey grainger", "timothy potter"],
          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
          "publish_date": "2014-04-05",
          "num_reviews": 23,
          "publisher": "manning"
        }
      }
    ]

 

下面是完整 Body 版本的查询,天生相同的内容:

{
    "query": {
        "multi_match" : {
            "query" : "guide",
            "fields" : ["_all"]
        }
    }
}

 

multi_matchmatch 的作为在多个字段运行相同操作的一个速记法。fields 属性用来指定查询针对的字段,在这个例子中,我们想要对文档的所有字段举行匹配。两个 API 都允许你指定要查询的字段。例如,查询 title 字段中包罗 in Action 的书:

GET /bookdb_index/book/_search?q=title:in action

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "4",
        "_score": 0.6259885,
        "_source": {
          "title": "Solr in Action",
          "authors": [
            "trey grainger",
            "timothy potter"
          ],
          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
          "publish_date": "2014-04-05",
          "num_reviews": 23,
          "publisher": "manning"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "3",
        "_score": 0.5975345,
        "_source": {
          "title": "Elasticsearch in Action",
          "authors": [
            "radu gheorge",
            "matthew lee hinman",
            "roy russo"
          ],
          "summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",
          "publish_date": "2015-12-03",
          "num_reviews": 18,
          "publisher": "manning"
        }
      }
    ]

 

然而, 完整的 DSL 给予你天真建立更庞大查询和指定返回效果的能力(后面,我们会逐一论述)。在下面例子中,我们指定 size 限制返回的效果条数,from 指定起始位子,_source 指定要返回的字段,以及语法高亮

POST /bookdb_index/book/_search
{
    "query": {
        "match" : {
            "title" : "in action"
        }
    },
    "size": 2,
    "from": 0,
    "_source": [ "title", "summary", "publish_date" ],
    "highlight": {
        "fields" : {
            "title" : {}
        }
    }
}

[Results]
"hits": {
    "total": 2,
    "max_score": 0.9105287,
    "hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "3",
        "_score": 0.9105287,
        "_source": {
          "summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",
          "title": "Elasticsearch in Action",
          "publish_date": "2015-12-03"
        },
        "highlight": {
          "title": [
            "Elasticsearch <em>in</em> <em>Action</em>"
          ]
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "4",
        "_score": 0.9105287,
        "_source": {
          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
          "title": "Solr in Action",
          "publish_date": "2014-04-05"
        },
        "highlight": {
          "title": [
            "Solr <em>in</em> <em>Action</em>"
          ]
        }
      }
    ]
  }

 

注重:对于多个词查询,match 允许指定是否使用 and 操作符来取代默认的 or 操作符。你还可以指定 mininum_should_match 选项来调整返回效果的相关水平。详细看后面的例子。

2. 多字段(Multi-filed)查询

正如我们已经看到来的,为了凭据多个字段检索(e.g. 在 titlesummary 字段都是相同的查询字符串的效果),你可以使用 multi_match 语句

POST /bookdb_index/book/_search
{
    "query": {
        "multi_match" : {
            "query" : "elasticsearch guide",
            "fields": ["title", "summary"]
        }
    }
}

[Results]
"hits": {
    "total": 3,
    "max_score": 0.9448582,
    "hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "1",
        "_score": 0.9448582,
        "_source": {
          "title": "Elasticsearch: The Definitive Guide",
          "authors": [
            "clinton gormley",
            "zachary tong"
          ],
          "summary": "A distibuted real-time search and analytics engine",
          "publish_date": "2015-02-07",
          "num_reviews": 20,
          "publisher": "manning"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "3",
        "_score": 0.17312013,
        "_source": {
          "title": "Elasticsearch in Action",
          "authors": [
            "radu gheorge",
            "matthew lee hinman",
            "roy russo"
          ],
          "summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",
          "publish_date": "2015-12-03",
          "num_reviews": 18,
          "publisher": "manning"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "4",
        "_score": 0.14965448,
        "_source": {
          "title": "Solr in Action",
          "authors": [
            "trey grainger",
            "timothy potter"
          ],
          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
          "publish_date": "2014-04-05",
          "num_reviews": 23,
          "publisher": "manning"
        }
      }
    ]
  }

