rolling_percentile() plugin

Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer

Returns an estimate for the specified percentile of the ValueColumn population in a rolling (sliding) BinsPerWindow size window per BinSize.

The plugin is invoked with the evaluate operator.

Syntax

T | evaluate rolling_percentile(ValueColumn, Percentile, IndexColumn, BinSize, BinsPerWindow [, dim1, dim2, ...] )

Learn more about syntax conventions.

Parameters

Returns

Returns a table with a row per each bin (and combination of dimensions if specified) that has the rolling percentile of values in the window ending at the bin (inclusive). Output table schema is:

Examples

Rolling 3-day median value per day

The next query calculates a 3-day median value in daily granularity. Each row in the output represents the median value for the last 3 bins (days), including the bin itself.

let T = 
    range idx from 0 to 24 * 10 - 1 step 1
    | project Timestamp = datetime(2018-01-01) + 1h * idx, val=idx + 1
    | extend EvenOrOdd = iff(val % 2 == 0, "Even", "Odd");
T  
| evaluate rolling_percentile(val, 50, Timestamp, 1d, 3)

Output

Rolling 3-day median value per day by dimension

Same example from above, but now also calculates the rolling window partitioned for each value of the dimension.

let T = 
    range idx from 0 to 24 * 10 - 1 step 1
    | project Timestamp = datetime(2018-01-01) + 1h * idx, val=idx + 1
    | extend EvenOrOdd = iff(val % 2 == 0, "Even", "Odd");
T  
| evaluate rolling_percentile(val, 50, Timestamp, 1d, 3, EvenOrOdd)

Output