# Key Operations Recorded by CTS

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

Parent topic: SMN Operation Recording