题目内容:
YourdatabaseinstanceisconfiguredwithautomaticundomanagementandtheUNDO_RETENTIONparameterissetto900seconds.Youexecutedthefollowingcommandtoenableretentionguarantee:SQL>ALTERTABLESPACEundotbs1RETENTIONGUARANTEE;Whateffectwouldthiscommandhaveonthedatabase()
A.Theextentsintheundotablespaceretaindatauntilthenextfulldatabasebackup.
B.Theextentscontainingcommittedundointheundotablespacearenotoverwrittenforatleast15minutes.
C.Theextentscontainingcommitteddataintheundotablespacearenotoverwrittenuntiltheinstanceisshutdown.
D.TheextentscontainingcommittedundointheundotablespacearetransferredtoFlashRecoveryAreabeforebeingoverwritten
参考答案: