Efficient way to reindex a big index using parent/child to ES 2.0


I've read about memory and performance improvements of parent/child handling in ES 2.0 and I want to benefit from it.
The docs advise to reindex my index that use _parent field (https://www.elastic.co/guide/en/elasticsearch/reference/2.0/breaking_20_parent_child_changes.html).

I'm looking for advice what would be the easiest/fastest way to do it?

The docs say: "The refactored and improved implementation is only active for indices created on or after version 2.0."
Is there a better way (in terms of human effort and processing time), than just to create a new index and indexing all of my data once again?

For example if I made a snaphot of my ES 1.7 index and tried to restore it, would it automatically become performant, ES 2.0 index?


Snapshot and restore won't work, it needs to be a reindex.
The official clients all have functions that should help!