 

:第三条被匹配,由于 guidesummary 字段中被找到。

3. Boosting

由于我们是多个字段查询,我们可能需要提高某一个字段的分值。在下面的例子中,我们把 summary 字段的分数提高三倍,为了提升 summary 字段的主要度;因此,我们把文档 4 的相关度提高了。

POST /bookdb_index/book/_search
{
    "query": {
        "multi_match" : {
            "query" : "elasticsearch guide",
            "fields": ["title", "summary^3"]
        }
    },
    "_source": ["title", "summary", "publish_date"]
}

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "1",
        "_score": 0.31495273,
        "_source": {
          "summary": "A distibuted real-time search and analytics engine",
          "title": "Elasticsearch: The Definitive Guide",
          "publish_date": "2015-02-07"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "4",
        "_score": 0.14965448,
        "_source": {
          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
          "title": "Solr in Action",
          "publish_date": "2014-04-05"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "3",
        "_score": 0.13094766,
        "_source": {
          "summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",
          "title": "Elasticsearch in Action",
          "publish_date": "2015-12-03"
        }
      }
    ]

 

:提升不是简简朴单通过提升因子把盘算分数加成。现实的 boost 值通过归一化和一些内部优化给出的。相关信息请见 Elasticsearch guide

4. Bool 查询

为了提供更相关或者特定的效果,AND/OR/NOT 操作符可以用来调整我们的查询。它是以 布尔查询 的方式来实现的。布尔查询 接受如下参数:

  • must 等同于 AND
  • must_not 等同于 NOT
  • should 等同于 OR

打比方,若是我想要查询这样类型的书:书名包罗 ElasticSearch 或者(ORSolr,而且(AND)它的作者是 Clinton Gormley 不是(NOTRadu Gheorge

POST /bookdb_index/book/_search
{
    "query": {
        "bool": {
            "must": {
                "bool" : { "should": [
                      { "match": { "title": "Elasticsearch" }},
                      { "match": { "title": "Solr" }} ] }
            },
            "must": { "match": { "authors": "clinton gormely" }},
            "must_not": { "match": {"authors": "radu gheorge" }}
        }
    }
}

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "1",
        "_score": 0.3672021,
        "_source": {
          "title": "Elasticsearch: The Definitive Guide",
          "authors": [
            "clinton gormley",
            "zachary tong"
          ],
          "summary": "A distibuted real-time search and analytics engine",
          "publish_date": "2015-02-07",
          "num_reviews": 20,
          "publisher": "oreilly"
        }
      }
    ]

 

:正如你所看到的,布尔查询 可以包装任何其他查询类型,包罗其他布尔查询,以建立随便庞大或深度嵌套的查询。

5. 模糊(Fuzzy)查询

在举行匹配和多项匹配时,可以启用模糊匹配来捕捉拼写错误,模糊度是基于原始单词的编辑距离来指定的。

POST /bookdb_index/book/_search
{
    "query": {
        "multi_match" : {
            "query" : "comprihensiv guide",
            "fields": ["title", "summary"],
            "fuzziness": "AUTO"
        }
    },
    "_source": ["title", "summary", "publish_date"],
    "size": 1
}

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "4",
        "_score": 0.5961596,
        "_source": {
          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
          "title": "Solr in Action",
          "publish_date": "2014-04-05"
        }
      }
]

 

:当术语长度大于 5 个字符时,AUTO 的模糊值等同于指定值 “2”。然则,80% 拼写错误的编辑距离为 1,以是,将模糊值设置为 1 可能会提高您的整体搜索性能。更多详细信息,请参阅Elasticsearch指南中的“排版和拼写错误”(Typos and Misspellings)

