单项选择题 Whichofthefollowingarchitecturesisusedtosupporttheagentortheapplicationtier？（）

单项选择题 You just completed a manual open database backup. However there seems to be a problem with the database performance. You discover that the database is generating many log switches and the LGWR is consuming lots of CPU time. You have an idea of what the problem is and you begin looking at the information in V$BACKUP and in V$DATAFILE_HEADER. What do you suspect is the problem？（）

单项选择题 Examine this statement：  RMAN >BACKUP FORMAT ’/BACKUP/df_%d_%s_%p.bus1 DATABASE filesperset = 2；  What state must the target database be in for you to use this RMAN command？（）