单项选择题 You work as a database administrator for Certkiller .com. You find that the database performance degrades while you backup the Certkiller database using Recovery Manager （RMAN）. The Certkiller database is running in shared server mode. The database instance is currently using 60% of total operating system memory. You suspect the shared pool fragmentation to be the reason.  Which action would you consider to overcome the performance degradation？（）

单项选择题 YouworkasadatabaseadministratorforCertkiller.com.Youstartedtheinstanceusingtheinit.orafile.Youhavetwocontrolfilesandthreeredologgroupsinyourdatabase.Youdecidedtoprotectthedatabaseagainstfailuresbyaddingonemorecontrolfile.Whichfileistheappropriatewaytoperformthistask？（）

单项选择题 ThedatafilebelongingtotheSYSTEMtablespaceiscorruptedandnobackupofthefileisavailable.Howdoyourecoverthedatafile？（）