ElasticSearch and NEST: How do you purge all documents from an index?

Question

I know how to delete an entire ElasticSearch index, but how do you purge all documents from an index?

My Motivation: I'd like to have a "ReIndex" method that purges the entire contents of an index so that I can reload all documents.

ElasticSearch syntax would be helful. NEST syntax would be even better.

Beefeater

DeleteByQuery is now deprecated. Any one got the latest syntax in Nest 2 versions? – Peroneus

@Linoy.M.Kunjappan DeleteByQuery is no longer deprecated. As stated here "DBQ was originally deprecated and removed from Elasticsearch itself, then they brought it back with a new implementation." – Sequestration

Answer 1

I was looking for something similar in Nest and I thought I'd put the syntax here for anyone looking:

var node = new Uri("http://localhost:9200");
var settings = new ConnectionSettings(node);
var client = new ElasticClient(settings);

client.DeleteByQuery<ElasticsearchProject>(del => del
    .Query(q => q.QueryString(qs=>qs.Query("*")))
);

Wun

This is a generic form that requires a T to be specified. What if I want to delete form all indices and all types? – Sharper

@MathiasLykkegaardLorenzen Use dynamic instead of T. – Dynamics

Answer 2

You can use a delete by query. This will delete all documents that match * i.e. everything.

curl -XDELETE localhost:9200/<indexname>/_query?q=*

• Change localhost to the hostname that node is running on.

http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/docs-delete-by-query.html

Don't forget to optimize afterwards.

curl localhost:9200/<indexname>/_optimize

Instantaneous

Link is dead. https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-delete-by-query.html looks like a good replacement. – Sequestration

Answer 3

$ curl -XPOST localhost:9200/myindex/_optimize ....

The optimization process will clean all your softdeletes done by you by delete by query.

We are also facing a simillar problem where we deletes a lot of documents.Actually we move lot of documents from one index to other as we have sharded data by date. But as ES doesn't support moving of data from one index to other.

But optimization, is a costly operation as it consumes a lot of IO seeks. If you just want to do purge just for deletes I guess then you can utilize "only_expunge_deletes" flag to merge segments with deletes only.

http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/indices-optimize.html

Poltroonery

Answer 4

**To delete all Records -**
client.DeleteByQuery<ElasticsearchProject>(del => del
            .Query(q => q.QueryString(qs=>qs.Query("*"))
        ));
**To delete index-**
client.DeleteIndex(d => d.Index("index_name"));

Mossberg

Answer 5

Delete IndexName with ES v7.0.9. Use.AllIndices() or .Index("_all") instead .Index("IndexName") to delete all Index

await DeleteByQueryAsync<object>(q => q
          .Index("IndexName")
          .Query(rq => rq.MatchAll())
      );

Chirk