# bottomk Metrics 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))`