presto-main/src/main/java/io/prestosql/operator/scalar/JsonFunctions.java/JsonFunctions/jsonSize
class JsonFunctions:    @ScalarFunction
    @SqlNullable
    @SqlType(StandardTypes.BIGINT)
    public static Long jsonSize(@SqlType(StandardTypes.JSON) Slice json, @SqlType(JsonPathType.NAME) JsonPath jsonPath)
    {
        return JsonExtract.extract(json, jsonPath.getSizeExtractor());
    }