No, You can change it. Serializable isolation level provides integrity at
the cost of performance.
Suppose there is one transaction which is updating the record and there is
another that is only reading and if it doesnt matter which value it reads
(before commit or after commit) then would it be right to use serializable
isolation level for both.I would recommend serializable for the first and
less stricter isolation level for the second.
Oreilly book provides some tips on how to deal with these in its last
chapter(ejb 1.0)
It all depends upon the type of interaction of your client with the server.
========================
Regds
Ashwani Kalra
Aithent Technologies
India
=============================
-----Original Message-----
From: A mailing list for Enterprise JavaBeans development
[mailto:[EMAIL PROTECTED]]On Behalf Of Nitin Kulkarni
Sent: Tuesday, July 10, 2001 3:43 PM
To: [EMAIL PROTECTED]
Subject: Re: About synchronization
If I got you correctly, then are you trying to say that the default
isolation level is Serializable and if I change it then my data is at a
risk?
But then the question is, is this the default behavior? SOme people might
say that it is a performance it, but then isn't it the way we want the txns
to behave. I would not want the data which my txn is dealing with to be
touched by any other txn while I am working on it, right?
Nitin
-----Original Message-----
From: Ashwani Kalra [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, July 10, 2001 3:29 PM
To: [EMAIL PROTECTED]
Subject: Re: About synchronization
By specifying the isolation levels we tell how much the two transaction be
separated so that integrity of the data is maintained. Ultimately its upto
the data base how to support these functions.
Using Isolation levels introduces trade offs between performance and
consistency of the database.
You are right as developer I dont have to worry about if two transaction
simultaneouly updates one row. Weblogic either seializes the access or it
provides two instances then one of the transaction will be aborted by
database .
========================
Regds
Ashwani Kalra
Aithent Technologies
India
=============================
-----Original Message-----
From: A mailing list for Enterprise JavaBeans development
[mailto:[EMAIL PROTECTED]]On Behalf Of Nitin Kulkarni
Sent: Tuesday, July 10, 2001 3:13 PM
To: [EMAIL PROTECTED]
Subject: Re: About synchronization
HI
If EJB provides by default serialized access to the shared data then why do
we have isolation levels? Atleast the weblogic documentation says that
serialized access to ntity beans is provided.
Nitin
-----Original Message-----
From: Ashwani Kalra [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, July 10, 2001 3:06 PM
To: [EMAIL PROTECTED]
Subject: FW: About synchronization
Hi,
1.Ejb provides concurrent access to the data.No programming needs to be done
for that. But you should know how to use the transaction and isolation
levels.
2.Session beans by definition is not shared by any other client.After the
work is done , session bean is destroyed and its state is not shared by any
other client except the one having the reference.
Ashwani Kalra
Aithent Technologies
India
-----Original Message-----
From: A mailing list for Enterprise JavaBeans development
[mailto:[EMAIL PROTECTED]]On Behalf Of Wenhui Bai at YSD
Sent: Tuesday, July 10, 2001 2:22 PM
To: [EMAIL PROTECTED]
Subject: About synchronization
Hi all,
I am a novice with EJB. With regard to synchronization, I am in a muddle
now.
Are there anybody who could kindly get me cleared?
1. Do I need to consider the synchronization if I intend to modify the same
resouce from EJB?
2. Regarding synchronization, the mechanism of session bean and entity bean
is same?
Thanks in advance:-)
Wenhui
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