I would like to know the impact of various fields in my index on the overall storage required, to better direct efforts to optimize my index mapping. My understanding is that each field has its own set of inverted indices, so the storage used by each is distinct, but I don't see any way to retrieve that from the _stats API or other APIs.
I guess it would be possible to get this by making a set of indices with mappings each containing only one of the fields, and then look at the store stats for those, but the index I'm working with is pretty large and we don't store _source, so reindexing to separate indexes for each field is costly.
Is there any better way to get these stats?