Elasticsearch：具有快速矢量荧光笔的多个 pre_tags/post_tags

Question

该文档包含以下关于 pre_tags/post_tags 设置的神秘评论，该设置能够包含一对以上的 pre-/post-tags：

使用快速矢量荧光笔可以有更多标签，并且 “重要性”是有序的。

有谁知道这句话的确切含义是什么？

Answer 1

花了一些时间，但通过使用 ES 1.7 和 _head 插件尝试不同的查询，我能够弄清楚多个 pre 和 post 标记如何影响突出显示。

使用快速矢量荧光笔，您可以按“重要性”的顺序指定标签，这似乎意味着它们的顺序和搜索词的顺序应该匹配。使用多个 pre 或 post 标记来达到任何效果都需要查询中的多个字段。

给定索引

{
 myindex: {
  mappings: {
   corpdocument: {
    properties: {
     createddate: {
      type: "date",
      format: "dateOptionalTime"
     },
     docbody: {
      type: "string",
      analyzer: "text_analyzer",
      fields: {
       exact: {
        type: "string",
        analyzer: "text_analyzer_exact"
       }
      }
     },
     modifieddate: {
      type: "date",
      format: "dateOptionalTime"
     },
     title: {
      type: "string"
     }
    }
   }
  }
 }
}

和搜索

POST locahost:9200/myindex/corpdocument/_search
{
 "highlight": {
  "pre_tags": ["|primary-highlight|",
  "|secondary-highlight|",
  "post_tags": ["|/primaryh-highlight|",
  "|/secondary-highlight|",
  "fields": {
   "docbody.exact": {
    "fragment_size": 150,
    "number_of_fragments": 3
   }
  }
 },
 "_source": {
  "exclude": ["docbody"]
 },
 "query": {
  "bool": {
   "should": [{
    "match": {
     "docbody.exact": {
      "query": "foo"
     }
    }
   },
   {
    "match": {
     "docbody.exact": {
      "query": "bar"
     }
    }
   }
  }
 }
}

你可以得到这样的结果

{
 "took": 14,
 "timed_out": false,
 "_shards": {
  "total": 5,
  "successful": 5,
  "failed": 0
 },
 "hits": {
  "total": 97,
  "max_score": 0.48895144,
  "hits": [{
   "_index": "myindex",
   "_type": "corpdocument",
   "_id": "XFxxZWR0ZXN0ZG9jc1xTYW5kYm94XFNhbmRib3hBbGxcRGV4dGVyX2xpdFw3NS5kb2M=",
   "_score": 0.48895144,
   "_source": {
    "createddate": "2010-11-02T00:00:00-05:00",
    "modifieddate": "2007-09-04T00:00:00-05:00",
    "_id": "XFxxZWR0ZXN0ZG9jc1xTYW5kYm94XFNhbmRib3hBbGxcRGV4dGVyX2xpdFw3NS5kb2M="
   },
   "highlight": {
    "docbody.exact": ["Lorem ipsum dolor sit amet, consectetur adipiscing elit |primary-highlight|foo|/primary-highlight|Lorem ipsum dolor sit amet, consectetur adipiscing elit",
    "Lorem ipsum dolor sit amet, consectetur adipiscing elit |secondary-highlight|bar|/secondary-highlight|TOTHE|primary-highlight|foo</span>|/primary-highlight|Lorem ipsum dolor sit amet, consectetur adipiscing elit",
    "Lorem ipsum dolor sit amet, consectetur adipiscing elit |secondary-highlight|bar|/secondary-highlight| Lorem ipsum dolor sit amet, consectetur adipiscing elit |primary-highlight|Chief|/primary-highlight| Lorem ipsum dolor sit amet, consectetur adipiscing elit"]
   }
  },
  ...
  ]
 }
}

哪个标签包含哪个命中取决于标签和搜索词的顺序。切换“foo”和“bar”的顺序，而其他所有内容都保持不变，这将导致 bar 被包裹在主标签中，而 foo 被包裹在辅助标签中。

从一些使用带有 2 个标签的 3 个搜索词的初始实验来看，似乎第三个词被包裹在第一个标签而不是第二个标签中。添加第三个标签可以解决这个问题，但需要将第二个标签复制 n 次才能覆盖所有搜索词。

"highlight": {
 "pre_tags": ["|primary-highlight|",
 "|secondary-highlight|",
 "|secondary-highlight|",
 "post_tags": ["|/primaryh-highlight|",
 "|/secondary-highlight|",
 "|/secondary-highlight|",
 "fields": {
  "docbody.exact": {
   "fragment_size": 150,
   "number_of_fragments": 3
  }
 }
},
..."query": {
 "bool": {
  "should": [{
   "match": {
    "docbody.exact": {
     "query": "foo"
    }
   }
  },
  {
   "match": {
    "docbody.exact": {
     "query": "bar"
    }
   }
  },
  {
   "match": {
    "docbody.exact": {
     "query": "baz"
    }
   }
  }
 }
}