How to search for a part of a word with ElasticSearch

user_163086 0
Viewed 153572

I've recently started using ElasticSearch and I can't seem to make it search for a part of a word.

Example: I have three documents from my couchdb indexed in ElasticSearch:

{
  "_id" : "1",
  "name" : "John Doeman",
  "function" : "Janitor"
}
{
  "_id" : "2",
  "name" : "Jane Doewoman",
  "function" : "Teacher"
}
{
  "_id" : "3",
  "name" : "Jimmy Jackal",
  "function" : "Student"
}

So now, I want to search for all documents containing "Doe"

curl http://localhost:9200/my_idx/my_type/_search?q=Doe

That doesn't return any hits. But if I search for

curl http://localhost:9200/my_idx/my_type/_search?q=Doeman

It does return one document (John Doeman).

I've tried setting different analyzers and different filters as properties of my index. I've also tried using a full blown query (for example: 

{
  "query": {
    "term": {
      "name": "Doe"
    }
  }
}

) But nothing seems to work.

How can I make ElasticSearch find both John Doeman and Jane Doewoman when I search for "Doe" ?

UPDATE

I tried to use the nGram tokenizer and filter, like Igor proposed, like this:

{
  "index": {
    "index": "my_idx",
    "type": "my_type",
    "bulk_size": "100",
    "bulk_timeout": "10ms",
    "analysis": {
      "analyzer": {
        "my_analyzer": {
          "type": "custom",
          "tokenizer": "my_ngram_tokenizer",
          "filter": [
            "my_ngram_filter"
          ]
        }
      },
      "filter": {
        "my_ngram_filter": {
          "type": "nGram",
          "min_gram": 1,
          "max_gram": 1
        }
      },
      "tokenizer": {
        "my_ngram_tokenizer": {
          "type": "nGram",
          "min_gram": 1,
          "max_gram": 1
        }
      }
    }
  }
}

The problem I'm having now is that each and every query returns ALL documents. Any pointers? ElasticSearch documentation on using nGram isn't great...

elasticsearch
11 Answers

While there are a lot of answers which focuses on solving the issue at hand but don't talk much about the various trade-off which someone needs to make before choosing a particular answer. So let me try to add a few more details on this perspective.

Partial search is now a day a very common and important feature and if not implemented properly can lead to poor user experience and bad performance, so first know your application function and non-function requirement related to this feature which I talked about in my this detailed SO answer.

Now there are various approaches, like query time, index time, completion suggester and search as you type data-types added in recent version of elasticsarch.

Now people who quickly want to just implement a solution can use below end to end working solution.

Index mapping

{
  "settings": {
    "analysis": {
      "filter": {
        "autocomplete_filter": {
          "type": "ngram",
          "min_gram": 1,
          "max_gram": 10
        }
      },
      "analyzer": {
        "autocomplete": { 
          "type": "custom",
          "tokenizer": "standard",
          "filter": [
            "lowercase",
            "autocomplete_filter"
          ]
        }
      }
    },
    "index.max_ngram_diff" : 10
  },
  "mappings": {
    "properties": {
      "title": {
        "type": "text",
        "analyzer": "autocomplete", 
        "search_analyzer": "standard" 
      }
    }
  }
}

Index given sample docs

{
  "title" : "John Doeman"
  
}

{
  "title" : "Jane Doewoman"
  
}

{
  "title" : "Jimmy Jackal"
  
}

And search query

{
    "query": {
        "match": {
            "title": "Doe"
        }
    }
}

which returns expected search results

 "hits": [
            {
                "_index": "6467067",
                "_type": "_doc",
                "_id": "1",
                "_score": 0.76718915,
                "_source": {
                    "title": "John Doeman"
                }
            },
            {
                "_index": "6467067",
                "_type": "_doc",
                "_id": "2",
                "_score": 0.76718915,
                "_source": {
                    "title": "Jane Doewoman"
                }
            }
        ]
user_40394310

you can use regexp.

{ "_id" : "1", "name" : "John Doeman" , "function" : "Janitor"}
{ "_id" : "2", "name" : "Jane Doewoman","function" : "Teacher"  }
{ "_id" : "3", "name" : "Jimmy Jackal" ,"function" : "Student"  }

if you use this query :

{
  "query": {
    "regexp": {
      "name": "J.*"
    }
  }
}

you will given all of data that their name start with "J".Consider you want to receive just the first two record that their name end with "man" so you can use this query :

{
  "query": { 
    "regexp": {
      "name": ".*man"
    }
  }
}

and if you want to receive all record that in their name exist "m" , you can use this query :

{
  "query": { 
    "regexp": {
      "name": ".*m.*"
    }
  }
}

This works for me .And I hope my answer be suitable for solve your problem.

user_95121320

I am using this and got I worked

"query": {
        "query_string" : {
            "query" : "*test*",
            "fields" : ["field1","field2"],
            "analyze_wildcard" : true,
            "allow_leading_wildcard": true
        }
    }
user_36398780

Using wilcards (*) prevent the calc of a score

user_27718840
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