The flush API allows to flush one or more indices through an API. The flush process of an index basically frees memory from the index by flushing data to the index storage and clearing the internal transaction log. By default, ElasticSearch uses memory heuristics in order to automatically trigger flush operations as required in order to clear memory.

$ curl -XPOST 'http://localhost:9200/twitter/_flush'

Multi Indexedit

The flush API can be applied to more than one index with a single call, or even on _all the indices.

$ curl -XPOST 'http://localhost:9200/kimchy,elasticsearch/_flush'

$ curl -XPOST 'http://localhost:9200/_flush'