Trend is an object for representing a custom metric that allows for calculating different statistics on the added values (min, max, average or percentiles). It is one of the four custom metrics.
|name||string||The name of the custom metric.|
|isTime||boolean||A boolean indicating whether the values added to the metric are time values or just untyped values.|
|Trend.add(value, [tags])||Add a value to the trend metric.|
When Trend is used in a threshold expression, there are a range of variables that can be used.
- avg for average
- min for minimum
- max for maximum
- med for median
- p(N) for specific percentile. N is a number between 0.0 and 100.0 meaning the percentile value to look at, e.g. p(99.99) means the 99.99th percentile.
The unit of these variables and functions are all in milliseconds.
- p(95) < 400 // 95% of requests must finish below 400ms
- p(99) < 1000 // 99% of requests must finish within 1s.
- p(50) < 200 // half of requests must finish within 200ms.
- max < 3000 // the slowest request must finish within 3s.
⚠️ Don't use min and max in thresholds
We don't recommend using min and max for specifying thresholds because these values represent outliers. Use percentiles instead.