If a replication task starts after the TiCDC service starts, the TiCDC owner updates the PD service GC safepoint with the smallest value of checkpoint-ts among all replication tasks. The service GC safepoint ensures that TiCDC does not delete data generated at that time and after that time. If the replication task is interrupted, or manually stopped, the checkpoint-ts of this task does not change. Meanwhile, PD’s corresponding service GC safepoint is not updated either.
If the replication task is suspended longer than the time specified by gc-ttl, the replication task enters the failed status and cannot be resumed. The PD corresponding service GC safepoint will continue.
The Time-To-Live (TTL) that TiCDC sets for a service GC safepoint is 24 hours, which means that the GC mechanism does not delete any data if the TiCDC service can be recovered within 24 hours after it is interrupted.