Modifying your index structure with the update API
In the previous chapters, we discussed how to create index mappings and index the data. But what if you already have the mappings created, and data indexed, but you want to modify the structure of the index? Of course one could say that we could just create a new index with new mappings, but that is not always a possibility, especially in a production environment. This is possible to some extent. For example, by default, if we index a document with a new field, Elasticsearch will add that field to the index structure. Let's now look at how to modify the index structure manually.
For situations where mapping changes are needed and they are not possible because of conflicts with the current index ...