doc-exports/docs/css/umn/css_01_0175.html

High-cardinality Field Histogram Aggregation

High-cardinality fields are usually used for histogram grouping and aggregation instead of single-point grouping and aggregation. For example, collecting the statistics of logs at a certain period. Assume that the following query statement exists:

POST testindex/_search?pretty
{
  "size": 0,
  "aggs": {
    "avg_score": {
      "avg": {
        "field": "score"
      },
      "aggs": {
        "groupbytime": {
          "date_histogram": {
            "field": "timestamp",
            "calendar_interval": "day"
          }
        }
      }
    }
  }
}

This query groups the field timestamp using a histogram and calculates the average score. timestamp is a typical high-cardinality field. To use the enhanced aggregation for the preceding query, set parameters as follows:

// Configure an index
"settings" : {
    "index" : {
        "search" : {
            "turbo" : {
                "enabled" : "true" // Enable optimization
            }
        },
        "sort" : { // Specify a sorting key
            "field" : [
                "timestamp"
            ]
        }
    }
}

Parent topic: Enhanced Aggregation