? ? 1? ? ? +DATADG01/gyl/archivelog/2014_10_23/thread_1_seq_11.270.861730475? ? 49.9980469
? ? 1? ? ? +DATADG01/gyl/archivelog/2014_10_23/thread_1_seq_12.271.861730509? ? 49.9980469
? ? 1? ? ? +DATADG01/gyl/archivelog/2014_10_23/thread_1_seq_13.272.861730545? ? 49.9980469
? ? 1? ? ? +DATADG01/gyl/archivelog/2014_10_23/thread_1_seq_14.274.861730573? ? 49.9980469
? ? 1? ? ? +DATADG01/gyl/archivelog/2014_10_23/thread_1_seq_15.275.861730601? ? 49.9980469
? ? 1? ? ? +DATADG01/gyl/archivelog/2014_10_24/thread_1_seq_16.276.861788401? ? 35.8242188
? ? 1? ? ? +DATADG01/gyl/archivelog/2014_10_24/thread_1_seq_17.278.861791005? ? 49.9980469
? ? 1? ? ? +DATADG01/gyl/archivelog/2014_10_24/thread_1_seq_18.279.861791039? ? 49.9980469
? ? 1? ? ? +DATADG01/gyl/archivelog/2014_10_24/thread_1_seq_19.281.861791071? ? 49.9980469
? ? 1? ? ? +DATADG01/gyl/archivelog/2014_10_24/thread_1_seq_20.282.861791091? ? 49.9980469
? ? 1? ? ? +DATADG01/gyl/archivelog/2014_10_24/thread_1_seq_21.283.861791119? ? 49.9980469
? ? 2? ? ? +DATADG01/gyl/archivelog/2014_10_23/thread_2_seq_2.269.861729571? ? 2.37207031
? ? 2? ? ? +DATADG01/gyl/archivelog/2014_10_23/thread_2_seq_3.273.861730551? ? .008300781
? ? 2? ? ? +DATADG01/gyl/archivelog/2014_10_24/thread_2_seq_4.277.861788403? ? .567871094
? ? 2? ? ? +DATADG01/gyl/archivelog/2014_10_24/thread_2_seq_5.280.861791047? ? .791503906
? ? 2? ? ? +DATADG01/gyl/archivelog/2014_10_24/thread_2_seq_6.284.861791125? ? .000976563
? （thread_1_seq_17至thread_1_seq_21为insert过程中节点1产生的归档，大小都接近redo file大小，thread_2_seq_5和thread_2_seq_6为节点2产生的归档，远小于redo file大小）
?SQL> select GROUP#,THREAD#,SEQUENCE#,STATUS,FIRST_CHANGE# from v$log order by 2;
? ? GROUP#? ? ? THREAD#? SEQUENCE#? ? ? STATUS? ? ? FIRST_CHANGE#
? ---------- ---------- ---------- ---------------- -------------
? ? ? 1? ? ? ? ? 1? ? ? ? 21? ? ? ? ? ACTIVE? ? ? ? 1206256
? ? ? 2? ? ? ? ? 1? ? ? ? 22? ? ? ? ? CURRENT? ? ? ? 1308608
? ? ? 3? ? ? ? ? 2? ? ? ? 7? ? ? ? ? CURRENT? ? ? ? 1338258
? ? ? 4? ? ? ? ? 2? ? ? ? 6? ? ? ? ? INACTIVE? ? ? 1014874
? （可以看到，节点2的FIRST_CHANGE#也跟进了，这里还超过了节点1的）? ? ?
? ? 再考虑一种极端情况，如果节点2已经down了，那么，节点2的归档将会由节点1进行代为执行，同样会推进节点2的redo log的FIRST_CHANGE#，继续上面的实验：?
--关闭节点2
?
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
--继续在节点1插入数据
begin
? for i in 1..500000 loop
? insert into darren values(1,'aa');
? commit;
? end loop;
end;
--??看归档情况和redo log 的FRIST_CHANGE#
SQL> select thread#,ARCHIVAL_THREAD#,name,blocks*block_size/1024/1024 "size" from v$archived_log order by 1,2;
? THREAD# ARCHIVAL_THREAD#? ? ? ? ? ? ? ? ? ? ? ? ? ? ? NAME? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? size
---------- ---------------- ---------------------------------------------------------------------- ----------
? ? 1? ? ? ? ? 1? ? ? ? ? ? +DATADG01/gyl/archivelog/2014_10_23/thread_1_seq_10.268.861729569? ? 1.4453125
? ? 1? ? ? ? ? 1? ? ? ? ? ? +DATADG01/gyl/archivelog/2014_10_24/thread_1_seq_18.279.861791039? ? 49.9980469
? ? 1? ? ? ? ? 1? ? ? ? ? ? +DATADG01/gyl/archivelog/2014_10_24/thread_1_seq_27.291.861795885? ? 49.9980469
? ? 1? ? ? ? ? 1? ? ? ? ? ? +DATADG01/gyl/archivelog/2014_10_24/thread_1_seq_26.290.861795861? ? 49.9980469
? ? 1? ? ? ? ? 1? ? ? ? ? ? +DATADG01/gyl/archivelog/2014_10_24/thread_1_seq_25.289.861795837? ? 49.9980469
? ? 1? ? ? ? ? 1? ? ? ? ? ? +DATADG01/gyl/archivelog/2014_10_24/thread_1_seq_24.287.86179