Delete Elasticsearch index without deleting its mappings - database

Question

How can I delete data from my elasticsearch database without deleting my index mapping?
I am Tire gem and using the delete command deletes all my mappings and run the create command once again. I want to avoid the create command from being run again and again.
Please help me out with this.

Answer 1

found it at http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/docs-delete-by-query.html
DELETE <index>/_query
{
"query" : {
"match_all": {}
}
}
You can also just delete a specific type by changing it to DELETE <index>/<type>/_query
This will delete the data and maintain the mappings, setting, etc.

Answer 2

You can use index templates, which will be applied to indices whose name matches a pattern.
That way you can simply delete an index, using the delete index api (way better than deleting all documents in it), and when you recreate the same index the matching index templates will get applied to it, so that you don't need to recreate its mappings, settings, warmers as well...
What happens is that the mappings will get deleted as they refer to the index that you deleted, but since they are stored in the index templates as well you won't need to resubmit them again when recreating the same index later on.

Answer 3

Due to the way ElasticSearch delete it's documents (by flagging the document with a bitset for deletion) it wouldn't be worthwhile to iterate through X amount of documents and flagging them for delete. I believe when you flush an indices it will free memory by removing all documents with the delete bitset flagged, being an expensive operation and slowing down the shards on which the index resides in.
Hope this helps.

Answer 4

Updating Yehosef's answer based on the latest docs (6.2 as of this post):
POST <index>/_delete_by_query
{
"query" : {
"match_all": {}
}
}

Answer 5

Deleting by query is deprecated in 1.5.3
You should use the scroll/scan API to find all matching ids and then issue a bulk request to delete them.
As documented here
curl -XGET 'localhost:9200/realestate/houses/_search?scroll=1m' -d '
{
"query": {
"match_all" : { }
},
"fields": []
}
'
and then the bulk delete (don't forget to put a new line after the last row)
curl -XPOST 'localhost:9200/_bulk' -d '
{ "delete" : { "_index" : "realestate", "_type" : "houses", "_id" : "1" } }
{ "delete" : { "_index" : "realestate", "_type" : "houses", "_id" : "2" } }
{ "delete" : { "_index" : "realestate", "_type" : "houses", "_id" : "3" } }
{ "delete" : { "_index" : "realestate", "_type" : "houses", "_id" : "4" } }
{ "delete" : { "_index" : "realestate", "_type" : "houses", "_id" : "5" } }
{ "delete" : { "_index" : "realestate", "_type" : "houses", "_id" : "6" } }
{ "delete" : { "_index" : "realestate", "_type" : "houses", "_id" : "7" } }
{ "delete" : { "_index" : "realestate", "_type" : "houses", "_id" : "8" } }
'