Concurrency problems with optimistic locking

user100 · **Joined:** Fri Oct 17, 2003 12:40 pm **Posts:** 16

I problem with concurrency (optimistic locking). When userA deletes the record and userB updates it, I get an error. My problem is when userA updates the record and userB updates the record later, userB overrides the change made by userA. But I should get a StaleObjectError when userB updates the record.
I am using the technique mentioned in the reference document 14.3.2 (Many sessions with automatic versioning). I do use saveOrUpdate, then flush, commit and close. Is there any additional steps or am I doing anything wrong.

Thanks for your help.

steve · **Posted:** Fri Oct 17, 2003 3:50 pm

How are you implementing optimistic locking? Include your mapping file.

user100 · **Joined:** Fri Oct 17, 2003 12:40 pm **Posts:** 16

I think not. What should I add in the mapping file to implement optimistic locking. Thanks

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>
<class name="TestClass" table="table1">
<id name="Id" column="Primay_ID" type="long" unsaved-value="-1">
<generator class="sequence">
<param name="sequence">SEQUENCE_ID</param>
</generator>
</id>
<property name="Name" column="NAME" type="string"/>
<property name="Comments" column="COMMENTS" type="string"/>
</class>
</hibernate-mapping>

user100 · **Joined:** Fri Oct 17, 2003 12:40 pm **Posts:** 16

user100 wrote:

What should I add in the mapping file to implement optimistic locking. I am trying to implement optimistic locking using "Many Sessions with automatic versioning (14.3.2 in the reference doc). Thanks for your help.

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>
<class name="TestClass" table="table1">
<id name="Id" column="Primay_ID" type="long" unsaved-value="-1">
<generator class="sequence">
<param name="sequence">SEQUENCE_ID</param>
</generator>
</id>
<property name="Name" column="NAME" type="string"/>
<property name="Comments" column="COMMENTS" type="string"/>
</class>
</hibernate-mapping>

steve · **Posted:** Fri Oct 17, 2003 5:05 pm

Depends on what type of strategy you want to use. