Structure of document affect speed?

[MaVa (Marta)]

I have a question out of curiosity. Does the structure of the document have any effect on the indexing and searching speed in an index?

Would e.g.

"user": {
       "id":"123",
       "first_name":"John",
       "last_name":"Doe"
}

take longer time than

{
"user_id":"123",
"user_first_name":"John",
"user_last_name":"Doe"
}

?

In the example case I know the potential difference be miniscule, but imagine you have millions of docs with loads of nested data, would it have anything to say?

[EmaysHRT]

Unless you set up custom mappings using the nested field type, the internal representation is going to be flattened to this:

{
  "user.id": "123",
  "user.first_name": "John",
  "user.last_name": "Doe"
}

It's functionally equivalent to the document on the bottom, so there should be no difference in performance.