You need to know that the data in your database is good and that the instance
is giving you all the information you need. This is why checkpoints were created.
The CKPT process is a coordinator process. CKPT works with the DBWR and LGWR processes to make sure that all the modified database buffers are written to disk and that the headers of the control files and redo log files are marked as current. At the end of a checkpoint, you know that all the modified buffers in the data buffer cache and the redo log buffer have been written to disk. This coordination is diagrammed below.
What causes a checkpoint?
You can force a checkpoint by issuing commands from SQL*Plus or Oracle SQL Developer, for example:
> alter system checkpoint local
> alter system checkpoint global
In other cases checkpoint events are automatically processed by normal events such as:
When a redo log file fills, the LGWR switches to another redo log file
If you have set LOG_CHECKPOINT_TIMEOUT (an init.ora parameter) and the specified interval has lapsed
If you have set LOG_CHECKPOINT_INTERVAL (an init.ora parameter) and the specified number of disk block have been written to the redo log files