Executing a scroll search
Pagination with a standard query works very well if you are matching documents with the 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: scroll.
Getting ready
You need an up-and-running Elasticsearch installation as we described in the Downloading and installing Elasticsearch recipe in Chapter 2, Downloading and Setup.
A Maven tool, or an IDE that natively supports it for Java programming such as Eclipse or IntelliJ IDEA, installed.
The code for this recipe is in the chapter_14/nativeclient directory and the referred class is ScrollQueryExample.
How to do it...
The search is done as in the Execute a standard search recipe. The main difference is a setScroll timeout, which allows the resulting IDs to be stored in memory for a query for a defined timeout. The steps are like those for a standard search apart from:
We import the
TimeValue...
