curl http://localhost:9200/index/type/_search?pretty=true -d '
{
    "query" : {
        "match_all" : {}
    },
    "stored_fields": []
}
'

{
  "took" : 7,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "failed" : 0
  },
  "hits" : {
    "total" : 4,
    "max_score" : 1.0,
    "hits" : [ {
      "_index" : "index",
      "_type" : "type",
      "_id" : "36",
      "_score" : 1.0
    }, {
      "_index" : "index",
      "_type" : "type",
      "_id" : "38",
      "_score" : 1.0
    }, {
      "_index" : "index",
      "_type" : "type",
      "_id" : "39",
      "_score" : 1.0
    }, {
      "_index" : "index",
      "_type" : "type",
      "_id" : "34",
      "_score" : 1.0
    } ]
  }
}

curl http://localhost:9200/index/type/_search?pretty=true -d '
{
    "query" : {
        "match_all" : {}
    },
    "fields": ["document_field_to_be_returned"]
}
'

from elasticsearch import Elasticsearch
from elasticsearch_dsl import Search

es = Elasticsearch()
s = Search(using=es, index=ES_INDEX, doc_type=DOC_TYPE)

s = s.fields([])  # only get ids, otherwise `fields` takes a list of field names
ids = [h.meta.id for h in s.scan()]

GET http://localhost:9200/my_index/my_doc/_search?search_type=scan&scroll=5m [status:200 request:0.003s]
GET http://localhost:9200/_search/scroll?scroll=5m [status:200 request:0.005s]
GET http://localhost:9200/_search/scroll?scroll=5m [status:200 request:0.005s]
GET http://localhost:9200/_search/scroll?scroll=5m [status:200 request:0.003s]
GET http://localhost:9200/_search/scroll?scroll=5m [status:200 request:0.005s]
...

curl 'http://localhost:9200/index/type/_search?pretty=true&fields='

GET /_search
{
    "_source": false,
    "query" : {
        "term" : { "user" : "kimchy" }
    }
}

from elasticsearch import Elasticsearch
from elasticsearch.helpers import scan
es = Elasticsearch()
for dobj in scan(es,
                 query={"query": {"match_all": {}}, "fields" : []},
                 index="your-index-name", doc_type="your-doc-type"):
        print dobj["_id"],

import elasticsearch
es = elasticsearch.Elasticsearch()

res = es.search(
    index=your_index,
    body={"query": {"match_all": {}}, "size": 30000, "fields": ["_id"]})

ids = [d['_id'] for d in res['hits']['hits']]

from elasticsearch import Elasticsearch,helpers
es = Elasticsearch(hosts=[YOUR_ES_HOST])
a=helpers.scan(es,query={"query":{"match_all": {}}},scroll='1m',index=INDEX_NAME)#like others so far

IDs=[aa['_id'] for aa in a]

Url -> http://localhost:9200/<index>/<type>/_query
http method -> DELETE
Query -> {"query": {"match_all": {}}, "size": 30000, "fields": ["_id"]})