Oracle checkpoint type

The CKPT type of the Oracle checkpoint is used to write the checkpoint to the control file and data file header. Check points are of the following types: Thread checkpoints is the database check point, which may occur in the following cases: closing the database consistently; alter systerm checkpoint statement; switching online redo log file; alter database begin backup statement; Tablespace and data file checkpoints refresh the dirty data blocks in the SGA of all data files in a Tablespace to the disk. This check point will appear in the following circumstances: make a tablespace read-only or offline normal; shrink a data file; alter database begin backup statement; Incremental checkpoints (Incremental BACKUP) DBWn refreshes dirty data blocks in SGA to physical files every three seconds, while CKPT sends a checkpoint every three seconds to write the checkpoint information to the control file, but does not update the data file header information. . Other checkpoints other checkpoints include those triggered when the instance is restored, or when the object is deleted or truncate.