Keyspaces max WCU for partition when deleting data with queries

Hello,

Firstly, Amazon Keyspaces charges you for the reads and writes that you perform on your tables in terms of read request units (RRUs) and write request units (WRUs). [1]

Secondly, one WRU represents one write for a row up to 1 KB in size. If you need to write a row that is larger than 1 KB, the write operation uses additional WRUs. The total number of WRUs required depends on the row size. For example, if your row size is 2 KB, you require 2 WRUs to perform one write request. Also, one WCU represents one write per second for a row up to 1 KB in size. If you need to write a row that is larger than 1 KB, the write operation uses additional WCUs.

The gist here is that the delete operations are considered write operations so they will consume WriteRequestUnits (WRUs) for On-Demand tables and WriteCapacityUnits (WCUs) for Provisioned tables. Hence, a record of 100 KB will require 100 WCU to sustain 1 write request per second.

In regards to partition (which have a throughput limit of 3,000 RCUs or 1,000 WCUs), if all the 100 KB records were stored on a single partition, you could delete 10 records per second, consuming 1000 WCU per second and not exceed the partition limit.

Additionally, please refer to the following documentation [2][3] for understanding rate limit approaches.

Please let us know if this resolves your issue. If you need assistance with further troubleshooting, please open a support case and we'll be glad to assist!

References:

[1] https://docs.aws.amazon.com/keyspaces/latest/devguide/ReadWriteCapacityMode.html

[2] https://docs.aws.amazon.com/keyspaces/latest/devguide/autoscaling.html

[3] https://docs.aws.amazon.com/keyspaces/latest/devguide/data-modeling.html