Difference between _source and fields projections

Elastic Stack Elasticsearch
1

Hi,
My question is about the performance (or other) impact of the difference
between _source and fields projection.
These 2 queries return (at least in my perspective) an equivalent result:
{"_source":{"include":["name"]}}
==> {... "_source":{"name":"blah"}}
and:
{"fields":["name"]}
==>{... "fields":{"name":"blah"}}

In cases where the _source is stored -
Is there a preference to one of the approaches?
performance/memory/functional wise?

Thanks,
Udi

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2

I would like to know the difference too

3

Generally you should prefer _source. They are different but not much
different. Fields is for loading stored fields and source is for filtering
source. The funky thing is that one can simulate the other pretty well.