The count API allows to easily execute a query and get the number of matches for that query. It can be executed across one or more indices and across one or more types. The query can be provided using the Query DSL.
import static org.elasticsearch.index.query.xcontent.FilterBuilders.*; import static org.elasticsearch.index.query.xcontent.QueryBuilders.*; CountResponse response = client.prepareCount("test") .setQuery(termQuery("_type", "type1")) .execute() .actionGet();
For more information on the count operation, check out the REST count docs.
The count API allows to set the threading model the operation will be performed when the actual execution of the API is performed on the same node (the API is executed on a shard that is allocated on the same server).
There are three threading modes.The NO_THREADS mode means that the count operation will be executed on the calling thread. The SINGLE_THREAD mode means that the count operation will be executed on a single different thread for all local shards. The THREAD_PER_SHARD mode means that the count operation will be executed on a different thread for each local shard.
The default mode is SINGLE_THREAD.