Schema for Statistics (statistics.json file)

The schema defined in the statistics.json file specifies the statistical parameters to be calculated for the baseline and data that is captured. It also configures the bucket to be used by KLL, a very compact quantiles sketch with lazy compaction scheme.

{
    "version": 0,
    # dataset level stats
    "dataset": {
        "item_count": number
    },
    # feature level stats
    "features": [
        {
            "name": "feature-name",
            "inferred_type": "Fractional" | "Integral",
            "numerical_statistics": {
                "common": {
                    "num_present": number,
                    "num_missing": number
                },
                "mean": number,
                "sum": number,
                "std_dev": number,
                "min": number,
                "max": number,
                "distribution": {
                    "kll": {
                        "buckets": [
                            {
                                "lower_bound": number,
                                "upper_bound": number,
                                "count": number
                            }
                        ],
                        "sketch": {
                            "parameters": {
                                "c": number,
                                "k": number
                            },
                            "data": [
                                [
                                    num,
                                    num,
                                    num,
                                    num
                                ],
                                [
                                    num,
                                    num
                                ][
                                    num,
                                    num
                                ]
                            ]
                        }#sketch
                    }#KLL
                }#distribution
            }#num_stats
        },
        {
            "name": "feature-name",
            "inferred_type": "String",
            "string_statistics": {
                "common": {
                    "num_present": number,
                    "num_missing": number
                },
                "distinct_count": number,
                "distribution": {
                    "categorical": {
                         "buckets": [
                                {
                                    "value": "string",
                                    "count": number
                                }
                          ]
                     }
                }
            },
            #provision for custom stats
        }
    ]
}