6. 通配符(Wildcard)查询

通配符查询 允许你指定匹配的模式,而不是整个术语。

  • 匹配任何字符
  • * 匹配零个或多个字符。

例如,要查找名称以字母’t’开头的所有作者的纪录:

POST /bookdb_index/book/_search
{
    "query": {
        "wildcard" : {
            "authors" : "t*"
        }
    },
    "_source": ["title", "authors"],
    "highlight": {
        "fields" : {
            "authors" : {}
        }
    }
}

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "1",
        "_score": 1,
        "_source": {
          "title": "Elasticsearch: The Definitive Guide",
          "authors": [
            "clinton gormley",
            "zachary tong"
          ]
        },
        "highlight": {
          "authors": [
            "zachary <em>tong</em>"
          ]
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "2",
        "_score": 1,
        "_source": {
          "title": "Taming Text: How to Find, Organize, and Manipulate It",
          "authors": [
            "grant ingersoll",
            "thomas morton",
            "drew farris"
          ]
        },
        "highlight": {
          "authors": [
            "<em>thomas</em> morton"
          ]
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "4",
        "_score": 1,
        "_source": {
          "title": "Solr in Action",
          "authors": [
            "trey grainger",
            "timothy potter"
          ]
        },
        "highlight": {
          "authors": [
            "<em>trey</em> grainger",
            "<em>timothy</em> potter"
          ]
        }
      }
    ] 

 

7. 正则(Regexp)查询

正则查询 让你可以使用比 通配符查询 更庞大的模式举行查询:

POST /bookdb_index/book/_search
{
    "query": {
        "regexp" : {
            "authors" : "t[a-z]*y"
        }
    },
    "_source": ["title", "authors"],
    "highlight": {
        "fields" : {
            "authors" : {}
        }
    }
}

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "4",
        "_score": 1,
        "_source": {
          "title": "Solr in Action",
          "authors": [
            "trey grainger",
            "timothy potter"
          ]
        },
        "highlight": {
          "authors": [
            "<em>trey</em> grainger",
            "<em>timothy</em> potter"
          ]
        }
      }
    ]

 

8. 短语匹配(Match Phrase)查询

短语匹配查询 要求在请求字符串中的所有查询项必须都在文档中存在,文中顺序也得和请求字符串一致,且相互相连。默认情况下,查询项之间必须慎密相连,但可以设置 slop 值来指定查询项之间可以分开多远的距离,效果仍将被看成一次乐成的匹配。

POST /bookdb_index/book/_search
{
    "query": {
        "multi_match" : {
            "query": "search engine",
            "fields": ["title", "summary"],
            "type": "phrase",
            "slop": 3
        }
    },
    "_source": [ "title", "summary", "publish_date" ]
}

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "4",
        "_score": 0.22327082,
        "_source": {
          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
          "title": "Solr in Action",
          "publish_date": "2014-04-05"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "1",
        "_score": 0.16113183,
        "_source": {
          "summary": "A distibuted real-time search and analytics engine",
          "title": "Elasticsearch: The Definitive Guide",
          "publish_date": "2015-02-07"
        }
      }
    ]

 

:在上述例子中,对于非整句类型的查询,_id 为 1 的文档一样平常会比 _id 为 4 的文档得分高,效果位置也更靠前,由于它的字段长度较短,然则对于 短语匹配类型 查询,由于查询项之间的靠近水平是一个盘算因素,因此 _id 为 4 的文档得分更高。

9. 短语前缀(Match Phrase Prefix)查询

短语前缀式查询 能够举行 即时搜索(search-as-you-type) 类型的匹配,或者说提供一个查询时的低级自动补全功效,无需以任何方式准备你的数据。和 match_phrase 查询类似,它吸收slop 参数(用来调整单词顺序和不太严酷的相对位置)和 max_expansions 参数(用来限制查询项的数目,降低对资源需求的强度)。

