How doc_as_upsert works

[mohigup (Magicastic)]

I tried creating document (id=1) using PUT to /_update with "doc_as_upsert" : true and doc field. The response "result" attribute had value "created" and "version" attribute had value "1".

Again, I updated the same document with all attributes as before (id=1) using PUT to /_update with "doc_as_upsert" : true and doc field. The response "result" attribute had value "noop" and "version" attribute had value "1".

Now, I updated the same document with all attributes but one changed (id=1) using PUT to /_update with "doc_as_upsert" : true and doc field. The response "result" attribute had value "updated" and "version" attribute had value "2".

As far I understand, EL checks each attribute of the document in input against the document in index and returns response based on following:

case 1: If there is no match, it returns "noop"
case 2: If there is at least one difference, it returns "updated"
case 3: if the document doesn't exists, it creates a new document and returns "created"

How does EL handles the above behaviour? Is there any hashing performed to determine changes?
Can someone confirm that no indexing happens for case 1?

[Dan_Markhasin]

Update API | Elasticsearch Guide [8.11] | Elastic

By default updates that don’t change anything detect that they don’t change anything and return "result": "noop"

[mohigup (Magicastic)]

Hi Dan,

Thanks for the Reply. However, I am looking for the internal logic that is used to detect changes and if someone can confirm that there is no indexing happens for case 1.