SCN in the block ?

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Originally posted by SANJAY_G

Quote:

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Originally posted by sonia
sanjy, u were talking about blocking the dump...i just tried
that, but could not figure out to which path does it write to...can u just explain me abt the same...

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Sonia, blocking the dump or dumping the block :)
The trace file goes to user_dump_dest.

Sanjay

[Edited by SANJAY_G on 09-20-2002 at 05:25 AM]

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Hey sanjay.....it was a typO

Quote:

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Originally posted by Sonia

Quote:

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Originally posted by SANJAY_G

Quote:

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Originally posted by sonia
sanjy, u were talking about blocking the dump...i just tried
that, but could not figure out to which path does it write to...can u just explain me abt the same...

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Sonia, blocking the dump or dumping the block :)
The trace file goes to user_dump_dest.

Sanjay

[Edited by SANJAY_G on 09-20-2002 at 05:25 AM]

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Hey sanjay.....it was a typO

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O IC ;)

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Originally posted by virajvk
Dear sir

I am also wondering why SCN number is to be written to
data block in Datafile.

Normally all header information is getting updated due to
checkpoint process.
Checkpoint does synchronization and DBWR will write to datafile header

So Oracle Experts What is correct things
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Viraj
Oracle OCA

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Concept of block level SCN is just like our row level locking. It's about efficiency. Think like this, we have a system where each and every transaction updates our datafile headers thus resulting in synchronization of all of the block level SCNs. In this case Oracle will write very aggressivle for each and every transaction resulting in heavy use of CPU. To avoid this, we have different level of SCNs.
Block level SCN => just updates the changed block header. this happens during transaction
Check point SCN => updates all the block headers as well as datafile headers. this happens during check point.

So, in any typical system no. of SCN changes at block level are allways more than check poin SCNs.


(A transaction does not result in checkpoint)

I guess this will arguement will do alot to confuse others and stirr another 10 postings for this thread ;)