关于lambda持续时间的Cloudwatch警报未触发

Question

即使lambda延迟超过阈值，也不会触发关于lambda的Cloudwatch警报。在上周，lambda延迟几次达到15分钟。以下是警报的详细信息。

Alarm view

EventTransformerLambdaLatencyAlarm:
    Properties:
      AlarmDescription: "Alarm if EventTransformer lambda takes more than the threshold to complete"
      AlarmName: "EventTransformerTaskLatencyAlarm"
      ComparisonOperator: "GreaterThanOrEqualToThreshold"
      Dimensions:
        - Name: "FunctionName"
          Value: {Ref: EventTransformerTaskName}
      EvaluationPeriods: 1
      MetricName: "Duration"
      Namespace: "AWS/Lambda"
      Period: !!int "300"
      Statistic: "Maximum"
      Threshold: !!int "780000" # 13 minutes in millis
      TreatMissingData: "notBreaching"
    Type: "AWS::CloudWatch::Alarm"

当我在警报控制台中单击“查看度量标准”时，它会在红线上方显示数据点。

Metrics breached last week

任何建议都会有所帮助