Average bucket aggregations
The avg_bucket aggregation is a sibling aggregation that calculates the average of a metric in each bucket of a previous aggregation.
The specified metric must be numeric, and the sibling aggregation must be a multi-bucket aggregation.
Parameters
The avg_bucket aggregation takes the following parameters.
| Parameter | Required/Optional | Data type | Description |
|---|---|---|---|
buckets_path | Required | String | The path of the aggregation buckets to be aggregated. See Buckets path. |
gap_policy | Optional | String | The policy to apply to missing data. Valid values are skip and insert_zeros. Default is skip. See Data gaps. |
format | Optional | String | A DecimalFormat formatting string. Returns the formatted output in the aggregation’s value_as_string property. |
Example
The following example creates a date histogram with a one-month interval from the OpenSearch Dashboards e-commerce sample data. The sum subaggregation calculates the sum of bytes for each month. Finally, the avg_bucket aggregation calculates the average number of bytes per month from these sums:
POST opensearch_dashboards_sample_data_logs/_search
{
"size": 0,
"aggs": {
"visits_per_month": {
"date_histogram": {
"field": "@timestamp",
"interval": "month"
},
"aggs": {
"sum_of_bytes": {
"sum": {
"field": "bytes"
}
}
}
},
"avg_monthly_bytes": {
"avg_bucket": {
"buckets_path": "visits_per_month>sum_of_bytes"
}
}
}
}
Example response
The aggregation returns the average bytes from the monthly buckets:
{
"took": 43,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 10000,
"relation": "gte"
},
"max_score": null,
"hits": []
},
"aggregations": {
"visits_per_month": {
"buckets": [
{
"key_as_string": "2025-03-01T00:00:00.000Z",
"key": 1740787200000,
"doc_count": 480,
"sum_of_bytes": {
"value": 2804103
}
},
{
"key_as_string": "2025-04-01T00:00:00.000Z",
"key": 1743465600000,
"doc_count": 6849,
"sum_of_bytes": {
"value": 39103067
}
},
{
"key_as_string": "2025-05-01T00:00:00.000Z",
"key": 1746057600000,
"doc_count": 6745,
"sum_of_bytes": {
"value": 37818519
}
}
]
},
"avg_monthly_bytes": {
"value": 26575229.666666668
}
}
}