多项选择题
You are the Database Administrator （DBA） of your company. You execute the following statement on an Oracle 10g instance：
SQL> ALTER SYSTEM SWITCH LOGFILE；
Which two tasks are performed when the statement is executed？ （）
A. The DBWn process writes to the datafile.
B. Changes in the background process are recorded.
C. The log file is updated with the current SCN number.
D. The System Change Number （SCN） is recorded in the control file.
E. The changes to the listener configuration in the listener.ora file are recorded.
