More often than not, we have customers indexing fields in Elasticsearch “just in case” they need to be used for search. If that is the case for you, then the following techniques should prove to be valuable in helping you cut costs and focus your cluster performance on what really matters.
– Too many fields! 3 ways to prevent mapping explosion in Elasticsearch: https://www.elastic.co/blog/3-ways-to-prevent-mapping-explosion-in-elasticsearch
You can watch this video also at the source.