AWS Lambda adds support for percentiles on Amazon CloudWatch Metrics
You can now visualize and alarm on a custom percentile of the AWS Lambda metric for invocation duration.
A percentile is a statistic which tells you the relative standing of a value in a dataset. Percentiles are useful when applied to metrics that exhibit large variances. They can help you understand the distribution of a metric, spot outliers, and find hard-to-spot situations that create a poor customer experience for a subset of your users.
The AWS Lambda metric for duration already supports statistics such as average, minimum or maximum. Now, percentiles for the duration metric provide you with more granular insight into your function executions and help you observe and diagnose anomalies in your Lambda applications. For example, the 99th percentile of the duration metric will tell you that 1% of the time, your function’s execution duration is above a certain amount.
To get started, navigate to the Duration metric for your Lambda functions in the Amazon CloudWatch console and select a percentile from the drop-down list. You can also enter a percentile of your choice, in 0.1% increments.
Percentile support for the duration metric is available in all regions where AWS Lambda is available. For more information, see the AWS region table. To learn more about CloudWatch Metrics for AWS Lambda functions, visit the AWS Lambda Developer Guide.