Elasticsearch Nest : Fetching random documents

Question

I am trying to get random records using Elastic Search NEST client. Is there any way to do this?

Greg Marzouka · Accepted Answer · 2014-11-19 02:43:41Z

3

To compliment @pickypg's answer, here's an example of how to compose a function_score query with a random_score function in NEST:

client.Search<MyType>(s => s
    .Query(q => q
        .FunctionScore(fs => fs
            .Query(fq => fq.MatchAll())
            .RandomScore()
        )
    )
);

answered Nov 19, 2014 at 2:43

Greg Marzouka

3,3251 gold badge22 silver badges17 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Joep Beusenberg Over a year ago

It seems the API has changed. This works now:

client.Search<MyType>(s => s 	.Query(q => q 		.FunctionScore(fs => fs 			.Query(fq => fq.MatchAll()) 			.Functions(f=>f 				.RandomScore( 					Guid.NewGuid().ToString() 				) 			) 		) 	) );

Eran Peled · Accepted Answer · 2020-10-13 07:38:28Z

2

ES 7.x

NEST Way :

var result = _elastic.Search<dynamic>(s => s
        .Query(q => q
        .FunctionScore(fs => fs.Functions(f => f.RandomScore())
        .Query(fq => fq.MatchAll()))));

raw query way :

 GET index-name/_search
    "size": 1,
    "query": {
        "function_score": {
                "query" : { "match_all": {} },
               "random_score": {}
        }
    }
}

answered Oct 13, 2020 at 7:38

Eran Peled

9298 silver badges6 bronze badges

Comments

pickypg · Accepted Answer · 2014-11-18 17:10:30Z

This is more of an Elasticsearch question than one related to NEST. With that in mind, you can do this using a random_score function in Elasticsearch. random_score is one of the many function_scores available in Elasticsearch -- including scripted scores -- and it can be used to control the _score for each matching document.

Relative to Elasticsearch's REST API

curl -XGET localhost:9200/your-index/your-type/_search -d '{
  "query" : {
    "function_score": {
      "query": { "match_all": {} },
      "random_score" : { }
    }
  },
  "size" : 1
}'

You can control the seed used by the random number generator or you can create your own random function score. The current random_score implementation loads the _uid field from the index (the unique identifier), which the documentation notes can be memory intensive.

Collectives™ on Stack Overflow

Elasticsearch Nest : Fetching random documents

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related