Types of metrics for Lambda functions

Invocations – The number of times that your function code is invoked, including successful invocations and invocations that result in a function error. Invocations aren't recorded if the invocation request is throttled or otherwise results in an invocation error. The value of Invocations equals the number of requests billed.

Errors – The number of invocations that result in a function error. Function errors include exceptions that your code throws and exceptions that the Lambda runtime throws. The runtime returns errors for issues such as timeouts and configuration errors. To calculate the error rate, divide the value of Errors by the value of Invocations. Note that the timestamp on an error metric reflects when the function was invoked, not when the error occurred.

DeadLetterErrors – For asynchronous invocation, the number of times that Lambda attempts to send an event to a dead-letter queue (DLQ) but fails. Dead-letter errors can occur due to incorrectly set resources or size limits.

DestinationDeliveryFailures – For asynchronous invocation and supported event source mappings, the number of times that Lambda attempts to send an event to a destination but fails. For event source mappings, Lambda supports destinations for stream sources (DynamoDB and Kinesis). Delivery errors can occur due to permissions errors, incorrectly configured resources, or size limits. Errors can also occur if the destination you have configured is an unsupported type such as an Amazon SQS FIFO queue or an Amazon SNS FIFO topic.

Throttles – The number of invocation requests that are throttled. When all function instances are processing requests and no concurrency is available to scale up, Lambda rejects additional requests with a TooManyRequestsException error. Throttled requests and other invocation errors don't count as either Invocations or Errors.

OversizedRecordCount – For Amazon DocumentDB event sources, the number of events your function receives from your change stream that are over 6 MB in size. Lambda drops the message and emits this metric.

ProvisionedConcurrencyInvocations – The number of times that your function code is invoked using provisioned concurrency.

ProvisionedConcurrencySpilloverInvocations – The number of times that your function code is invoked using standard concurrency when all provisioned concurrency is in use.

RecursiveInvocationsDropped – The number of times that Lambda has stopped invocation of your function because it has detected that your function is part of an infinite recursive loop. Recursive loop detection monitors how many times a function is invoked as part of a chain of requests by tracking metadata added by supported AWS SDKs. By default, if your function is invoked as part of a chain of requests approximately 16 times, Lambda drops the next invocation. If you disable recursive loop detection, this metric is not emitted. For more information about this feature, see Use Lambda recursive loop detection to prevent infinite loops.

SignatureValidationErrors – The number of times a code package deployment has occurred with signature validation failures when the code signing configuration policy is set to Warn. This metric is emitted when the expiry, mismatch, or revocation checks fail but the deployment is still allowed due to the Warn policy setting. For more information about code signing, see Using code signing to verify code integrity with Lambda.

Duration – The amount of time that your function code spends processing an event. The billed duration for an invocation is the value of Duration rounded up to the nearest millisecond. Duration does not include cold start time.

PostRuntimeExtensionsDuration – The cumulative amount of time that the runtime spends running code for extensions after the function code has completed.

IteratorAge – For DynamoDB, Kinesis, and Amazon DocumentDB event sources, the age of the last record in the event in milliseconds. This metric measures the time between when a stream receives the record and when the event source mapping sends the event to the function.

OffsetLag – For self-managed Apache Kafka and Amazon Managed Streaming for Apache Kafka (Amazon MSK) event sources, the difference in offset between the last record written to a topic and the last record that your function's consumer group processed. Though a Kafka topic can have multiple partitions, this metric measures the offset lag at the topic level.

ConcurrentExecutions – The number of function instances that are processing events. If this number reaches your concurrent executions quota for the Region, or the reserved concurrency limit on the function, then Lambda throttles additional invocation requests.

ProvisionedConcurrentExecutions – The number of function instances that are processing events using provisioned concurrency. For each invocation of an alias or version with provisioned concurrency, Lambda emits the current count. If your function is inactive or not receiving requests, Lambda doesn't emit this metric.

ProvisionedConcurrencyUtilization – For a version or alias, the value of ProvisionedConcurrentExecutions divided by the total amount of provisioned concurrency configured. For example, if you configure a provisioned concurrency of 10 for your function, and your ProvisionedConcurrentExecutions is 7, then your ProvisionedConcurrencyUtilization is 0.7.

If your function is inactive or not receiving requests, Lambda doesn't emit this metric because it is based on ProvisionedConcurrentExecutions. Keep this in mind if you use ProvisionedConcurrencyUtilization as the basis for CloudWatch alarms.

UnreservedConcurrentExecutions – For a Region, the number of events that functions without reserved concurrency are processing.

ClaimedAccountConcurrency – For a Region, the amount of concurrency that is unavailable for on-demand invocations. ClaimedAccountConcurrency is equal to UnreservedConcurrentExecutions plus the amount of allocated concurrency (i.e. the total reserved concurrency plus total provisioned concurrency). For more information, see Working with the ClaimedAccountConcurrency metric.

AsyncEventsReceived – The number of events that Lambda successfully queues for processing. This metric provides insight into the number of events that a Lambda function receives. Monitor this metric and set alarms for thresholds to check for issues. For example, to detect an undesirable number of events sent to Lambda, and to quickly diagnose issues resulting from incorrect trigger or function configurations. Mismatches between AsyncEventsReceived and Invocations can indicate a disparity in processing, events being dropped, or a potential queue backlog.

AsyncEventAge – The time between when Lambda successfully queues the event and when the function is invoked. The value of this metric increases when events are being retried due to invocation failures or throttling. Monitor this metric and set alarms for thresholds on different statistics for when a queue buildup occurs. To troubleshoot an increase in this metric, look at the Errors metric to identify function errors and the Throttles metric to identify concurrency issues.

AsyncEventsDropped – The number of events that are dropped without successfully executing the function. If you configure a dead-letter queue (DLQ) or OnFailure destination, then events are sent there before they're dropped. Events are dropped for various reasons. For example, events can exceed the maximum event age or exhaust the maximum retry attempts, or reserved concurrency might be set to 0. To troubleshoot why events are dropped, look at the Errors metric to identify function errors and the Throttles metric to identify concurrency issues.