ElasticSearch n-gram tokenfilter not finding partial words

Question

I have been playing around with ElasticSearch for a new project of mine. I have set the default analyzers to use the ngram tokenfilter. This is my elasticsearch.yml file:

index:
analysis:
    analyzer:
        default_index:
            tokenizer: standard
            filter: [standard, stop, mynGram]
        default_search:
            tokenizer: standard
            filter: [standard, stop]

    filter:
        mynGram:
            type: nGram
            min_gram: 1
            max_gram: 10

I created a new index and added the following document to it:

$ curl -XPUT http://localhost:9200/test/newtype/3 -d '{"text": "one two three four five six"}'
{"ok":true,"_index":"test","_type":"newtype","_id":"3"}

However, when I search using the query text:hree or text:ive or any other partial terms, ElasticSearch does not return this document. It returns the document only when I search for the exact term (like text:two).

I have also tried changing the config file such that default_search also uses the ngram token filter, but the result was the same. What am I doing wrong here and how do I correct it?

Answer 1

Not sure about the default_* settings. But applying a mapping that specifies index_analyzer and search_analyzer works:

curl -XDELETE localhost:9200/twitter
curl -XPOST localhost:9200/twitter -d '
{"index": 
  { "number_of_shards": 1,
    "analysis": {
       "filter": {
                  "mynGram" : {"type": "nGram", "min_gram": 2, "max_gram": 10}
                 },
       "analyzer": { "a1" : {
                    "type":"custom",
                    "tokenizer": "standard",
                    "filter": ["lowercase", "mynGram"]
                    }
                  } 
     }
  }
}
}'

curl -XPUT localhost:9200/twitter/tweet/_mapping -d '{
    "tweet" : {
        "index_analyzer" : "a1",
        "search_analyzer" : "standard", 
        "date_formats" : ["yyyy-MM-dd", "dd-MM-yyyy"],
        "properties" : {
            "user": {"type":"string", "analyzer":"standard"},
            "message" : {"type" : "string" }
        }
    }}'

curl -XPUT 'http://localhost:9200/twitter/tweet/1' -d '{
    "user" : "kimchy",
    "post_date" : "2009-11-15T14:12:12",
    "message" : "trying out Elastic Search"
}'

curl -XGET localhost:9200/twitter/_search?q=ear
curl -XGET localhost:9200/twitter/_search?q=sea

curl -XGET localhost:9200/twitter/_mapping