bottomk Operator
The bottomk operator applies a specified aggregation function to the time series that match the query selector, and returns the n time series that have the lowest evaluated value over the query time range.
Syntax
bottomk (N, SCALAR_EXPRESSION) [by FIELD [, FIELD, ...]]
Where:
N is the number of time series to chart
SCALAR_EXPRESSION is one these functions:
| Function | Description |
|---|---|
| min | Rank matching time series by which had the minimum value of the metric across the time range, and return the bottom n time series. |
| max | Rank matching time series by which had the maximum value of the metric across the time range, and return the bottom n time series. |
| avg | Rank matching time series by the average value of the metric across the time range, and return the bottom n time series. |
| count | Rank matching time series by the count of the metric values across the time range, and return the bottom n time series. |
| sum | Rank matching time series by the sum of the metric values across the time range, and return the bottom n time series. |
| pct(n) | Return the n time series for which the calculated percentile of the metric values across the time range was lowest, and return the bottom n. |
| latest | Rank matching time series by when the most recent data point was received, and return the bottom n time series. |
Examples
Bottom time series by avg value
This query ranks the time series that match the query selector by the average value of the CPU_Sys metric over the time range, and returns the bottom 5 time series.
_contentType=HostMetrics metric=CPU_Sys | bottomk (5, avg)
The 5 time series with the lowest 99% confidence interval
This query applies a math expression to each time series that match the query selector. The math expression calculates the average value over the time range, plus 3 standard deviations. The time series are ranked by the calculated value, and the bottom 5 time series are returned.
_contentType=HostMetrics metric=CPU_Sys | bottomk (5, avg + 3 * stddev)
Bottom time series by specified percentile
This query calculates 10th percentile of the Mem_FreePercent metric for each time series that match the query, ranks the time series on that basis, and returns the bottom 5 time series.
_contentType=HostMetrics metric=Mem_FreePercent | bottomk (5, pct (10))
