Autocomplete in elastic search - elasticsearch

Question

i am planning to make an elastic search based auto complete module for an e commerce website.i am using edge_ngram for suggestions.I am trying out this configuration.
**My index creation :**
PUT my_index
{
"settings": {
"analysis": {
"analyzer": {
"autocomplete": {
"tokenizer": "autocomplete",
"filter": [
"lowercase"
]
},
"autocomplete_search": {
"tokenizer": "lowercase"
}
},
"tokenizer": {
"autocomplete": {
"type": "edge_ngram",
"min_gram": 1,
"max_gram": 10,
"token_chars": [
"letter","digit"
]
}
}
}
},
"mappings": {
"doc": {
"properties": {
"title": {
"type": "text",
"analyzer": "autocomplete",
"search_analyzer": "autocomplete_search"
}
}
}
}
}
**Inserting Data**
PUT my_index/doc/1
{
"title": "iphone s"
}
PUT my_index/doc/9
{
"title": "iphone ka"
}
PUT my_index/doc/11
{
"title": "iphone ka t"
}
PUT my_index/doc/15
{
"title": "iphone 6"
}
PUT my_index/doc/14
{
"title": "iphone 6 16GB"
}
PUT my_index/doc/3
{
"title": "iphone k"
}
POST my_index/_refresh
POST my_index/_analyze
{
"tokenizer": "autocomplete",
"text": "iphone 6"
}
POST my_index/_analyze
{
"analyzer": "pattern",
"text": "iphone 6"
}
**Autocomplete suggestions**
When i am trying to find out closets match to iphone 6.It is not showing correct result.
GET my_index/_search
{
"query": {
"match": {
"title": {
"query": "iphone 6",
"operator": "and"
}
}
}
}
**Above query yielding :**
{
"took": 0,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 7,
"max_score": 0.28582606,
"hits": [
{
"_index": "my_index",
"_type": "doc",
"_id": "1",
"_score": 0.28582606,
"_source": {
"title": "iphone s"
}
},
{
"_index": "my_index",
"_type": "doc",
"_id": "9",
"_score": 0.25811607,
"_source": {
"title": "iphone ka"
}
},
{
"_index": "my_index",
"_type": "doc",
"_id": "14",
"_score": 0.24257512,
"_source": {
"title": "iphone 6 16GB"
}
},
{
"_index": "my_index",
"_type": "doc",
"_id": "3",
"_score": 0.19100356,
"_source": {
"title": "iphone k"
}
},
{
"_index": "my_index",
"_type": "doc",
"_id": "15",
"_score": 0.1862728,
"_source": {
"title": "iphone 6"
}
},
{
"_index": "my_index",
"_type": "doc",
"_id": "11",
"_score": 0.16358379,
"_source": {
"title": "iphone ka t"
}
},
{
"_index": "my_index",
"_type": "doc",
"_id": "2",
"_score": 0.15861572,
"_source": {
"title": "iphone 5 s"
}
}
]
}
}
But result should be :
{
"_index": "my_index",
"_type": "doc",
"_id": "15",
"_score": 1,
"_source": {
"title": "iphone 6"
}
}
Please let me know if i am missing something on this,I am new to this so not aware of any other method that may yield better results.

Answer 1

You are using autocomplete_search as your search_analyzer. If you look how your text is analyzed using search analyzer specified by you.
POST my_index/_analyze
{
"analyzer": "autocomplete_search",
"text": "iphone 6"
}
You will get
{
"tokens": [
{
"token": "iphone", ===> Only one token
"start_offset": 0,
"end_offset": 6,
"type": "word",
"position": 0
}
]
}
Since all the documents have this (iphone) token in reverse index. So all the documents are returned
In case you want to match desired results, you can use the same analyzer used while indexing.
{
"query": {
"match": {
"title": {
"query": "iphone 6",
"operator": "and",
"analyzer" : "autocomplete"
}
}
}
}