Elasticsearch multi fields multi words match - elasticsearch

Question

I'm looking to implement an auto-complete like feature on my app with elasticsearch.
Let's say my input is "ronan f", I want elastic to return all elements where "ronan" or "f" is contained in last name or first name. I expect elasticsearch to sort the result by rank, so the element which is the closest to what I search should be on top.
I tried multiple requests but none of them results as expected.
For example :
{
"query": {
"bool": {
"must_not": [
{
"match": {
"email": "*#guest.booking.com"
}
}
],
"should": [
{
"match": {
"lastname": "ronan"
}
},
{
"match": {
"firstname": "ronan"
}
},
{
"match": {
"lastname": "f"
}
},
{
"match": {
"firstname": "f"
}
}
],
"minimum_should_match" : 1
}
},
"sort": [
"_score"
],
"from": 0,
"size": 30
}
With this request the ranks seams a bit odds, for example :
"_index": "clients",
"_type": "client",
"_id": "4369",
"_score": 20.680058,
"_source": {
"firstname": "F",
"lastname": "F"
}
is on top of :
"_index": "clients",
"_type": "client",
"_id": "212360",
_score": 9.230003,
"_source": {
"firstname": "Ronan",
"lastname": "Fily"
}
For me the second result should have a better rank than the first.
Can someone show me how can I achieve the result I want ?
For info, I can't use Completion Suggester functionality of elasticsearch because I can't access the configuration of the database (so no indexes).

Answer 1

Ok as you can reindex your data i join a "start with" anylyzer. It will work caseless & on text field (i thinck first name and last name can have multi words on it).
Delete / create a new index using mappings.
define your analyzer (PUT my_index)
{
"settings": {:
"filter": {
"name_ngrams": {
"max_gram": "20",
"type": "edgeNGram",
"min_gram": "1",
"side": "front"
}
},
"analyzer": {
"partial_name": {
"type": "custom",
"filter": [
"lowercase"
,
"name_ngrams"
,
"standard"
,
"asciifolding"
],
"tokenizer": "standard"
},
"full_name": {
"type": "custom",
"filter": [
"standard"
,
"lowercase"
,
"asciifolding"
],
"tokenizer": "standard"
}
}
post _mappings using this for your fields:
"lastname": {
"type": "text",
"analyzer": "partial_name",
"search_analyzer": "full_name"
},
"firstname": {
"type": "text",
"analyzer": "partial_name",
"search_analyzer": "full_name"
}
if this is not clear and elasticsearch documentation couldnot help you dont hesite to ask us.