Dealing with concatenated words in elasticsearch

Elastic Stack Elasticsearch
1

I feel this suppose to be a very straightforward problem but for some reason I can put my head around it.

I want to build a product search engine using Elasticsearch. I have a problem when it comes to concatenated words, for example I want to search for Smart watch. I running two different queries: (1) "Smart watch" and (2) "smartwatch".

In (1) I get both results that have "smartwatch and "smart watch" in their product title. However in (2) I'm getting only products that have "smartwatch" I will not get any variation with whitespace between smart and watch:

This is my index config:

config = {
 "settings": {
    "analysis": {
      "analyzer": {
        "nGram_analyzer": {
          "type": "custom",
          "tokenizer": "whitespace",
          "char_filter":["html_strip","custom_char_filter","space_maker_2", "space_maker_3" ],
          "filter": [
            "lowercase",
            "asciifolding",
            "nGram_filter"
          ]
        },
        "whitespace_analyzer": {
          "type": "custom",
          "tokenizer": "whitespace",
          "char_filter": ["space_maker_2", "space_maker_3"
          ],
          "filter": [
            "lowercase",
            "asciifolding",
            "synonym_apply",
            "special_stopwards"
          ]
        }
      },
      "char_filter": {
        "custom_char_filter": {
          "type": "mapping",
          "mappings": [
            "$ => dollar"
          ]
        },
        "space_maker_1": {
          "type": "pattern_replace", 
          "pattern": "(?<=[a-z])(?=[A-Z])|(?<=[A-Z])(?=[a-z])",
          "replacement": " "
        },
        "space_maker_2": {
          "type": "pattern_replace",
          "pattern": "(?<=\\p{Digit})(?=\\p{Alpha})|(?<=\\p{Alpha})(?=\\p{Digit})",
          "replacement": " "
        },
        "space_maker_3": {
          "type": "pattern_replace",
          "pattern": "(?<=[a-zA-Z0-9])(?=[^a-zA-Z0-9])|(?<=[^a-zA-Z0-9])(?=[a-zA-Z0-9])",
          "replacement": " "
        }
      },
       "filter": {
        "nGram_filter": {
          "type": "edge_ngram",
          "min_gram": 2,
          "max_gram": 20,
          "token_chars": [
            "letter",
            "digit",
            "punctuation",
            "symbol"
          ]
        },
        "synonym_apply": {
            "type": "synonym",
            "lenient": "true",
            "synonyms": [ "kilo, kilogram => kg",
            "buck, dollar => usd"
            ]
          },
        "special_stopwards": {
            "type": "stop",
            "stopwords": [ "ass", "butt" ]
          }
      }
    }
  },

    "mappings": {
        "properties": {
            "brand": {
                "type": "keyword"
            },
            "category": {
                "type": "keyword"
            },
            "tags": {
                "type": "keyword"
            },
            "domain": {
                "type": "keyword"
            },
            "image": {
                "type": "text"
            },
            "purchases": {
                "type": "double"
            },
            "views": {
                "type": "double"
            },
            "price": {
                "type": "double"
            },
            "product_id": {
                "type": "text"
            },
            "product_url": {
                "type": "text"
            },
            "title": {
                "type": "text",
                "analyzer": "nGram_analyzer",
                "search_analyzer": "nGram_analyzer",
            },
            "description": {
                "type": "text"
            },
            "country": {
                "type": "integer"
            },
            "last_seen_date": {
                "type": "text"
            }
        }
    }
}

And I'm using simple match query currently only the product title.

How can I change my query or index to solve this issue? or is it even solvable?

2

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