Why are my metrics on DynamoDB different from the CloudWatch metrics?

Short description

The metrics on the CloudWatch console are based on raw data, but many metrics on the DynamoDB console are based on processed data. For example, the ConsumedReadCapacityUnits metric on CloudWatch calculates the Consumed metric from the Read usage (average units/second) graph on DynamoDB.

When you choose different settings for a metric on the CloudWatch console, metrics can look different between CloudWatch and DynamoDB. For example, your CloudWatch metrics might have different Statistic, Period, and Duration settings. For more information on these settings, see DynamoDB metrics and dimensions.

Resolution

To make sure that the graphs on both CloudWatch and DynamoDB match, set the metric settings to be the same. For example, to change a graph on CloudWatch to look like the Read usage (average units/second) graph on DynamoDB, complete the following steps:

1. Open the DynamoDB console.
2. In the navigation pane, select the Tables tab. Then, choose your table.
3. Select the Monitor tab.
4. To open the CloudWatch console from DynamoDB, choose View all CloudWatch metrics.
5. Choose the category that the metric is in. For this example, select Table metrics.
6. Check the box next to the table name for the ConsumedReadCapacityUnits metric.
7. Choose the Graphed metrics tab.
8. In the Statistic dropdown list, choose Sum.
9. In the Period dropdown list, choose 1 Minute.
10. If the CloudWatch graph uses provisioned values, first use the arrows in the Y Axis column to move the values to the right Y axis. Then, move the consumed values to the left Y axis.
11. Use a math expression to divide the average units by 60 seconds (for example, m2/60).

Missing metrics

If CloudWatch doesn't list a metric from DynamoDB, then DynamoDB doesn't have recent data for that metric. CloudWatch lists only the metrics that are active during the past two weeks. For more information, see ListMetrics.

Related information

Using math expressions with CloudWatch metrics

Monitoring metrics in DynamoDB with Amazon CloudWatch

Graph a metric