CODEWITHSUNDEEP
elasticsearch
Fei
Fei

Reputation: 495

ElasticSearch edgeNGram

I have the following settings and analyzer:

put /tests
{
"settings": {
    "analysis": {
         "analyzer": {
             "standardWithEdgeNGram": {
                 "tokenizer": "standard",
                 "filter": ["lowercase", "edgeNGram"]
             }
         },
         "tokenizer": {
             "standard": {
                 "type": "standard"
             }
         },
         "filter": {
             "lowercase": {
                "type": "lowercase"
            },
            "edgeNGram": {
                "type": "edgeNGram",
                "min_gram": 2,
                "max_gram": 15,
                "token_chars": ["letter", "digit"]
            }
        }
    }
},
"mappings": {
    "test": {
        "_all": {
            "analyzer": "standardWithEdgeNGram"
        },
        "properties": {
            "Name": {
                "type": "string",
                "analyzer": "standardWithEdgeNGram"
            }
        }
   }
}
}

And I posted the following data into it:

POST /tests/test
{
    "Name": "JACKSON v. FRENKEL"
}

And here is my query:

GET /tests/test/_search
{
    "query": {
        "match": {
           "Name": "jax"
        }
    }
}

And I got this result:

{
    "took": 2,
    "timed_out": false,
    "_shards": {
    "total": 1,
    "successful": 1,
    "failed": 0
},
"hits": {
    "total": 1,
    "max_score": 0.19178301,
    "hits": [
        {
            "_index": "tests",
            "_type": "test",
            "_id": "lfOxb_5bS86_CMumo_ZLoA",
            "_score": 0.19178301,
            "_source": {
                "Name": "JACKSON v. FRENKEL"
            }
        }
    ]
}
}

Can someone explain to me that there is no "jax" anywhere in the "Name", and it still gets the match?

Thanks in advance

Upvotes: 2

Views: 4034

Answers (2)

Venkata Naresh
Venkata Naresh

Reputation: 366

In ES 1.3.2 the below query gave an error

GET /tests/test/_search
{
    "query": {
    "match": {
       "Name": "jax",
       "analyzer" : "keyword"
       }
  }
}

Error : query parsed in simplified form, with direct field name, but included more options than just the field name, possibly use its 'options' form, with 'query' element?]; }] status: 400

I fixed the issue as below:

{
   "query": {
       "query_string": {
            "fields": [
            "Name"
             ],
        "query": "jax",
            "analyzer": "simple"
        }
    }
}

Upvotes: 1

Paul Bellora
Paul Bellora

Reputation: 55233

A match query performs analysis on its given value. By default, "jax" is being analyzed with standardWithEdgeNGram, which includes n-gram analysis permuting it into ["ja", "ax"], the first of which matches the "ja" from the analyzed "JACKSON v. FRENKEL".

If you don't want this behavior you can specify a different analyzer to match, using the analyzer field, for example keyword:

GET /tests/test/_search
{
    "query": {
        "match": {
           "Name": "jax",
           "analyzer" : "keyword"
        }
    }
}

Upvotes: 4

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