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Home -> Community -> Mailing Lists -> Oracle-L -> Re: Split Blocks on Instance Crash
Hi Tanel,
Very sorry - I'm being slow today - I still don't get it! Why can you always read the previous image of the block from disk? The hypothesis was that DBW was in the middle of writing when the instance crashed, leaving only a current copy of the block on disk - a split one since DBW did not complete the write.
Thanks
Charlotte
>Hi,
>
>Because in case of instance crash, you can always
read the previous image of
>block from disk and all subsequent changes to this
block can be read from
>online logfiles, in media failure case you might not
be able to do so.
>
>Tanel.
>
>----- Original Message -----
>From: "Charlotte Hammond"
>To:
>Sent: Thursday, December 22, 2005 9:31 AM
>Subject: Re: Split Blocks on Instance Crash
>
>
>>
>> Thanks David - but why is this different from the
>> backup situation? You would have the (archived)
redo
>> available then too, but you must still use
BEGIN/END
>> BACKUP to avoid split blocks.
>>
>> Charlotte
>>
>>
>>
>> --- David Sharples wrote:
>>
>>> because the information is available from redo /
>>> undo and can easily be
>>> replayed in case of a failure
>>>
>>> On 12/22/05, Charlotte Hammond
>>> wrote:
>>> >
>>> > Hi All,
>>> >
>>> > Why does instance crash recovery not encounter
the
>>> > split blocks that you might get doing a backup
>>> without
>>> > BEGIN/END BACKUP?
>>> >
>>>
>>
>>
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-- http://www.freelists.org/webpage/oracle-lReceived on Thu Dec 22 2005 - 18:02:52 CST
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