CloudWatch throttling metrics

This page provides a comprehensive guide to CloudWatch metrics specifically designed to help you identify, diagnose, and resolve throttling issues in your DynamoDB tables and indexes.

General throttling metrics

• ThrottledRequests

  • Incremented by one when any event within a request is throttled, regardless of how many individual events within that request are throttled. For example, when updating an item in a table with Global Secondary Indexes (GSIs), multiple events occur: a write operation to the base table and a write operation to each index. If any of these individual events are throttled, the ThrottledRequests metric is only incremented once.

    This behavior is important to understand when monitoring and troubleshooting DynamoDB performance, as it may mask the true extent of throttling. For more comprehensive insights, compare the ThrottledRequests metric with the specific event-level metrics like ReadThrottleEvents, WriteThrottleEvents, and targeted metrics such as ReadKeyRangeThroughputThrottleEvents for example. The complete list of these cause-specific metrics is available in this page. Each metric corresponds to particular throttling reasons that are captured within the throttling exception. For guidance on retrieving and interpreting these reasons during throttling events, see the Diagnosing throttling section which provides instructions for identifying and resolving the root causes of throttling issues.

• ReadThrottleEvents

  • Watch for requests that exceed the provisioned RCU for a table or GSI.

• WriteThrottleEvents

  • Watch for requests that exceed the provisioned WCU for a table or GSI.

Detailed throttling metrics by cause

On-Demand throughput throttling

• ReadMaxOnDemandThroughputThrottleEvents

  • Number of read requests throttled due to on-demand maximum throughput.

• WriteMaxOnDemandThroughputThrottleEvents

  • Number of write requests throttled due to on-demand maximum throughput.

Account-Level throttling

• ReadAccountLimitThrottleEvents

  • Number of read requests throttled due to account limits.

• WriteAccountLimitThrottleEvents

  • Number of write requests throttled due to account limits.

Partition-Level throttling

• ReadKeyRangeThroughputThrottleEvents

  • Number of read requests throttled due to partition limits.

• WriteKeyRangeThroughputThrottleEvents

  • Number of write requests throttled due to partition limits.

Capacity analysis metrics

• OnlineIndexConsumedWriteCapacity

  • When you add a new GSI to an existing table, DynamoDB performs a backfill operation that copies data from the base table to the new index. This process consumes write capacity units. The OnlineIndexConsumedWriteCapacity metric tracks this specific consumption.

    This consumption is separate from and additional to the regular write operations tracked by ConsumedWriteCapacityUnits. The regular ConsumedWriteCapacityUnits metric for a GSI does not include the write capacity consumed during the initial index creation process.

• ProvisionedReadCapacityUnits and ProvisionedWriteCapacityUnits

  • View how many provisioned read or write capacity units were consumed over the specified time period, for a table or a specified global secondary index.

  • Note that the TableName dimension returns ProvisionedReadCapacityUnits for the table only by default. To view the number of provisioned read or write capacity units for a global secondary index, you must specify both TableName and GlobalSecondaryIndexName.

• ConsumedReadCapacityUnits and ConsumedWriteCapacityUnits

  • View how many read or write capacity units were consumed over the specified time period. ConsumedWriteCapacityUnits does not include the write capacity consumed during the initial index creation process.

For more information on DynamoDB CloudWatch metrics, see DynamoDB Metrics and dimensions.