I changed mapping by adding 'string' inner field of 'text' type to already existing 'amount' field of a 'double' type:
"type": "text" - new inner field
and new documents work fine, but I need to update all previously stored documents, so I could search them by that 'string' field. I tried with _update_by_query and reindexing, but nothing worked and I couldn't find solution so far.
Is it possible to somehow update all documents or do I need to re-upload all them?