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。