How can we be sure, when we index a document, that we are creating an entirely new document and not overwriting an existing one?document를 색인할 때, 기존 document를 덮어쓰는 것이 아니라, 완전히 새로운 것을 생성한다는 것을 어떻게 보장할 수 있을까?Remember that the combination of _index, _type, and _id uniquely identifies a document. So the easiest way to ensure that our document is new is by letting Elasticsearch autogenerate a new uniq..