Boost field on index in Elastic - elasticsearch

Question

I'm using Elastic 1.7.3 and I would like to have a boost on some fields in a index with documents like this fictional example :
{
title: "Mickey Mouse",
content: "Mickey Mouse is a fictional ...",
related_articles: [
{"title": "Donald Duck"},
{"title": "Goofy"}
]
}
Here eg: title is really important, content too, related_articles is a bit more important. My real document have lot of fields and nested object.
I would like to give more weight to the title field than content, and more to content than related_articles.
I have seen the title^5 way, but I must use it at each query and I must (I guess) list all my fields instead of a "_all" query.
I do a lot of search but I found lot of deprecated solutions (_boost by eg).
As I used to work with Sphinx : I search something that works like the field weight option where you can give some weight to field that are really important in your index than others.

Answer 1

You're right that the _boost meta-field that you could use at the type level has been deprecated.
But you can still use the boost property when defining each field in your mapping, which will boost your field at indexing time.
Your mapping would look like this:
{
"my_type": {
"properties": {
"title": {
"type": "string", "boost": 5
},
"content": {
"type": "string", "boost": 4
},
"related_articles": {
"type": "nested",
"properties": {
"title": {
"type": "string", "boost": 3
}
}
}
}
}
}
You have to be aware, though, that it's not necessarily a good idea to boost your field at index time, because once set, you cannot change it unless you are willing to re-index all of your documents, whereas using query-time boosting achieves the same effect and can be changed more easily.