| Concurrency in Oracle [message #23423] |
Fri, 06 December 2002 07:24  |
prashant
Messages: 122
Registered: September 2000
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Senior Member |
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Hi all,
I just found out that if i issue two update statements on the same column of a table in 2 different sessions then one session hangs till i issue a rollback or commit in the other session. For eg i issued 2 statements as follows :
1 .update emp1 set sal = 2566 where deptno = 20 ;
2 .update emp1 set sal = 1500 where deptno = 20 ;
So here command one completes successfully but the second session hangs until i issue a commit or rollback in session 1.
This must be due to the locking techniques of Oracle and isolation levels etc. but what i want to know is whether this is the default behaviour in Oracle or can we change it. Also can somebody suggest me some good links on this topic for further reading.
Thanks a lot in advance
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| Re: Concurrency in Oracle [message #23424 is a reply to message #23423] |
Fri, 06 December 2002 08:38  |
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Mahesh Rajendran
Messages: 10707
Registered: March 2002
Location: oracleDocoVille
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Senior Member
Account Moderator |
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it is expected.
did you have a look in the oracle concepts manual
( look for transaction management techniques and concepts)?
and all oracle docs are free to view/download
at tahiti.oracle.com
and
technet.oracle.com/docs
all u need is a free membership
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