“Log file switch (checkpoint incomplete)” waiting events are seen in v$session_wait, and AWR report. This event is caused normally by :
1) Redo log files are too small.
2) More redo groups are needed.
3) Disk I/O is not fast enough.
Normally this issue can be addressed through adding more redo groups and/or increasing redo log file size.
Oracle recommends no more than five log switches per hour.