Posted On: Feb 9, 2023

AWS Lambda has launched three new metrics AsyncEventsReceived, AsyncEventAge and AsyncEventsDropped, to monitor the performance of asynchronous event processing. Until now, Lambda customers had little visibility into the processing of asynchronous requests and had to rely on Lambda service teams to resolve any processing delays leading to inefficiencies in asynchronous event processing. With these new metrics customers have better visibility into their asynchronous invocations and can track the events sent to Lambda, monitor delays in event processing and take corrective actions if required.

AsyncEventsReceived is a measure of the total number of events Lambda was able to successfully queue for processing. This metric provides transparency into the number of events sent to the Lambda function for asynchronous invocation. Developers can monitor this metric and alarm on undesirable number of events sent by an event source to diagnose trigger misconfigurations or runaway functions.

AsyncEventAge is a measure of time between Lambda successfully queuing the event and invoking the function. This metric increases, if events are getting retried due to execution failures or throttles. This metric provides transparency into the event processing time of your asynchronous Lambda invocations. Developers can monitor this metric and alarm on different statistics for processing delays.

AsyncEventsDropped is a measure of the total number of events that were dropped without successfully executing the function. If an OnFailure destination or Dead-Letter-Queue (DLQ) is configured, events are sent to it before being dropped. Events could be dropped for multiple reasons such as Maximum Event Age exceeded, Maximum Retry Attempts exhausted or function with reserved concurrency set to 0.

To learn more about these metrics visit Lambda Developer Guide and AWS Compute Blog. Lambda sends metrics to Amazon CloudWatch at no cost to you. However, charges apply for CloudWatch Metric Streams and CloudWatch Alarms. See CloudWatch pricing for information.