Skip to content
ClickHouse Docs
ClickHouse DocsClickHouse Docs

timeSeriesRateToGrid

timeSeriesRateToGrid

引入版本:v25.6.0

该聚合函数接收由时间戳和值组成的时间序列数据,并在由起始时间戳、结束时间戳和 step 定义的规则时间网格上,根据这些数据计算 类 PromQL rate。对于网格上的每个点,计算 rate 时会使用指定时间窗口内的样本。

如果多个样本具有相同的时间戳,则仅使用其中一个:值最大的样本。NaN 值会输给任何其他值,因此仅当该时间戳处的所有样本均为 NaN 时,才会使用 NaN 值。

语法

timeSeriesRateToGrid(start_timestamp, end_timestamp, grid_step, staleness)(timestamp, value)

参数

  • start_timestamp — 指定网格的起始时间。使用 DateTime64 时间戳实参时,也可以是小数、包含数字的字符串或日期时间文本。UInt32DateTimeDateTime64Float*Decimal*String
  • end_timestamp — 指定网格的结束时间。使用 DateTime64 时间戳实参时,也可以是小数、包含数字的字符串或日期时间文本。UInt32DateTimeDateTime64Float*Decimal*String
  • grid_step — 指定网格步长,单位为秒。使用 DateTime64 时间戳实参时,也可以是小数、包含数字的字符串,或类似 '15s' 或 '1m' 的时长。UInt32Float*Decimal*String
  • staleness — 指定参与计算的样本允许的最大陈旧时间,单位为秒。陈旧时间窗口为左开右闭区间。使用 DateTime64 时间戳实参时,也可以是小数、包含数字的字符串,或类似 '15s' 或 '1m' 的时长。UInt32Float*Decimal*String

实参

返回值

返回指定网格上的速率值。返回的数组中,每个时间网格点对应一个值。如果在窗口内没有足够的样本来计算某个网格点的速率值,则该值为 NULL。Array(Nullable(Float64))

示例

使用单个时间戳-值对的基本用法

SET allow_experimental_time_series_aggregate_functions = 1;
WITH
    -- NOTE: the gap between 140 and 190 is to show how values are filled for ts = 150, 165, 180 according to window parameter
    [110, 120, 130, 140, 190, 200, 210, 220, 230]::Array(DateTime) AS timestamps,
    [1, 1, 3, 4, 5, 5, 8, 12, 13]::Array(Float32) AS values, -- array of values corresponding to timestamps above
    90 AS start_ts,       -- start of timestamp grid
    90 + 120 AS end_ts,   -- end of timestamp grid
    15 AS step_seconds,   -- step of timestamp grid
    45 AS window_seconds  -- "staleness" window
SELECT timeSeriesRateToGrid(start_ts, end_ts, step_seconds, window_seconds)(timestamp, value)
FROM
(
    -- This subquery converts arrays of timestamps and values into rows of `timestamp`, `value`
    SELECT
        arrayJoin(arrayZip(timestamps, values)) AS ts_and_val,
        ts_and_val.1 AS timestamp,
        ts_and_val.2 AS value
);
┌─timeSeriesRateToGrid(start_ts, end_ts, step_seconds, window_seconds)(timestamp, value)─┐
│ [NULL,NULL,0,0.06666667,0.1,0.055555556,NULL,NULL,0.083333336]                         │
└────────────────────────────────────────────────────────────────────────────────────────┘

使用数组类型实参

SET allow_experimental_time_series_aggregate_functions = 1;
WITH
    [110, 120, 130, 140, 190, 200, 210, 220, 230]::Array(DateTime) AS timestamps,
    [1, 1, 3, 4, 5, 5, 8, 12, 13]::Array(Float32) AS values,
    90 AS start_ts,
    90 + 120 AS end_ts,
    15 AS step_seconds,
    45 AS window_seconds
SELECT timeSeriesRateToGrid(start_ts, end_ts, step_seconds, window_seconds)(timestamps, values);
┌─timeSeriesRateToGrid(start_ts, end_ts, step_seconds, window_seconds)(timestamps, values)─┐
│ [NULL,NULL,0,0.06666667,0.1,0.055555556,NULL,NULL,0.083333336]                           │
└──────────────────────────────────────────────────────────────────────────────────────────┘
Navigation