What's the different between index and update document in elasticsearch?

Question

As we know when we update an existed document the Elasticsearch engine will reindex the document and mark the previous document deleted. But for the restful API, it's same. So I guess the ElasticSearch will analysis the document whether exist by the unique document ID and then update or index.

So my question is, we don't need to care the index or update functionality, because both restful API and Java Client are PUT the same endpoint, Am I right?

Answer 1

The most difference for PUT and POST document in Elasticsearch :

1. POST will create a new document with a new unique ID .

2. PUT will update the current document without change ID .

so if your ID is important to you like for some context , you should use PUT to update a document to keep this ID .