| the way about rac recovery [message #307492] |
Wed, 19 March 2008 00:37  |
alantany
Messages: 115
Registered: July 2007
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Senior Member |
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Hi,all
I am very confused with the way oracle does a RAC recovery.
For I have a 2 nodes RAC .
10:00 user connect to node1(instance1 ) and execute
sql>insert into table t values(1);
sql>commit;
10:30 user connect to node2(instance2 and execute:
sql>delete from t1;
sql> commit;
sql>alter system switch logfile.
now redo log belong to instance2 was archived with sequence 1000.
11:00 redo log belong to instance1 was archived with sequence 2000.
Now I want to recovery the database,how does oracle decide with archived log should be apply first?
If it choose the log by the time order ,here first is sequence 1000,and then 2000,but we can see,transaction at 10:00 should be apply first, but the time it was archived later than the other one.
Could someone gave a explain?
Hope I descript it clearly.
Regards!
Alan
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| Re: the way about rac recovery [message #307530 is a reply to message #307512] |
Wed, 19 March 2008 01:30  |
alantany
Messages: 115
Registered: July 2007
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Senior Member |
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Thanks Michel!
I have learned many things from you !
I still want a more detail clarity:
in my case:
is there exists this situation:
one archived log includes a transaction with scn1,and should be
appled,and includes other transaction with scn s3, should be appled
after the transaction on the other archived log with scn2 was appled.
that means:
archived log transactions scn
A t1,t3 s1 s3
B t2 s2
Here s1<s2<s3
does oracle:
1.first find the transaction with scn s1 on logfile A,apply it.
2.find the transaction with scn s2 on logfile B ,apply it.
3.find the transaction with scn s3 on logfile A again,apply it?
Could oracle apply archived log like this way?
your comments!
Regards
Alan
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| Re: the way about rac recovery [message #307554 is a reply to message #307547] |
Wed, 19 March 2008 02:06 |
alantany
Messages: 115
Registered: July 2007
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Senior Member |
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Hi,Michel
I still confused:(
I believe redo records in SCN order is distributed cross all the redo logs ,how does oracle get them in order? does oracle visit a log file many times?
I am sorry if you think this question s too simple.
Regards
Alan
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