Efficient way to retrieve all _ids in ElasticSearch

Question

What is the fastest way to get all _ids of a certain index from ElasticSearch? Is it possible by using a simple query? One of my index has around 20,000 documents.

Answer 1

Elaborating on the 2 answers by @Robert-Lujo and @Aleck-Landgraf (someone with the permissions can gladly move this to a comment): if you do not want to print but get everything inside a list from the returned generator, here is what I use:

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]