virtual scroll with elasticsearch

Question

I'm using elasticsearch and kendo-ui grid. Now I'm switching from endless scroll to virtual scroll. At the moment I use the Scroll Api in elasticsearch, but can't control the range for my request.

Is there a way to get a session like in scroll, where I could send the from and size ? Or is there a better way to handle this?

Answer 1

Use the search_after parameter in your search query.

search_after can be used when you sort your documents on one or multiple fields. In the search_after parameter you set the values for the fields that should be higher for all retrieved documents.

If you have for example a numeric field document_position with values from 0 to 1000. To retrieve the documents with document_position values higher than 200 you use the following query :

{
    "query": { // your query },
    "sort": "document_position",
    "search_after": [200]
}

You can use the score value in the search after parameter, but be aware that by default the score is not necessary consistent beetween search request . The documentation presents a solution to this problem. If you use the score (or any other field which is not unique for all documents), you will also have to sort on a second field that must be unique for all documents.