Information on Lock Manager

tgore

tgore

Reputable Poster
I am trying to obtain more detailed information on Lock Manager. I got some information from JDE, but it just isn't working the way we expect. Sometimes the record gets locked and other times it does not. Here is one instance where it does not appear to work:

If the same user has two screens open that access a file, the lock manager does not issue an error message.

We tried implementing this in a very controlled environment on a Saturday. All users were prevented from logging in except our "test crew". We tried it with lock manager off and then implemented it per JDE instructions. Once our testing was complete, we turned the option back off.

Any assistance would be greatly appreciated.
 
tgore

Maybe I misunderstand what you are saying, but Lock Manager only =
operates at the record level, not the file level.

With dynamic record locking the chances of more than one user hitting =
the same record at the same point and at the time as anyone else is, to =
say the very least, extremely remote. I seem to recall Oracle claiming =
on OPS a likelihood of 10,000,000/1 of this occurring.

So, you may be seeing a problem other than a lock manager issue. I'm =
looking into what.

Sid Perkins
Independent Consultant
Tel: +44 (0)1304 825003
Mobile: +44 (0)7713158807
[email protected]
 
I used to be a "cheerleader" for lock manager.
After seeing all the performance problems it causes, I now recommend against it. Usually your database can take care of record locking and not allowing two users to update the same record at the same time. If you have a need outside of that, it can usually be addressed by some means other than Lock Manager.... Is there a specific reason for turning it on?

Jennifer Sharma, Sr. Technical Specialist
AELLIUS Professional Research & Consulting, LLC
www.aellius.com
 
We are trying to implement it because we are seeing occurances of file corruption due to multiple users accessing/updating the same record at the same time.

What we see happening is that user "A" views and updates record "1". User "B" is viewing record "1" while user "A" is viewing/updating. User "B" is not aware of the changes user "A" made so user "B" updates record "1". This results in a duplicate records.

When we turned on Lock Manager, user "B" received an error message stating that the record had changed since the last viewing. This would force user "B" to refresh the screen to be able to see the latest results.



Sid-I do not disagree with the information you supplied, but contrary to the "odds" Oracle gives, it is happening here quite often.
 
I re-read your original post, and I should point out that the functionality of Lock Manager won't necessarily issue a message just because two users are in a particular menu that opens the same file- but rather for two users who have the same record open and a change is made by one. If User A and User B both select a particular Address Book record, and one of the users updates something like the last name, the other user will receive the message that the record has been changed. If no one makes any changes to the record, then no message will be sent.
Many companies have resolved this, at least to an extent, by making sure there is a primary person for updating a given account, but sometimes it is not feasible to do so.

If you are not experiencing any performance impact from this, then I would say to continue testing it.

One thing that would help you, though, is to see if Peoplesoft can forward you the list of applications that have (or don't have) Lock Manager functionality. Most applications should have the functionality by now, but if you see a particular application for which you do a test and there is no message sent, then you may find that that particular application does not have the functionality.

Hope this helps...

Jennifer Sharma, Sr. Technical Specialist
AELLIUS Professional Research & Consulting, LLC
www.aellius.com
 
Thanks for your reply. Calling PeopleSoft is not an option. All of the applications are custom written. We are only using OW for a very small custom system that was needed here. We use World for everything else (addr book, sales, G/L, etc).

I will continue my quest to see what other options are available. Thanks again.
 
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