ES highlight測試

標籤：

Lucene提供3種高亮功能：highlighter, fast-vector-highlighter or postings-highlighter.

• highlighter: 最基本的、預設的高亮器。需要對查詢的_source進行二次Reanalyzed，速度在3種高亮器裡最慢，但不需要額外儲存index。
• postings-highighlighter: setting中需要配置"index_options" : "offsets",postings優缺點。速度中等，但是在phrase（短語查詢） query結合的查詢中，會把查詢短語的每個詞單獨高亮顯示。
• fast-vector-highligh: setting中需要配置"term_vector" : "with_positions_offsets"，速度最快，但是佔用儲存空間最大。典型空間換速度。

測試

• mapping

  curl -XPUT ‘localhost:9200/hl-test‘ -d ‘{
  "settings": {
    "index": {
      "number_of_shards": 2,
      "number_of_replicas": 0
    }
  },
  "mappings": {
    "tm": {
         "properties": {
              "content1": {
                "type": "string",
                "analyzer" : "default",
                "store": "yes",
                "term_vector" : "with_positions_offsets" 
            },
              "content2": {
              "type": "string",
              "analyzer" : "default",
              "store": "yes",
              "index_options" : "offsets"
            },
            "content3": {
                "type": "string",
                "store": "yes",
                   "analyzer" : "default"
            },
            "content4": {
                "type": "string",
                "store": "yes",
                   "index": "not_analyzed"
            }
         }
    }
  }
  }‘

  note

  offsets
  Store docs, freqs, positions, and the start and end character offsets of each term in the original string. This information is used by the postings >highlighter but is disabled by default.
  來源： https://www.elastic.co/guide/en/elasticsearch/guide/current/stopwords-phrases.html#index-options

• 測試資料
  curl -XPUT ‘http://localhost:9200/hl-test/tm/1‘ -d ‘{ "content1": "In the above case, the content field will be highlighted for each search hit (there will be another element in each search hit, called highlight, which includes the highlighted fields and the highlighted fragments)."}‘

• Query DSL

  {
  "query": {
    "term": {
      "content1": "the"
    }
  },
  "highlight": {
    "pre_tags": [
      "<tag1>"
    ],
    "post_tags": [
      "</tag1>"
    ],
    "fields": {
      "content1": {
        "type": "fvh",
        "fragment_size": 30,
        "number_of_fragments": 1,
        "force_source": true,
        "order": "score",
        "fragment_offset": 3,
        "no_match_size": 2
      },
      "content2": {
        "fragment_size": 250,
        "number_of_fragments": 0
      },
      "content3": {
        "fragment_size": 250,
        "number_of_fragments": 3,
        "force_source": true
      }
    }
  }
  }

來自為知筆記(Wiz)

ES highlight測試