Sampler Aggregation

More info about histogram aggregation is in the official elasticsearch docs

A filtering aggregation used to limit any sub aggregations' processing to a sample of the top-scoring documents. Optionally, diversity settings can be used to limit the number of matches that share a common value such as an "author".

Simple example

{
    "aggregations": {
        "sample": {
            "sampler": {
                "shard_size": 200,
                "field" : "user.id"
            },
            "aggs": {
                 "keywords": {
                     "significant_terms": {
                         "field": "text"
                     }
                 }
            }
        }
    }
}

And now the query via DSL:

$samplerAggregation = new SamplerAggregation('sample', 'user.id', 200);
$samplerAggregation->addAggregation(
    new SignificantTermsAggregation('keywords', 'text')
);

$search = new Search();
$search->addAggregation($samplerAggregation);

$queryArray = $search->toArray();