DynamoDB ConsumedReadCapacity different in CloudWatch and CostExplorer

Question

CloudWatch Metrics for DynamoDB only show a ConsumedReadCapacity of a few thousand units for a particular month. However, in CostExplorer I see I get billed for several million units in the same month (which is the more plausible number). Where does that difference come from? How can i get the true consumption in CloudWatch (with its finer granularity)?

Chenjie Ni
2 months ago
You are probably looking at the ConsumedReadCapacity for one of your tables in CloudWatch

Answer

Hi,

By default cloudWatch metrics for dynamoDB shows ConsumedReadCapacityUnits for a particular table. You can refer [this](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/metrics-dimensions.html#ConsumedReadCapacityUnits) link.

* Units: Count
* Dimensions: TableName, GlobalSecondaryIndexName

In CostExplorer by default, Cost Explorer does not provide a summary of the costs for any one specific table, as it will combine the costs of multiple tables into a total. However, you can use AWS resource tagging to identify each table by a metadata tag. Tags are key-value pairs you can use for a variety of purposes, such as to identify all resources belonging to a project or department. See [this](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/CostOptimization_TableLevelCostAnalysis.html#CostOptimization_TableLevelCostAnalysis_Tagging) link.

Having said above, it might be possible that in cloudwatch, per table metrics is showing and in cost explorer, consumed read capacity units of all tables combined. Please make sure that similar dimensions and statistics are getting used in both cloudwatch and cost explorer.

DynamoDB ConsumedReadCapacity different in CloudWatch and CostExplorer

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