Executing a scrolling query
Every time a query is executed, the results are calculated and returned to the user. In Elasticsearch, there is not a deterministic order for records: pagination on a big block of values can bring inconsistency between results due to added and deleted documents and also documents with the same score. The scrolling query tries to resolve this kind of problem, giving a special cursor that allows the user to uniquely iterate all the documents.
Getting ready
You will need an up-and-running Elasticsearch installation as used in the Downloading and installing Elasticsearch recipe in Chapter 2, Downloading and Setup.
To execute curl via a command line, you need to install curl for your operating system.
To correctly execute the following commands, you will need an index populated with the chapter_05/populate_query.sh script available in the online code.
How to do it...
In order to execute a scrolling query, we will perform the following steps:
From the command line, we can...
