标签:ever answer redo log 正在执行 about back lgwr 考试题 执行
Which two are true about LGWR?A)LGWR always writes to the redo logs each time a COMMIT occurs.
B)LGWR always writes to the redo logs each time a ROLLBACK occurs.
C)LGWR never writes a single COMMIT to the redo logs.
D)LGWR may write to the redo logs when DBWR writes a dirty buffer.
E)Multiple COMMITs can be written by LGWR in the same write request.
F)LGWR always writes to the redo logs when DBWR writes a dirty buffer.
Answer: DE
赵:AF=>DE
冉:
DE 两个答案更妥,D 比 F 要好,因为 D 答案用了 may 没有用 always
E 答案给的是 group commit 的概念,即在 lgwr 正在执行时,其他会话发生的 commit 可以做为一组,随后一起提交。
标签:ever answer redo log 正在执行 about back lgwr 考试题 执行
原文地址:https://blog.51cto.com/13854012/2426628