I'm looking at this doc: https://www.elastic.co/guide/en/elasticsearch/reference/5.6/search-request-scroll.html
searchrequest returns a single “page” of results, the
scrollAPI can be used to retrieve large numbers of results (or even all results) from a single search request, in much the same way as you would use a cursor on a traditional database.
Scrolling is not intended for real time user requests, but rather for processing large amounts of data, e.g. in order to reindex the contents of one index into a new index with a different configuration.
It says scroll timeout can be changed for reindexing a lot of data. But I don't see any example showing how to change this param using Reindex API - I guess is the only way to "reindex" an index right ?