Boost if result begin with the word - elasticsearch

Question

I use Elasticsearch to search with autocompletion with an ngram filter. I need to boost a result if it starts with the search keyword.
My query is simple :
"query": {
"match": {
"query": "re",
"operator": "and"
}
}
And this is my results :
Restaurants
Couture et retouches
Restauration rapide
But I want them like this :
Restaurants
Restauration rapide
Couture et retouches
How can I boost a result starting with the keyword?
In case it can helps, here is my mapping :
{
"settings": {
"analysis": {
"analyzer": {
"partialAnalyzer": {
"type": "custom",
"tokenizer": "ngram_tokenizer",
"filter": ["asciifolding", "lowercase"]
},
"searchAnalyzer": {
"type": "custom",
"tokenizer": "standard",
"filter": ["asciifolding", "lowercase"]
}
},
"tokenizer": {
"ngram_tokenizer": {
"type": "edge_ngram",
"min_gram": "1",
"max_gram": "15",
"token_chars": [ "letter", "digit" ]
}
}
}
},
"mappings": {
"place": {
"properties": {
"name": {
"type": "string",
"index_analyzer": "partialAnalyzer",
"search_analyzer": "searchAnalyzer",
"term_vector": "with_positions_offsets"
}
}
}
}
}
Regards,

Answer 1

How about this idea, not 100% sure of it as it depends on the data I think:
create a sub-field in your name field that should be analyzed with keyword analyzer (pretty much staying as is)
change the query to be a bool with shoulds
one should is the query you have now
the other should is a match with phrase_prefix on the sub-field.
The mapping:
{
"settings": {
"analysis": {
"analyzer": {
"partialAnalyzer": {
"type": "custom",
"tokenizer": "ngram_tokenizer",
"filter": [
"asciifolding",
"lowercase"
]
},
"searchAnalyzer": {
"type": "custom",
"tokenizer": "standard",
"filter": [
"asciifolding",
"lowercase"
]
},
"keyword_lowercase": {
"type": "custom",
"tokenizer": "keyword",
"filter": [
"asciifolding",
"lowercase"
]
}
},
"tokenizer": {
"ngram_tokenizer": {
"type": "edge_ngram",
"min_gram": "1",
"max_gram": "15",
"token_chars": [
"letter",
"digit"
]
}
}
}
},
"mappings": {
"place": {
"properties": {
"name": {
"type": "string",
"index_analyzer": "partialAnalyzer",
"search_analyzer": "searchAnalyzer",
"term_vector": "with_positions_offsets",
"fields": {
"as_is": {
"type": "string",
"analyzer": "keyword_lowercase"
}
}
}
}
}
}
}
The query:
{
"query": {
"bool": {
"should": [
{
"match": {
"name": {
"query": "re",
"operator": "and"
}
}
},
{
"match": {
"name.as_is": {
"query": "re",
"type": "phrase_prefix"
}
}
}
]
}
}
}