Max bucket aggregation

Max bucket aggregation

A sibling pipeline aggregation which identifies the bucket(s) with the maximum value of a specified metric in a sibling aggregation and outputs both the value and the key(s) of the bucket(s). The specified metric must be numeric and the sibling aggregation must be a multi-bucket aggregation.

Syntax

A max_bucket aggregation looks like this in isolation:

  1. {
  2.   "max_bucket": {
  3.     "buckets_path": "the_sum"
  4.   }
  5. }

Table 64. max_bucket Parameters

Parameter NameDescriptionRequiredDefault Value

buckets_path

The path to the buckets we wish to find the maximum for (see buckets_path Syntax for more details)

Required

gap_policy

The policy to apply when gaps are found in the data (see Dealing with gaps in the data for more details)

Optional

skip

format

DecimalFormat pattern for the output value. If specified, the formatted value is returned in the aggregation’s value_as_string property

Optional

null

The following snippet calculates the maximum of the total monthly sales:

  1. resp = client.search(
  2.     index="sales",
  3.     size=0,
  4.     aggs={
  5.         "sales_per_month": {
  6.             "date_histogram": {
  7.                 "field": "date",
  8.                 "calendar_interval": "month"
  9.             },
  10.             "aggs": {
  11.                 "sales": {
  12.                     "sum": {
  13.                         "field": "price"
  14.                     }
  15.                 }
  16.             }
  17.         },
  18.         "max_monthly_sales": {
  19.             "max_bucket": {
  20.                 "buckets_path": "sales_per_month>sales"
  21.             }
  22.         }
  23.     },
  24. )
  25. print(resp)
  1. response = client.search(
  2.   index: 'sales',
  3.   body: {
  4.     size: 0,
  5.     aggregations: {
  6.       sales_per_month: {
  7.         date_histogram: {
  8.           field: 'date',
  9.           calendar_interval: 'month'
  10.         },
  11.         aggregations: {
  12.           sales: {
  13.             sum: {
  14.               field: 'price'
  15.             }
  16.           }
  17.         }
  18.       },
  19.       max_monthly_sales: {
  20.         max_bucket: {
  21.           buckets_path: 'sales_per_month>sales'
  22.         }
  23.       }
  24.     }
  25.   }
  26. )
  27. puts response
  1. const response = await client.search({
  2.   index: "sales",
  3.   size: 0,
  4.   aggs: {
  5.     sales_per_month: {
  6.       date_histogram: {
  7.         field: "date",
  8.         calendar_interval: "month",
  9.       },
  10.       aggs: {
  11.         sales: {
  12.           sum: {
  13.             field: "price",
  14.           },
  15.         },
  16.       },
  17.     },
  18.     max_monthly_sales: {
  19.       max_bucket: {
  20.         buckets_path: "sales_per_month>sales",
  21.       },
  22.     },
  23.   },
  24. });
  25. console.log(response);
  1. POST /sales/_search
  2. {
  3.   "size": 0,
  4.   "aggs": {
  5.     "sales_per_month": {
  6.       "date_histogram": {
  7.         "field": "date",
  8.         "calendar_interval": "month"
  9.       },
  10.       "aggs": {
  11.         "sales": {
  12.           "sum": {
  13.             "field": "price"
  14.           }
  15.         }
  16.       }
  17.     },
  18.     "max_monthly_sales": {
  19.       "max_bucket": {
  20.         "buckets_path": "sales_per_month>sales" 
  21.       }
  22.     }
  23.   }
  24. }

buckets_path instructs this max_bucket aggregation that we want the maximum value of the sales aggregation in the sales_per_month date histogram.

And the following may be the response:

  1. {
  2.    "took": 11,
  3.    "timed_out": false,
  4.    "_shards": ...,
  5.    "hits": ...,
  6.    "aggregations": {
  7.       "sales_per_month": {
  8.          "buckets": [
  9.             {
  10.                "key_as_string": "2015/01/01 00:00:00",
  11.                "key": 1420070400000,
  12.                "doc_count": 3,
  13.                "sales": {
  14.                   "value": 550.0
  15.                }
  16.             },
  17.             {
  18.                "key_as_string": "2015/02/01 00:00:00",
  19.                "key": 1422748800000,
  20.                "doc_count": 2,
  21.                "sales": {
  22.                   "value": 60.0
  23.                }
  24.             },
  25.             {
  26.                "key_as_string": "2015/03/01 00:00:00",
  27.                "key": 1425168000000,
  28.                "doc_count": 2,
  29.                "sales": {
  30.                   "value": 375.0
  31.                }
  32.             }
  33.          ]
  34.       },
  35.       "max_monthly_sales": {
  36.           "keys": ["2015/01/01 00:00:00"], 
  37.           "value": 550.0
  38.       }
  39.    }
  40. }

keys is an array of strings since the maximum value may be present in multiple buckets