% This is generated by ESQL's AbstractFunctionTestCase. Do not edit it. See ../README.md for how to regenerate it.

**Description**

Calculates the per-second average rate of increase of a [counter](docs-content://manage-data/data-store/data-streams/time-series-data-stream-tsds.md#time-series-metric). Rate calculations account for breaks in monotonicity, such as counter resets when a service restarts, and extrapolate values within each bucketed time interval. Rate is the most appropriate aggregate function for counters. It is only allowed in a [STATS](/reference/query-languages/esql/commands/stats-by.md) command under a [`TS`](/reference/query-languages/esql/commands/ts.md) source command, to be properly applied per time series.