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Locking of two sessions [message #552691] Fri, 27 April 2012 06:17 Go to next message
manjumagesh
Messages: 1
Registered: April 2012
Junior Member
Want to know how to avoid oracle deadlock with two sessions. Here is my example, We use Select query with For Update in order to get the unique number from a table. When one user has accessed this query, while the other user tries, System gives a Performace slow and when checked it is due to locking of this select query with For update.

We don't want to use For update WAIT or FOR UPDATE NOWAIT since these will result in missing of number.

Kindly suggest me.

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Re: Locking of two sessions [message #552692 is a reply to message #552691] Fri, 27 April 2012 06:20 Go to previous messageGo to next message
Michel Cadot
Messages: 68641
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
There are only 2 options: either you lock and wait, either you don't lock and don't wait.
Which one do you want?

By the way, there is a major difference between wait on lock and dead lock, do you know it?

Regards
Michel

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Re: Locking of two sessions [message #552698 is a reply to message #552691] Fri, 27 April 2012 07:17 Go to previous messageGo to next message
John Watson
Messages: 8929
Registered: January 2010
Location: Global Village
Senior Member
How about using 
select ... from ... for update skip locked;

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Re: Locking of two sessions [message #552700 is a reply to message #552698] Fri, 27 April 2012 07:24 Go to previous message
cookiemonster
Messages: 13920
Registered: September 2008
Location: Rainy Manchester
Senior Member
How would for update wait result in missing a number?

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