After you enable CTS, whenever an SMN API is called, the operation is recorded in a log file, which is then delivered to a specified OBS bucket for storage.

However, if someone makes an API call to cancel a subscription without login, CTS will not record the operation. For example, if a subscriber clicks the link in an email notification to cancel the subscription, the Unsubscribe API is called, but CTS does not record the operation.

Table 1 lists the SMN operations that will be recorded by CTS.

**Table 1** SMN operations recorded by CTS
Operation	Resource	Trace Name
Creating a topic	Topic	createTopic
Deleting a topic	Topic	deleteTopic
Updating a topic	Topic	updateTopic
Updating attributes of a topic	Topic	updateTopicAttribute
Deleting all topic attributes	Topic	deleteTopicAttributes
Deleting a specified topic attribute	Topic	deleteTopicAttributeByName
Adding a subscription	Subscription	subscribe
Deleting a subscription	Subscription	unsubscribe
Creating a message template	Message template	createMessageTemplate
Creating message templates in batches	Message template	batchCreateMessageTemplate
Modifying a message template	Message template	updateMessageTemplate
Deleting a message template	Message template	deleteMessageTemplate

Key Operations Recorded by CTS