Dhanasekar, October 12, 2012 - 11:10 am UTC
Thank you for your reply.
But here i would like to know that the block sent to the node B will still have the data updated by node A but not committed.
If yes, So after sending the block to node B, if node A commits the changes it made, how the changes will be recorded in the block.
October 12, 2012 - 11:25 am UTC
the changes are already recorded in the block. When A made the change - it modified the block.
When A commits - all we do is update the undo segment to indicate that A committed - we do not in general revisit the block. We do not have to revisit the block for sure.
A commit does not have to revisit the blocks that were modified to say "we are done". The commit just ends the transaction and we record that in the undo segment. That is all.
That is true in RAC, that is true in single instance.
A reader, October 12, 2012 - 12:58 pm UTC
Thank you for your Clarification.
Dhanasekar, October 12, 2012 - 1:01 pm UTC
Thank you very much for the Clarification. I am now comfortable on Cache Fusion concepts.
OBJECT REMASTERING IN RAC
A reader, May 13, 2013 - 7:44 am UTC
hi, master tom:
i hava a question all the time about resurce master of oracle rac concept,i read a post internet,the detail is:
"In RAC, every data block is mastered by an instance. Mastering a block simply means that master
instance keeps track of the state of the block until the next reconfiguration event (due to instance
restart or otherwise)."
my question is:
when the rac decide which instance is the master of a data block?
whether once the rac instances starting,all the data blocks of all the datafile is sure belong to the instance ?
May 13, 2013 - 1:08 pm UTC
the master of a block is determined by a hashing algorithm on the data block address of the block.
the blocks within a datafile would be mastered by any or all of the instances in the cluster. it is not done by datafile.
OBJECT REMASTERING IN RAC
A reader, May 14, 2013 - 3:43 am UTC
thanks very much,tom!
i am from china,you know,although i work hard now in china and it is difficulty to buy house,i hope to work in america,can you help me?
blob
Willy Johnson, June 12, 2013 - 10:15 pm UTC
how to create a view from a table where you see all
fields but does not allow download the file
blob of a field from this table
June 18, 2013 - 3:10 pm UTC
Unless I'm missing something - you would just create a view that selects all of the columns except for the blob.
If you are trying to ask "can the database prevent the end user from doing something with the data they are allowed to select" - the answer to that is "of course not, they are allowed to see it". If they have select on that blob column - they can do whatever they want with it - the database just gives them the data, the database cannot prevent them doing things with it once their program has it.