v.22.6New Feature
Added nonNegativeDerivative Window Function
Added a new window function nonNegativeDerivative(metric_column, timestamp_column[, INTERVAL x SECOND]). #37628 (Andrey Zvonov).Why it matters
This feature addresses the need to calculate the derivative of a metric over time while ensuring the result is never negative, which is useful for analyzing time series data where decreases in values are not meaningful or should be treated as zero, such as counters or cumulative metrics.How to use it
Use thenonNegativeDerivative window function by passing the metric column and the corresponding timestamp column as arguments. Optionally, specify an interval to define the time steps for derivative calculation. For example:SELECT nonNegativeDerivative(metric, timestamp, INTERVAL 1 SECOND) OVER (ORDER BY timestamp) FROM table