How to retrieve all document ids (_id) in a specific index

Question

I am trying to retrieve all documents in an index, while getting only the _id field back.

Basically I want to retrieve all the document ids I have.

While using:

{
   "query": {
       "match_all": {}
   },
   "fields": []
}

The hits I get contain: "_index", "_type", "_id" , "_score", "_source" which is way more then I need.

Edit(Answer): So my problem was that I used KOPF to run the queries, and the results were not accurate (got the _source and some more..)! When using curl I got the correct results!

So the above query actually achieved what I needed! You can also use:

{
   "query": {
      "match_all": {}
   },
   "_source": false,
}

or

{
   "query": {
      "match_all": {}
   },
   "fields": ["_id"]
}

Answer 1

For elasticsearch, only can specific _source fields by using fields array.

_index, _type, _id, _score must will be returned by elasticsearch.

there is no way to remove them from response.

Answer 2

I am assuming your _id is of your document in index not of index itself.

In new version of elastic search, "_source" is used for retrieving selected fields of your es document because _source fields contains everything you need in elastic search for a es record.

Example:

Let's say index name is "movies" and type is "movie" and you want to retrieve the movieName and movieTitle of all elastic search records.

curl -XGET 'http://localhost:9200/movies/movie/_search?pretty=true' -d '
{ 
    "query" : { 
        "match_all" : {} 
    },
    "_source": ["movieName","movieTitle"]
}'

OR http://localhost:9200/movies/movie/_search?pretty=true&_source=movieName,movieTitle

By default it return 10 results. For getting n number of records then put &size=n in url