HI, Today, we upgrade a group MariaDB 10.1.22 to MariaDB 10.2.6, after upgade, start delay slave : change master to master_delay=86400 start slave and execute show all slaves status , Seconds_Behind_Master continue grow and Exec_Master_Log_Pos not change, please help confirm what cause lead this ? thanks. Slave_IO_Running: Yes Slave_SQL_Running: Yes * Exec_Master_Log_Pos: 367* Seconds_Behind_Master: 116072 Gtid_IO_Pos: 0-227-72846307321 Parallel_Mode: conservative SQL_Delay: 86400 SQL_Remaining_Delay: 83164 Slave_SQL_Running_State: Waiting until MASTER_DELAY seconds after master executed event after 5 minutes, Slave_IO_Running: Yes Slave_SQL_Running: Yes * Exec_Master_Log_Pos: 367* Seconds_Behind_Master: 116550 Gtid_IO_Pos: 0-227-72846546131 Parallel_Mode: conservative SQL_Delay: 86400 SQL_Remaining_Delay: 82686 Slave_SQL_Running_State: Waiting until MASTER_DELAY seconds after master executed event