Executing a scroll/scan search

Pagination with a standard query works very well if you are matching documents that do not change too often; otherwise, doing pagination with live data returns unpredictable results. To bypass this problem, ElasticSearch provides an extra parameter in the query called scroll.

Getting ready

You will need a working ElasticSearch cluster and a working copy of Maven.

The code of this recipe is in chapter_10/nativeclient in the code bundle, present on Packt's website and on GitHub (https://github.com/aparo/elasticsearch-cookbook-second-edition). The referred class is ScrollScanQueryExample.

How to do it...

The search is done in the same way as in the previous recipe. The main difference is a setScroll timeout that allows storing the result's ids for a query for a defined timeout in memory.

We can change the code of the previous recipe to use scroll in the following way:

import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.action.search...