v2.x 已经不支持 mapping 内单个字段类型的修改,也不支持 delete mapping
如果 index 内多个 type, scheme migration 基本是不可能的
是不是每个 document type 用一个单独的 index 才是正确的方式
https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping.html
Other than where documented, existing type and field mappings cannot be updated. Changing the mapping would mean invalidating already indexed documents. Instead, you should create a new index with the correct mappings and reindex your data into that index.
https://www.elastic.co/guide/en/elasticsearch/reference/2.2/breaking_20_mapping_changes.html#_types_may_no_longer_be_deleted
In 1.x it was possible to delete a type mapping, along with all of the documents of that type, using the delete mapping API. This is no longer supported, because remnants of the fields in the type could remain in the index, causing corruption later on.
Instead, if you need to delete a type mapping, you should reindex to a new index which does not contain the mapping. If you just need to delete the documents that belong to that type, then use the delete-by-query plugin instead.