In a Nutshell

In this chapter, we equipped you to deal with wait events that are related to user comments, log buffer, DBWR process, and log files. They are the log file sync, log buffer space, free buffer waits, write complete waits, log file switch completion, and log file switch (checkpoint incomplete) wait events.

The log file sync wait event is related to transaction terminations such as commits or rollbacks .

The log buffer space wait event is related to the log buffer. Sessions wait on the log buffer space event when they are unable to copy redo entries into the log buffer due to insufficient space.

The free buffer waits event is related to the LRU list and DBWR process. Sessions wait on the free buffer waits event when they are unable to find a free buffer on the LRU list or when all buffer gets are suspended .

The write complete waits event has to do with blocks that are presently being written out by the DBWR process.

The log file switch completion and log file switch (checkpoint incomplete) is due to high log file switch frequency.