This will write all dirty buffers to disk so that when you run DBCC DROPCLEANBUFFERS, you can be assured that all data buffers are cleaned out.
To remove all the data from the buffers. This is useful to run between performance tests to ensure accurate testing results. This command only removes clean buffers.
Clears out the stored procedure cache for all SQL Server databases.
DBCC ERRORLOG: Rarely restarting the SQL Server service can cause the server log to get very large and take a long time to load and view. This can be truncated (essentially creating a new log) by running DBCC ERRORLOG. Consider scheduling a regular job that runs this command once a week. The same thing can be done using sp_cycle_errorlog.