Multiple pre & post tags in highlighter query

Elastic Stack Elasticsearch
1

Hi
I want to highlight individual query string's match result with different pre & post tags.

  • Create Index
PUT multilang_index
{
  "mappings": {
    "dynamic_templates": [
			{
				"stripped_section_template": {
					"path_match": "STRIPPED_SECTION.*",
					"mapping": {
						"search_analyzer": "index_analyzer",
						"analyzer": "index_analyzer",
						"type": "text",
						"term_vector": "with_positions_offsets"
					}
				}
			}
		]
  },
  "settings": {
		"analysis": {
			"analyzer": {
				"index_analyzer": {
					"filter": [
						"lowercase"
					],
					"tokenizer": "standard"
				}
			}
		}
	}
}
  • Index document
POST multilang_index/_doc/1
{
  "STRIPPED_SECTION": {
    "description": "failure of heart and increase in blood pressure needs to be examined",
    "id": 1
  }
}
  • Perform search query
POST multilang_index/_search
{
  "query": {
    "bool": {
      "should": [
        {
          "multi_match": {
            "fuzziness": "AUTO", 
            "query": "blood pressure",
            "fields": [
              "STRIPPED_SECTION.*"
            ]
          }
        },
        {
          "multi_match": {
            "fuzziness": "AUTO", 
            "query": "heart failure",
            "fields": [
              "STRIPPED_SECTION.*"
            ]
          }
        },
        {
          "multi_match": {
            "fuzziness": "AUTO", 
            "query": "examine",
            "fields": [
              "STRIPPED_SECTION.*"
            ]
          }
        }
      ],
      "minimum_should_match": 1
    }
  },
  "highlight": {
    "fields": {
      "STRIPPED_SECTION.*": {
        "type": "fvh",
        "pre_tags": [
          "<em1>",
          "<em2>",
          "<em3>"
        ],
        "post_tags": [
          "</em1>",
          "</em2>",
          "</em3>"
        ]
      }
    }
  }
}
  • ACTUAL Output
"highlight" : {
          "STRIPPED_SECTION.description" : [
            "<em1>failure</em1> of <em3>heart</em3> and increase in <em1>blood</em1> <em2>pressure</em2> needs to be <em2>examined</em2>"
          ]
}

In ACTUAL Output, random tags assigned to highlighted keywords.

  • EXPECTED Output
"highlight" : {
          "STRIPPED_SECTION.description" : [
            "<em2>failure</em2> of <em2>heart</em2> and increase in <em1>blood</em1> <em1>pressure</em1> needs to be <em3>examined</em3>"
          ]
}

I am expecting each matched word from one query string should highlighted with same tag

For Ex :

  • All match result of 'heart failure' query should have same tag like failure, heart
  • All match result of 'blood pressure' query should have same tag like blood, pressure
  • All match result of 'examine' query should have same tag like examined

Is there any way to achieve above mentioned behaviour?

2

Hi Mayank,
This may be of interest

3

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