POST /bookdb_index/book/_search
{
    "query": {
        "match_phrase_prefix" : {
            "summary": {
                "query": "search en",
                "slop": 3,
                "max_expansions": 10
            }
        }
    },
    "_source": [ "title", "summary", "publish_date" ]
}

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "4",
        "_score": 0.5161346,
        "_source": {
          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
          "title": "Solr in Action",
          "publish_date": "2014-04-05"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "1",
        "_score": 0.37248808,
        "_source": {
          "summary": "A distibuted real-time search and analytics engine",
          "title": "Elasticsearch: The Definitive Guide",
          "publish_date": "2015-02-07"
        }
      }
    ]

 

:接纳 查询时即时搜索 具有较大的性能成本。更好的解决方案是接纳 索引时即时搜索。更多信息,请查看 自动补齐接口(Completion Suggester API)边缘分词器(Edge-Ngram filters)的用法

10. 查询字符串(Query String)

查询字符串 类型(query_string)的查询提供了一个方式,用简练的简写语法来执行 多匹配查询布尔查询提权查询模糊查询通配符查询正则查询局限查询。下面的例子中,我们在那些作者是 “grant ingersoll”“tom morton” 的某本书当中,使用查询项 “search algorithm” 举行一次模糊查询,搜索所有字段,但给 summary 的权重提升 2 倍。

POST /bookdb_index/book/_search
{
    "query": {
        "query_string" : {
            "query": "(saerch~1 algorithm~1) AND (grant ingersoll)  OR (tom morton)",
            "fields": ["_all", "summary^2"]
        }
    },
    "_source": [ "title", "summary", "authors" ],
    "highlight": {
        "fields" : {
            "summary" : {}
        }
    }
}

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "2",
        "_score": 0.14558059,
        "_source": {
          "summary": "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization",
          "title": "Taming Text: How to Find, Organize, and Manipulate It",
          "authors": [
            "grant ingersoll",
            "thomas morton",
            "drew farris"
          ]
        },
        "highlight": {
          "summary": [
            "organize text using approaches such as full-text <em>search</em>, proper name recognition, clustering, tagging, information extraction, and summarization"
          ]
        }
      }
    ]

 

11. 简朴查询字符串(Simple Query String)

简朴请求字符串 类型(simple_query_string)的查询是请求字符串类型query_string)查询的一个版本,它更适合那种仅露出给用户一个简朴搜索框的场景;由于它用 +/\|/- 划分替换了 AND/OR/NOT,而且自动抛弃了请求中无效的部门,不会在用户失足时,抛出异常。

POST /bookdb_index/book/_search
{
    "query": {
        "simple_query_string" : {
            "query": "(saerch~1 algorithm~1) + (grant ingersoll)  | (tom morton)",
            "fields": ["_all", "summary^2"]
        }
    },
    "_source": [ "title", "summary", "authors" ],
    "highlight": {
        "fields" : {
            "summary" : {}
        }
    }
}

 

12. 词条(Term)/多词条(Terms)查询

以上例子均为 full-text(全文检索) 的示例。有时我们对结构化查询更感兴趣,希望获得更准确的匹配并返回效果,词条查询多词条查询 可帮我们实现。在下面的例子中,我们要在索引中找到所有由 Manning 出书的图书。

POST /bookdb_index/book/_search
{
    "query": {
        "term" : {
            "publisher": "manning"
        }
    },
    "_source" : ["title","publish_date","publisher"]
}

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "2",
        "_score": 1.2231436,
        "_source": {
          "publisher": "manning",
          "title": "Taming Text: How to Find, Organize, and Manipulate It",
          "publish_date": "2013-01-24"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "3",
        "_score": 1.2231436,
        "_source": {
          "publisher": "manning",
          "title": "Elasticsearch in Action",
          "publish_date": "2015-12-03"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "4",
        "_score": 1.2231436,
        "_source": {
          "publisher": "manning",
          "title": "Solr in Action",
          "publish_date": "2014-04-05"
        }
      }
    ]

