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delay

Input Stack:
w: Window
expr: TimeSeriesExpr
 ⇨ Output Stack:
TimeSeriesExpr
 

Delays the values in a time series by shifting them forward by a number of time steps or an amount of time. This creates a lag effect where each value appears later than it originally occurred. Unlike :offset, this operates on the computed time series data rather than changing the time window used for data fetching.

Parameters

  • expr: The time series expression to delay
  • w: How far to delay the values, either a number of time steps, such as 5, or a duration, such as 5m

Delay Size

A number of time steps, 5, shifts the values by 5 intervals, so the amount of time changes with the step size, for example when zooming out to a time frame that causes consolidation. A duration, 5m, shifts by a fixed amount of time independent of the step size. The duration is rounded down to the nearest step boundary, and if the step size is larger than the duration the values are shifted by a single step. The delay must be positive, 0,:delay is rejected.

Examples

Delaying a time series by 5 time steps:

BeforeAfterCombined
name,requestsPerSecond,:eq,
:sum

name,requestsPerSecond,:eq,
:sum,
5,:delay

name,requestsPerSecond,:eq,
:sum,
:dup,
5,:delay

The "Combined" example shows both the original and delayed series overlaid, demonstrating how the delayed series follows the same pattern but shifted later in time.

Delaying by 15 minutes, independent of the step size:

BeforeAfter
name,requestsPerSecond,:eq,
:sum

name,requestsPerSecond,:eq,
:sum,
15m,:delay

Key Differences from :offset

  • :delay: Operates on computed time series values, shifting them within the same time window
  • :offset: Changes the time window used for data fetching, looking at historical data
  • Streaming compatibility: :delay works with streaming queries, :offset does not

Use Cases

  • Change detection: Compare current values with slightly delayed versions to detect trends
  • Alerting: Detect when current metrics deviate from recent patterns
  • Trend analysis: Identify lead/lag relationships between different metrics
  • Smoothing effects: Create visual comparisons between immediate and delayed signals

Since: 1.6

  • :offset - Shift the time window for data fetching (complementary approach)
  • :dup - Duplicate series for comparison (commonly used with delay)
  • :sub - Calculate differences between original and delayed series
  • :time - Generate time-based values for reference