Introduction

This action lowers the provisioned read (RCU) and write (WCU) capacity on a DynamoDB table — and on every Global Secondary Index attached to it — to force ProvisionedThroughputExceededException for callers. Original capacities are captured during Prepare and restored on Stop.

Tables in PAY_PER_REQUEST (on-demand) mode are rejected at Prepare because they have no provisioned capacity to lower.

Use Cases

• Verify how the application behaves when DynamoDB returns ProvisionedThroughputExceededException.
• Test the SDK's built-in retry/backoff behaviour under sustained throttling.
• Stress monitoring/alerting on the ThrottledRequests and UserErrors CloudWatch metrics.

Rollback

On Stop, the table is updated back to the original ReadCapacityUnits and WriteCapacityUnits captured during Prepare. Each GSI's per-index capacity is restored individually.

Observed AWS-side behaviour for capacity parameters

• Daily decrease quota — AWS limits each PROVISIONED table to a small number of capacity decreases per UTC day (4 per day at the base rate; the cap grows if the table was previously increased during the same UTC day). On exhaustion, UpdateTable fails with LimitExceededException: Subscriber limit exceeded: Provisioned throughput decreases are limited within a given UTC day. Re-running the attack many times against the same table within a single day will start failing.
• Auto Scaling reaction window — if Application Auto Scaling is attached to the table or its GSIs, the autoscaler will scale capacity back up within minutes regardless of Stop. The attack still exercises the throttle path during the autoscaler's reaction window, but sustained throttling beyond a few minutes will not happen with autoscaling enabled.
• Propagation delay — DynamoDB processes capacity changes asynchronously. The table briefly enters the UPDATING state; throttling kicks in once the change is applied (usually within seconds). Reads/writes already in-flight at Start are not retroactively throttled.

Parameters

Parameter	Description	Default
Duration	How long the lowered capacity stays in effect. Restored on stop.	60s
Target read capacity (RCU)	New ReadCapacityUnits for the table and each GSI.	1
Target write capacity (WCU)	New WriteCapacityUnits for the table and each GSI.	1