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log file switch (checkpoint incomplete) event

From the AWR we can see what issue is more frequent:
a) DBWR has not finished checkpointing (log file switch (checkpoint incomplete) )
b) ARCH has not finished copying the redo log file to the archive destination (Archival required)
c) Wait event in session is log file switch (checkpoint incomplete).

The difference between log file switch completion and log file switch completion (Checkpoint Incomplete) wait event is, in the case of former wait event the users wait for the Log writer background process (LGWr) to complete its work (log switch). In the case of latter wait event the users wait for the Database Writer background process (DBWr) to complete its work (checkpoint).

Also be aware of the v$log_history view for showing the frequency of log switches.Redo log switching should occur approximately every 20-30 minutes to get better database performance.You should start with a minimum of 100 MB redo log files for any production database.

Brian Carr’s Article

The log file switch – checkpoint incomplete event tells you that Oracle wants to reuse a redo log file, but the current checkpoint position is still in that log file. This results in redo generation being stopped until the log switch is done. Obviously not good!

Recommendation:
To resolve these incomplete checkpoints you need to give the checkpoint process more time to cycle through the logs by doing one or both of the following:

* increase the size of the redo logs
* add more redo log groups

Additionally, consider turning off logging for the temporary tables with transient data using the the NOLOGGING attribute on the tables.

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