SCN at particular time (Oracle database)

Asked By anonymous 7060 points N/A Posted on - 03/07/2012

Hi,

Please can anybody tell me that how we can get SCN at a particular time of a  database.?

Please advice.

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• Question Category: Oracle Database

Best Answer by Sharath Reddy

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Answered By Soriano Xone 0 points N/A #82589

SCN at particular time (Oracle database)

System Change Number also known as SCN is an increasing number.  It is an Oracle's clock, whenever a transaction is committed, it incremented.

 However it is not possible to know the System Change Number that corresponds to the same transaction because the SCN is committed after the transaction.

 I guess the best thing that you can do is get or grab the SCN immediately after you commit.  In addition to that, a commit does not write data files and it does not update or control files.  Moreover, flashblack can never recall any uncommitted work even you own.

I Hope this helps.

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• Posted on - 03/15/2012
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Answered By Sharath Reddy 590495 points N/A #82590

SCN at particular time (Oracle database)

In database, SCN stands for System Change Number. It is the chief means of maintaining data regularity or consistency in Oracle database. Here are some of the areas where you can use SCN:

• There is an SCN version in every redo record in the redo header. This also means that redo records may contain non-unique SCN version.
• Each data block contains block SCN and the block SCN is known also as block version.​
• SCN is used as well in read consistency. Each query made in the database contains query environment that contains SCN at the beginning of the query.
• Each commit generates an SCN which is known as commit SCN. It marks the limit of the transaction.

An SCN is composed of 2 components, the Base and the Wrap.

The Wrap component is a 16-bit number while the Base component is 32-bit.

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• Posted on - 05/03/2013
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Answered By carson fernandez 0 points N/A #82591

SCN at particular time (Oracle database)

Hello Techyv experts, as always your advise is genius and it goes without saying. So thanks, to both of you especially to Sharath for giving excellent performing answers. He is providing some areas in how to use and access SCN easily. Indeed, I am a complete layman about the areas where I can use SCN. After studying your free and easy comments I have achieved my desired information which I have mentioned in my question. Thanks from the core of my heart guys again as well also grateful to Techyv.com for giving space to post this.

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• Posted on - 08/25/2013
• Question Category: Oracle Database