Search Exists API

The exists API allows to easily determine if any matching documents exist for a provided query. It can be executed across one or more indices and across one or more types. The query can either be provided using a simple query string as a parameter, or using the Query DSL defined within the request body. Here is an example:

$ curl -XGET 'http://localhost:9200/twitter/tweet/_search/exists?q=user:kimchy'

$ curl -XGET 'http://localhost:9200/twitter/tweet/_search/exists' -d '
{
    "query" : {
        "term" : { "user" : "kimchy" }
    }
}'

Both the examples above do the same thing, which is determine the existence of tweets from the twitter index for a certain user. The response body will be of the following format:

{
    "exists" : true
}

The exists API can be applied to multiple types in multiple indices.

When executing exists using the query parameter q, the query passed is a query string using Lucene query parser. There are additional parameters that can be passed:

The exists API can use the Query DSL within its body in order to express the query that should be executed. The body content can also be passed as a REST parameter named source.

HTTP GET and HTTP POST can be used to execute exists with body. Since not all clients support GET with body, POST is allowed as well.

The exists operation is broadcast across all shards. For each shard id group, a replica is chosen and executed against it. This means that replicas increase the scalability of exists. The exists operation also early terminates shard requests once the first shard reports matched document existence.

The routing value (a comma separated list of the routing values) can be specified to control which shards the exists request will be executed on.