 

可使用词条关键字来指定多个词条,将搜索项用数组传入。

{
    "query": {
        "terms" : {
            "publisher": ["oreilly", "packt"]
        }
    }
} 

  

13. 词条(Term)查询 - 排序(Sorted)

词条查询 的效果(和其他查询效果一样)可以被容易排序,多级排序也被允许:

POST /bookdb_index/book/_search
{
    "query": {
        "term" : {
            "publisher": "manning"
        }
    },
    "_source" : ["title","publish_date","publisher"],
    "sort": [
        { "publish_date": {"order":"desc"}},
        { "title": { "order": "desc" }}
    ]
}

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "3",
        "_score": null,
        "_source": {
          "publisher": "manning",
          "title": "Elasticsearch in Action",
          "publish_date": "2015-12-03"
        },
        "sort": [
          1449100800000,
          "in"
        ]
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "4",
        "_score": null,
        "_source": {
          "publisher": "manning",
          "title": "Solr in Action",
          "publish_date": "2014-04-05"
        },
        "sort": [
          1396656000000,
          "solr"
        ]
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "2",
        "_score": null,
        "_source": {
          "publisher": "manning",
          "title": "Taming Text: How to Find, Organize, and Manipulate It",
          "publish_date": "2013-01-24"
        },
        "sort": [
          1358985600000,
          "to"
        ]
      }
    ]

 

14. 局限查询

另一个结构化查询的例子是 局限查询。在这个例子中,我们要查找 2015 年出书的书。

POST /bookdb_index/book/_search
{
    "query": {
        "range" : {
            "publish_date": {
                "gte": "2015-01-01",
                "lte": "2015-12-31"
            }
        }
    },
    "_source" : ["title","publish_date","publisher"]
}

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "1",
        "_score": 1,
        "_source": {
          "publisher": "oreilly",
          "title": "Elasticsearch: The Definitive Guide",
          "publish_date": "2015-02-07"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "3",
        "_score": 1,
        "_source": {
          "publisher": "manning",
          "title": "Elasticsearch in Action",
          "publish_date": "2015-12-03"
        }
      }
    ]

 

局限查询 用于日期、数字和字符串类型的字段。

15. 过滤(Filtered)查询

过滤查询允许你可以过滤查询效果。对于我们的例子中,要在题目或摘要中检索一些书,查询项为 Elasticsearch,但我们又想筛出那些仅有 20 个以上谈论的。

POST /bookdb_index/book/_search
{
    "query": {
        "filtered": {
            "query" : {
                "multi_match": {
                    "query": "elasticsearch",
                    "fields": ["title","summary"]
                }
            },
            "filter": {
                "range" : {
                    "num_reviews": {
                        "gte": 20
                    }
                }
            }
        }
    },
    "_source" : ["title","summary","publisher", "num_reviews"]
}

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "1",
        "_score": 0.5955761,
        "_source": {
          "summary": "A distibuted real-time search and analytics engine",
          "publisher": "oreilly",
          "num_reviews": 20,
          "title": "Elasticsearch: The Definitive Guide"
        }
      }
    ]

 

过滤查询 并不强制它作用于其上的查询必须存在。若是未指定查询,match_all 基本上会返回索引内的所有文档。现实上,过滤只在第一次运行,以削减所需的查询面积,而且,在第一次使用后过滤会被缓存,大大提高了性能。

更新过滤查询 将在 ElasticSearch 5 中移除,使用 布尔查询 替换。 下面有个例子使用 布尔查询 重写上面的例子:

POST /bookdb_index/book/_search
{
    "query": {
        "bool": {
            "must" : {
                "multi_match": {
                    "query": "elasticsearch",
                    "fields": ["title","summary"]
                }
            },
            "filter": {
                "range" : {
                    "num_reviews": {
                        "gte": 20
                    }
                }
            }
        }
    },
    "_source" : ["title","summary","publisher", "num_reviews"]
}

 

