Reindexing based on returned fields without loosing the information

Hello guys,
We need to remove part of the fields from the documents to shrink the index
size.
After some googling my conclusions are:

  1. there is no much choice and we have to reindex documents.
  2. it worse to do it using scan and bulk update api's.

My questions is - what is the best way to edit document:
One way I see is to get the the _source field and edit it.
While another way I'm considering is to use the partial_fields option,
which actually looks a way more convenient to deal with.
The problem is I'm not sure that the whole information that needed to
reindex the document in the proper way will exist in the returned results. *In
other words can I use the returned fields to reindex without loosing the
information or I have to use _source? *

Thanks!!!

--
You received this message because you are subscribed to the Google Groups "elasticsearch" group.
To unsubscribe from this group and stop receiving emails from it, send an email to elasticsearch+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.