Hi,

I have a configuration with hibernate running in Websphere 5.1 and jdk 1.4 for mapping a db2 database.
I'm using a load with LockMode.UPGRADE to lock the line. I'm doing this to get a key from a database without a sequence. It works with Hibernate 3.0 and generate a request SQL like "select ... for update with rr"

I upgrade from Hibernate 3.0 to hibernate 3.1 and It stop working. (the line is not locked) and the request SQL is like "select ... for read only with rs".

I declared a new dialect extending db2dialect like this

public class ExOctavDB2Dialect extends DB2Dialect {
public String getForUpdateString() {
return " for update with rr";
}
}

and now it works.

I take a look at CVS repository and i've seen that
the file cvs: hibernate/Hibernate3/src/org/hibernate/dialect/DB2Dialect.java

Changed this line in version 1.34
FROM
return " for update with rr";
TO
return " for read only with rs use and keep exclusive locks";

with the label HHH-378, better LockMode.UPGRADE on DB2

It was changed in version 1.35
FROM
return " for read only with rs use and keep exclusive locks";
TO
return " for read only with rs";

with the label fixed broken db2dialect

I think the rollback from version 1.35 to version 1.34 is not well done.

I think it should go in issue tracking but I want to ask you before polluting your jira.

Thank you

Kefah

Added 13/02/2006 Can somebody reply to my topic please ?

Hi kefah,
I think the problem is that the option to lock a row is hardcoded in the given method (getForUpdateString()). DB2 supports a lot of transaction serialization levels. The level 'rr' (repeatable read) tries to set a lock on the table and is not what we want. The level 'cs' (cursor stability) is better suited.
So it should be a good idea to set this option depending on the configured transaction serialization level.
Maybe Gavin would like so kind to make a little refactoring to that method and introduce a parameter (int serializationLevel) to choose the option according to the given parameter value.
regards Lutz
ps. Here a link to the DB2 documentation
http://publib.boulder.ibm.com/infocente ... /index.jsp
The isolation levels are contained within the manual 'SQL Reference'

Hi Lutz,

I'm happy to see that my problem interests someone.

I understand your needs and I think you're right about the new parameter because there is not only one way to lock a row in sql.

I solve my problem by extending the DB2Dialect and redefinied the getForUpdateString(). Then I referenced the new dialect in hibernate-cfg.xml.

I don't think this solution will help you solve your problem but I don't get ANY answer from Hibernate Dev Team and that's why I went for this solution.

Good luck for your problem and hope it will help you