[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-1512) Problem to lock a row in a DB2 database with LockMode UPGRADE

[Steve Ebersole (JIRA)]

    [ https://hibernate.onjira.com/browse/HHH-1512?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=46435#comment-46435 ] 

Steve Ebersole commented on HHH-1512:
-------------------------------------

In reference to my last comment, this specific DB2 documentation is @ http://publib.boulder.ibm.com/infocenter/dzichelp/v2r2/index.jsp?topic=%2Fcom.ibm.db2z10.doc.sqlref%2Fsrc%2Ftpc%2Fdb2z_sql_readonlyclause.htm

Especially note:
{quote}
To take advantage of the possibly improved performance of FETCH operations while guaranteeing that selected data is not modified and preventing some types of deadlocks, you can specify FOR READ ONLY in combination with the optional syntax of USE AND KEEP ... LOCKS on the isolation-clause.
{quote}

Again, keeping in mind that "selected data is not modified" is specifically in regards to positioned updates.

> Problem to lock a row in a DB2 database with LockMode UPGRADE
> -------------------------------------------------------------
>
>                 Key: HHH-1512
>                 URL: https://hibernate.onjira.com/browse/HHH-1512
>             Project: Hibernate ORM
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 3.1
>         Environment: DB2 v8.2, Hibernate 3.1 and higher
>            Reporter: Peter Potthoff
>            Assignee: Steve Ebersole
>             Fix For: 4.1.3
>
>         Attachments: locks.txt
>
>   Original Estimate: 1h
>  Remaining Estimate: 1h
>
> Using the LockMode UPGRADE to lock a row in the database, this will result in
> a sql-statement: select ID from <schema>.<table> where ID =? and version =? for read only with rs
> This statement produces a shared lock and cannot be used for pessimistic locking because
> this kind of lock won't stop a concurrent thread from accessing the data.
> The source of the class DB2Dialect.java was changed from release 1.34 to 1.35:
> http://cvs.sourceforge.net/viewcvs.py/hibernate/Hibernate3/src/org/hibernate/dialect/DB2Dialect.java?r1=1.34&r2=1.35
> and from 1.33 to 1.34
> http://cvs.sourceforge.net/viewcvs.py/hibernate/Hibernate3/src/org/hibernate/dialect/DB2Dialect.java?r1=1.33&r2=1.34
> Please take a look at: HHH-378 and http://forum.hibernate.org/viewtopic.php?t=954639&highlight=db2+lock+upgrade

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