log file switch (checkpoint incomplete)

The log file switch (checkpoint incomplete) wait event has no wait parameters. In Oracle Database 10 g , this wait event falls under the Configuration wait class. Keep the following key thought in mind when dealing with the log file switch (checkpoint incomplete) wait event.

Excessive log switches caused by small log files and a high transaction rate

Common Causes, Diagnosis, and Actions

The log file switch (checkpoint incomplete) and the log file switch completion are closely related and share the same root cause ‚ that is, the log files are too small for the amount of redo entries that are generated. When you see one, you normally see both in the database. However, in this case, the foreground processes are waiting on the DBWR process instead of the LGWR process. This happens when the application produces enough redo entries to cycle through or round- robin the redo logs faster than the DBWR process can write out the dirty blocks to complete a checkpoint. The LGWR process cannot overwrite or wrap into the first log because the checkpoint is incomplete, so foreground processes wait on the log file switch (checkpoint incomplete) event. The solution is the same as for the log file switch completion event. You need to replace the current log files with larger ones, and you may also add more log groups.