How to Perform Elasticsearch aggregation without returning hits array

When performing data queries with Elasticsearch, we may only be interested in the aggregation results and not need the document list returned by the query. In such cases, setting the size parameter to 0 prevents the return of the hits array, reducing unnecessary data transfer and improving query efficiency.

Here is a specific example demonstrating how to execute an aggregation query in Elasticsearch without returning any hits:

json
GET /your-index/_search
{
  "size": 0,  # Set size to 0 to avoid returning hits
  "aggs": {
    "your_aggregation_name": {
      "terms": {
        "field": "your_field_name"
      }
    }
  }
}

In this example, the terms aggregation is used to aggregate on the your_field_name field. Here, the "size": 0 is key, as it instructs Elasticsearch not to return the matching document list but only the aggregation results.

By doing this, we can effectively optimize query performance, especially when dealing with large volumes of data. This method is highly valuable in practical applications, such as market analysis or log analysis, where statistical analysis of data is required without viewing individual documents. This approach becomes particularly important in such scenarios.