在后续的例子中,我们将会把它使用在 多重过滤 中。

16. 多重过滤(Multiple Filters)

多重过滤 可以连系 布尔查询 使用,下一个例子中,过滤查询决议只返回那些包罗至少20条谈论,且必须在 2015 年前出书,且由 O’Reilly 出书的效果。

POST /bookdb_index/book/_search
{
    "query": {
        "filtered": {
            "query" : {
                "multi_match": {
                    "query": "elasticsearch",
                    "fields": ["title","summary"]
                }
            },
            "filter": {
                "bool": {
                    "must": {
                        "range" : { "num_reviews": { "gte": 20 } }
                    },
                    "must_not": {
                        "range" : { "publish_date": { "lte": "2014-12-31" } }
                    },
                    "should": {
                        "term": { "publisher": "oreilly" }
                    }
                }
            }
        }
    },
    "_source" : ["title","summary","publisher", "num_reviews", "publish_date"]
}

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "1",
        "_score": 0.5955761,
        "_source": {
          "summary": "A distibuted real-time search and analytics engine",
          "publisher": "oreilly",
          "num_reviews": 20,
          "title": "Elasticsearch: The Definitive Guide",
          "publish_date": "2015-02-07"
        }
      }
    ] 

 

17. 作用分值: 域值(Field Value)因子

也许在某种情况下,你想把文档中的某个特定域作为盘算相关性分值的一个因素,对照典型的场景是你想凭据普及水平来提高一个文档的相关性。在我们的示例中,我们想把最受迎接的书(基于谈论数判断)的权重举行提高,可使用 field_value_factor 用以影响分值。

POST /bookdb_index/book/_search
{
    "query": {
        "function_score": {
            "query": {
                "multi_match" : {
                    "query" : "search engine",
                    "fields": ["title", "summary"]
                }
            },
            "field_value_factor": {
                "field" : "num_reviews",
                "modifier": "log1p",
                "factor" : 2
            }
        }
    },
    "_source": ["title", "summary", "publish_date", "num_reviews"]
}

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "1",
        "_score": 0.44831306,
        "_source": {
          "summary": "A distibuted real-time search and analytics engine",
          "num_reviews": 20,
          "title": "Elasticsearch: The Definitive Guide",
          "publish_date": "2015-02-07"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "4",
        "_score": 0.3718407,
        "_source": {
          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
          "num_reviews": 23,
          "title": "Solr in Action",
          "publish_date": "2014-04-05"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "3",
        "_score": 0.046479136,
        "_source": {
          "summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",
          "num_reviews": 18,
          "title": "Elasticsearch in Action",
          "publish_date": "2015-12-03"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "2",
        "_score": 0.041432835,
        "_source": {
          "summary": "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization",
          "num_reviews": 12,
          "title": "Taming Text: How to Find, Organize, and Manipulate It",
          "publish_date": "2013-01-24"
        }
      }
    ]

 

注1: 我们可能刚运行了一个通例的 multi_match (多匹配)查询,并对 num_reviews 域举行了排序,这让我们失去了评估相关性分值的利益。

注2: 有大量的附加参数可用来调整提升原始相关性分值效果的水平,好比 modifier, factor, boost_mode 等等,至于细节可在 Elasticsearch 指南中探索。

18. 作用分值: 衰变(Decay)函数

假设不想使用域值做递增提升,而你有一个理想目标值,并希望用这个加权因子来对这个离你较远的目标值举行衰减。有个典型的用途是基于经纬度、价钱或日期等数值域的提升。在如下的例子中,我们查找在2014年6月左右出书的,查询项是 search engines 的书。

POST /bookdb_index/book/_search
{
    "query": {
        "function_score": {
            "query": {
                "multi_match" : {
                    "query" : "search engine",
                    "fields": ["title", "summary"]
                }
            },
            "functions": [
                {
                    "exp": {
                        "publish_date" : {
                            "origin": "2014-06-15",
                            "offset": "7d",
                            "scale" : "30d"
                        }
                    }
                }
            ],
            "boost_mode" : "replace"
        }
    },
    "_source": ["title", "summary", "publish_date", "num_reviews"]
}

