Auto-interval Date Histogram Aggregationedit

A multi-bucket aggregation similar to the Date Histogram Aggregation except instead of providing an interval to use as the width of each bucket, a target number of buckets is provided indicating the number of buckets needed and the interval of the buckets is automatically chosen to best achieve that target. The number of buckets returned will always be less than or equal to this target number.

The buckets field is optional, and will default to 10 buckets if not specified.

Requesting a target of 10 buckets.

POST /sales/_search?size=0
{
    "aggs" : {
        "sales_over_time" : {
            "auto_date_histogram" : {
                "field" : "date",
                "buckets" : 10
            }
        }
    }
}

Keysedit

Internally, a date is represented as a 64 bit number representing a timestamp in milliseconds-since-the-epoch. These timestamps are returned as the bucket keys. The key_as_string is the same timestamp converted to a formatted date string using the format specified with the format parameter:

Tip

If no format is specified, then it will use the first date format specified in the field mapping.

POST /sales/_search?size=0
{
    "aggs" : {
        "sales_over_time" : {
            "auto_date_histogram" : {
                "field" : "date",
                "buckets" : 5,
                "format" : "yyyy-MM-dd" 
            }
        }
    }
}

Supports expressive date format pattern

Response:

{
    ...
    "aggregations": {
        "sales_over_time": {
            "buckets": [
                {
                    "key_as_string": "2015-01-01",
                    "key": 1420070400000,
                    "doc_count": 3
                },
                {
                    "key_as_string": "2015-02-01",
                    "key": 1422748800000,
                    "doc_count": 2
                },
                {
                    "key_as_string": "2015-03-01",
                    "key": 1425168000000,
                    "doc_count": 2
                }
            ],
            "interval": "1M"
        }
    }
}