What are the limitations of array size in elastic search?

[jalaj (Jalaj Kumar)]

I have document which can have a tag array.

{
   "name" :"User 1",
   "friends":["user2","user3","user4"]
}

What are the performance implications of having several elements on friends Array on insertion , retrieval etc.

Also , when a new element is appended to an array of million elements in ES, how does it impact overall perf. Is the entire array replicated to replica shard or only delta ?

I could not find implications of array size in documentation.

[jpountz (Adrien Grand)]

There is no hard limit but it's definitely recommended to keep those arrays "reasonable". When performing an update, Elasticsearch needs to fetch the entire doc, apply the update, then index the updated document and replicate the entire updated document to the replica, so very large arrays would come with a performance penalty indeed.

[senthil_mail_in (Senthil B)]

@jpountz Is there rough number to design the array size optimize? Specifically in search