Understanding Query-DSL parameters

• query: The query object contains all the queries that need to be passed to Elasticsearch. For example, the query to find all the documents that belong to a search category can written as follows:

  GET index_name/doc_type/_search
  {
    "query": {
      "query_string": {
   "default_field": "category",
        "query": "search"
      }
    }
  }

• from and size: These parameters control the pagination and the result size to be returned after querying. The from parameter is used to specify the starting point from which document the results will be returned. It defaults to 0. The size parameter, which defaults to 10, specifies how many top documents will be returned from the total matched documents in a corpus.

• _source: This is an optional parameter that takes field names in an array format, which are to be returned in the query results. It by default returns all the fields stored inside the _source field. If you do not want to return any field, you can specify _source: false...