As of November 2, 2023, we've added a new threshold type to Canary called relative percentile. A relative percentile threshold detects when your observed metric deviates from the historical disbursement of the middle range of your data. Canary calculates this middle range by looking at your historical data from the chosen Lookback Window and identifying the 15th percentile (a value higher than 15% of your data disbursement) and the 85th percentile (a value higher than 85% of your data disbursement). Any time your data drops above or below that middle range—depending on the Direction chosen—Canary will alert you.
For example, consider a situation in which you created a trigger with the following settings:
- Metric: Transaction Count
- Threshold Type: Relative Percentile
- Direction: Below or At
- Lookback Window: 7 (days)
- Aggregation Period: Day
- Evaluation Time: 12:00 PM
This trigger would then monitor your total transaction count every day at 12:00 PM and alert you when the number of transactions processed drops below the 15th percentile of your transaction count measurements from the last seven days. Canary runs the trigger today and sees the following transaction counts from the last week:
Canary then calculates the 15th percentile to be ~59 and the 85th percentile to be ~126. The historical middle range of your transaction count metric would be any value between 59 and 126. Since your trigger has the Direction set to Below or At, you would then receive an alert if your transaction count today dropped below 59. Tomorrow, Canary will run this trigger again at 12:00 PM, looking at data from the last 7 days and calculating a new middle range with that new data set.