Elastic search - search_after parameter

Question

I read this doc to understand \'search_after\' and have two question.

1. I\'m curious that where \"tweet#654323\" comes from. Is this one of document id or field data

Answer 1

1. As mentioned in that doc, "tweet#654323" is the _uid value of the document, which is made up of the _type and the _id of the document.

2. You need as many values in search_after as you have sort clauses and those values must be ordered the same way as in your sort clause. In "search_after": [1463538857, 5147821], it looks like you're sorting by a date field and some other id field.