how to check what causing replication full in Galera?

Hi all,

In case production incident, found replication is full by checking status variable "wsrep_flow_control_active". But we don't know what to check further.

More than 50% chance the replication will be resumed within 15mins. However, we have several cases that replication is not resumed after 3 hours.

In case of replication not resumed long time, re reboot the DB node to get service resume.

Understand the problem may be caused by additonal workload transaction. But we want to check further. Anything we can check in next occurance?

Regards,
William Wong