针对Flash Recovery Area删除文件不回收空间的问题诊断, 即在FRA下删除了文件但space未被回收的情况, 首先收集如下信息   ALERT LOG   select * from v$recovery_area_usage; select * from v$recovery_file_dest;   rman 收集: show all; catalog recovery area;   并收集以下TRACE: alter session set events 'immediate trace name kra_trace level 1'; execute dbms_backup_restore.refreshAgedFiles; alter session set events 'immediate trace name kra_trace level 4';