[Results]
"hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "4",
        "_score": 0.27420625,
        "_source": {
          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
          "num_reviews": 23,
          "title": "Solr in Action",
          "publish_date": "2014-04-05"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "1",
        "_score": 0.005920768,
        "_source": {
          "summary": "A distibuted real-time search and analytics engine",
          "num_reviews": 20,
          "title": "Elasticsearch: The Definitive Guide",
          "publish_date": "2015-02-07"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "2",
        "_score": 0.000011564,
        "_source": {
          "summary": "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization",
          "num_reviews": 12,
          "title": "Taming Text: How to Find, Organize, and Manipulate It",
          "publish_date": "2013-01-24"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "3",
        "_score": 0.0000059171475,
        "_source": {
          "summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",
          "num_reviews": 18,
          "title": "Elasticsearch in Action",
          "publish_date": "2015-12-03"
        }
      }
    ]

 

19. 函数分值: 剧本评分

当内置的评分函数无法知足你的需求时,还可以用 Groovy 剧本。在我们的例子中,想要指定一个剧本,能在决议把 num_reviews 的因子盘算若干之前,先将 publish_date 思量在内。由于很新的书也许不会有谈论,分值不应该被责罚。

评分剧本如下:

publish_date = doc['publish_date'].value
num_reviews = doc['num_reviews'].value

if (publish_date > Date.parse('yyyy-MM-dd', threshold).getTime()) {
  my_score = Math.log(2.5 + num_reviews)
} else {
  my_score = Math.log(1 + num_reviews)
}
return my_score

 

script_score 参数内动态挪用评分剧本:

POST /bookdb_index/book/_search
{
    "query": {
        "function_score": {
            "query": {
                "multi_match" : {
                    "query" : "search engine",
                    "fields": ["title", "summary"]
                }
            },
            "functions": [
                {
                    "script_score": {
                        "params" : {
                            "threshold": "2015-07-30"
                        },
                        "script": "publish_date = doc['publish_date'].value; num_reviews = doc['num_reviews'].value; if (publish_date > Date.parse('yyyy-MM-dd', threshold).getTime()) { return log(2.5 + num_reviews) }; return log(1 + num_reviews);"
                    }
                }
            ]
        }
    },
    "_source": ["title", "summary", "publish_date", "num_reviews"]
}

[Results]
"hits": {
    "total": 4,
    "max_score": 0.8463001,
    "hits": [
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "1",
        "_score": 0.8463001,
        "_source": {
          "summary": "A distibuted real-time search and analytics engine",
          "num_reviews": 20,
          "title": "Elasticsearch: The Definitive Guide",
          "publish_date": "2015-02-07"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "4",
        "_score": 0.7067348,
        "_source": {
          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
          "num_reviews": 23,
          "title": "Solr in Action",
          "publish_date": "2014-04-05"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "3",
        "_score": 0.08952084,
        "_source": {
          "summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",
          "num_reviews": 18,
          "title": "Elasticsearch in Action",
          "publish_date": "2015-12-03"
        }
      },
      {
        "_index": "bookdb_index",
        "_type": "book",
        "_id": "2",
        "_score": 0.07602123,
        "_source": {
          "summary": "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization",
          "num_reviews": 12,
          "title": "Taming Text: How to Find, Organize, and Manipulate It",
          "publish_date": "2013-01-24"
        }
      }
    ]
  }

 

注1: 要在 Elasticsearch 实例中使用动态剧本,必须在 config/elasticsearch.yaml 文件中启用它;也可以使用存储在 Elasticsearch 服务器上的剧本。建议看看 Elasticsearch 指南文档获取更多信息。

注2: 因 JSON 不能包罗嵌入式换行符,请使用分号来支解语句。

,

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