Different boosting for the same field in different types in Elasticsearch 2.x with multi_match query - elasticsearch

Question

I am trying to do the following as described in the documentation (which is maybe outdated at present date).
https://www.elastic.co/guide/en/elasticsearch/guide/current/mapping.html
I will adapt the scenario described there to what I want to achieve.
Imagine that we have two types in our index: blog_t1 for blog posts
about Topic 1, and blog_t2 for blog posts about Topic 2. Both types
have a title field.
Then, I want to apply query boosting to the title field for blog_t1
only.
In previous versions of Elasticsearch, you could reference the field
from the type by using blog_t1.title and blog_t2.title. So boosting
one of them was as simple as blog_t1.title^2.
But since Elasticsearch 2.x, some old support for types have been removed (for good reasons, like removing ambiguity). Those changes are described here.
https://www.elastic.co/guide/en/elasticsearch/reference/current/breaking_20_mapping_changes.html
So my question is, how can I do that boosting for the title, just for the type blog_t1, and not blog_t2, with Elasticsearch 2.x, in a multi_match query?
The query would be something like this, but this obviously does not work as type.field is not a thing anymore.
GET /my_index/_search
{
"query": {
"multi_match": {
"query": "Hello World",
"fields": [
"blog_t1.title^2",
"blog_*.title",
"author",
"content"
]
}
}
}
FYI, the only solution I found so far is to give the titles different names, like title_boosted for blog_t1 and just title for the others, which is problematic when making use of the information, as I can no longer use the "title" as a unique thing.
Thanks.

Answer 1

What about adding another "optional" constraint for the document type so docs matching it have more score (you can tune it with boosting) like:
{
"query" : {
"bool" :
{
"must" :
[
{"match" : {"title" : "Hello world"}}
],
"should" :
[
{"match" : {"_type" : "blog_t1"}}
]
}
}
}
Or with score functions:
{
"query": {
"function_score": {
"query": {
"match": {
"title": "Hello world"
}
},
"boost_mode": "multiply",
"functions": [
{
"filter": {
"term": {
"_type": "blog_t1"
}
},
"weight": 2
},
{
"filter": {
"term": {
"_type": "blog_t2"
}
},
"weight": 3
}
]
}
}
}