Question

A developer instruments a Lambda function with the AWS X-Ray SDK. The function calls DynamoDB and Amazon SNS. In the X-Ray service map, the DynamoDB node shows a red fault indicator, and traces reveal an AccessDeniedException on PutItem calls. The Lambda's own segment shows no code errors before the failed call. What is the MOST likely root cause?

Accepted Answer

The Lambda execution role is missing the dynamodb:PutItem permission for the target table.

Answer

X-Ray sampling rules are dropping the DynamoDB subsegments, causing false faults.

Answer

The DynamoDB table has insufficient provisioned write capacity, causing throttling.

Answer

The Lambda function timeout is too short, interrupting the PutItem call.