Pretty big documents are stored in the Index but with not so much of fields indexable. let's say only 5% of fields are indexed but the rest just stored in _source field.
As mentioned the document is so big and when no Source Filtering is set, it takes a lot of time to have the result (just because of IO, not search). To have records in a reasonable time we decided to use Source filter but I am not sure how expensive is it for Elasticsearch (lucenc) to apply the projection. Please let me know if it would not be a source of performance issues or we should break down the document into more than one index.
Thanks in advance