The checkpoint process(CKPT) is responsible for initiating check points. A check point is when the system periodically dumps all the dirty buffers to disk. Most commonly, this occurs when the database receives a shutdown command. It also updates the data file headers and the control files with the check point information so the SMON know where to start recovery in the event of a system crash.
CKPT进程是初始化checkpoint，而checkpoint的作用是让系统可以周期性地把“脏数据”更新到磁盘。