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What are the Isolation level and uses of it

 
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krbabu

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Joined: 20 Feb 2004
Posts: 57

PostPosted: Thu Feb 26, 2004 4:31 pm    Post subject: What are the Isolation level and uses of it
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Can anybody give an idea of isolation level and uses of it
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mdtendulkar

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Joined: 29 Jul 2003
Posts: 238
Location: USA

PostPosted: Thu Feb 26, 2004 5:01 pm    Post subject:
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Hello krbabu,

Maintaining database consistency and data integrity, while allowing more than one application to access the same data at the same time, is known as concurrency. One of the ways DB2 attempts to enforce concurrency is through the use
of isolation levels, which determine how data used in one transaction is locked or isolated from other transactions while the first transaction accesses it. DB2 uses the following isolation levels to enforce concurrency:

Repeatable Read
Read Stability
Cursor Stability
Uncommitted Read

For more details on the same, refer the following link

http://www2.tw.ibm.com/developerWorks/tutorial/pdf/db2cert6v8-a4.pdf

Hope this helps,

Regards
Mayuresh Tendulkar
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rachel

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Joined: 09 Mar 2005
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PostPosted: Thu Aug 25, 2005 5:47 pm    Post subject:
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Hi,


The contents of the tutorial are not in english.

icon_rolleyes.gif
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anadhamohan

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Joined: 27 Sep 2005
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Location: india

PostPosted: Wed Sep 28, 2005 11:09 am    Post subject:
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UR scans: No row locks are held unless row data is changing. It's Read-Only lock.
CS scans: Row locks are only held while the cursor is positioned on the row. Once the cursor moves from that row the lock will be released until the previous row is changed.
RS scans: Only qualifying row locks are held for the duration of the transaction. Others can able to view (or) insert rows to that page.
RR scans: All row locks are held for the duration of the transaction.
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Cathy123

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Joined: 07 Jul 2006
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Location: Chennai

PostPosted: Mon Mar 19, 2007 10:57 am    Post subject: Re: Isolation level
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Hi,

Are Isolation levels different types of Row locks?

Thanks,
Cathy
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vini_srcna

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Joined: 26 May 2005
Posts: 178
Location: Copenhagen, Denmark

PostPosted: Wed Mar 21, 2007 1:45 pm    Post subject:
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Isolation Level is different from Lock types.
Lock type (typically LOCKSIZE of ROW,TABLE,PAGE) says what kind of lock to hold.
It will be specified in the DDL of tablespace. I think it defaults to ANY which inturn says it ROW level locking.

Isolation level is to say How long to hold this lock. There are many articles on this concept.
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