normalizer(归一化)

原文链接 : https://www.elastic.co/guide/en/elasticsearch/reference/current/normalizer.html

译文链接 : normalizer(归一化)

贡献者 : 程威，ApacheCN，Apache中文网

keyword** fields（关键字字段） 的 normalizer（归一化）属性与 analyzer（分析器）类似,只不过它保证 analysis chain（分析链）生成单一的 token **（词元）.

normalizer（归一化）应用于索引 keyword（关键字）之前,以及诸如在 [match](https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-match-query.html) query(匹配查询),查询解析器搜索 keyword** fields**（关键字字段）的时候.

  1. curl -XPUT 'localhost:9200/index?pretty' -H 'Content-Type: application/json' -d'
  2. {
  3.   "settings": {
  4.     "analysis": {
  5.       "normalizer": {
  6.         "my_normalizer": {
  7.           "type": "custom",
  8.           "char_filter": [],
  9.           "filter": ["lowercase", "asciifolding"]
  10.         }
  11.       }
  12.     }
  13.   },
  14.   "mappings": {
  15.     "type": {
  16.       "properties": {
  17.         "foo": {
  18.           "type": "keyword",
  19.           "normalizer": "my_normalizer"
  20.         }
  21.       }
  22.     }
  23.   }
  24. }
  25. '
  26. curl -XPUT 'localhost:9200/index/type/1?pretty' -H 'Content-Type: application/json' -d'
  27. {
  28.   "foo": "BÀR"
  29. }
  30. '
  31. curl -XPUT 'localhost:9200/index/type/2?pretty' -H 'Content-Type: application/json' -d'
  32. {
  33.   "foo": "bar"
  34. }
  35. '
  36. curl -XPUT 'localhost:9200/index/type/3?pretty' -H 'Content-Type: application/json' -d'
  37. {
  38.   "foo": "baz"
  39. }
  40. '
  41. curl -XPOST 'localhost:9200/index/_refresh?pretty'
  42. curl -XGET 'localhost:9200/index/_search?pretty' -H 'Content-Type: application/json' -d'
  43. {
  44.   "query": {
  45.     "match": {
  46.       "foo": "BAR"
  47.     }
  48.   }
  49. }
  50. '

上述查询与 documents（文档） 1 和 2 相匹配,这是因为在索引和查询的时候都将 BAR转换为了 bar.

  1. {
  2.   "took": $body.took,
  3.   "timed_out": false,
  4.   "_shards": {
  5.     "total": 5,
  6.     "successful": 5,
  7.     "failed": 0
  8.   },
  9.   "hits": {
  10.     "total": 2,
  11.     "max_score": 0.2876821,
  12.     "hits": [
  13.       {
  14.         "_index": "index",
  15.         "_type": "type",
  16.         "_id": "2",
  17.         "_score": 0.2876821,
  18.         "_source": {
  19.           "foo": "bar"
  20.         }
  21.       },
  22.       {
  23.         "_index": "index",
  24.         "_type": "type",
  25.         "_id": "1",
  26.         "_score": 0.2876821,
  27.         "_source": {
  28.           "foo": "BÀR"
  29.         }
  30.       }
  31.     ]
  32.   }
  33. }

此外,keywords 在索引之前转换意味着聚合返回 normalised values（归一化的值）:

  1. curl -XGET 'localhost:9200/index/_search?pretty' -H 'Content-Type: application/json' -d'
  2. {
  3.   "size": 0,
  4.   "aggs": {
  5.     "foo_terms": {
  6.       "terms": {
  7.         "field": "foo"
  8.       }
  9.     }
  10.   }
  11. }
  12. '

返回

  1. {
  2.   "took": 43,
  3.   "timed_out": false,
  4.   "_shards": {
  5.     "total": 5,
  6.     "successful": 5,
  7.     "failed": 0
  8.   },
  9.   "hits": {
  10.     "total": 3,
  11.     "max_score": 0.0,
  12.     "hits": []
  13.   },
  14.   "aggregations": {
  15.     "foo_terms": {
  16.       "doc_count_error_upper_bound": 0,
  17.       "sum_other_doc_count": 0,
  18.       "buckets": [
  19.         {
  20.           "key": "bar",
  21.           "doc_count": 2
  22.         },
  23.         {
  24.           "key": "baz",
  25.           "doc_count": 1
  26.         }
  27.       ]
  28.     }
  29.   }
  30. }