TTL Expire Event on Amazon Keyspaces

Unfortunately, Amazon Keyspaces does not provide a specific TTL expired event that you can directly subscribe to or receive notifications for. The Time to Live (TTL) feature in Amazon Keyspaces is designed to automatically expire and delete data without requiring additional management or intervention.

However, Amazon Keyspaces does offer a way to monitor TTL-related activity through Amazon CloudWatch metrics. Specifically, there is a metric called "TTLDeletes" available in CloudWatch. This metric represents the units consumed to delete or update data in a row using the Time to Live feature.

While this metric doesn't provide a direct event for each TTL expiration, it does allow you to monitor the overall TTL deletion activity in your Keyspaces tables. You can use this metric to set up CloudWatch alarms or create dashboards to keep track of TTL-related operations.

It's important to note that the TTL feature in Amazon Keyspaces is fully managed. This means that expired data is automatically filtered out from query results and deleted from storage within about 10 days of expiration, though this process may sometimes take longer. The service handles this process transparently without requiring you to manage additional read/write capacity or low-level operations like compaction.

If you need more granular monitoring or event-based notifications for TTL expirations, you may need to implement a custom solution within your application logic to track and respond to data expiration based on your specific requirements.
Sources
Expire data with Time to Live (TTL) for Amazon Keyspaces (for Apache Cassandra) - Amazon Keyspaces (for Apache Cassandra)
Amazon Keyspaces for Apache Cassandra features - Amazon Web Services