Exam 1z0-062 topic 1 question 176 discussion

An incremental checkpoint is a type of thread checkpoint partly intended to avoid writing large numbers of blocks at online redo log switches. DBW checks at least every three seconds to determine whether it has work to do. When DBW writes dirty buffers, it advances the checkpoint position, causing CKPT to write the checkpoint position to the control file, but not to the data file headers.

Both A and B are incorrect. Answer is CD: Incremental checkpoints An incremental checkpoint is a type of thread checkpoint partly intended to avoid writing large numbers of blocks at online redo log switches. DBW checks at least every three seconds to determine whether it has work to do. When DBW writes dirty buffers, it advances the checkpoint position, causing CKPT to write the checkpoint position to the control file, but not to the data file headers. https://docs.oracle.com/database/121/CNCPT/startup.htm#CNCPT1301

https://docs.oracle.com/database/121/CNCPT/startup.htm#CNCPT89045 An incremental checkpoint is a type of thread checkpoint partly intended to avoid writing large numbers of blocks at online redo log switches. DBW checks at least every three seconds to determine whether it has work to do. When DBW writes dirty buffers, it advances the checkpoint position, causing CKPT to write the checkpoint position to the control file, but not to the data file headers.

BD CKPT writes SCN in control file DBWn writes SCN in data files header

answer should be AD

https://saruamit4.wordpress.com/2014/11/01/checkpoint-scn/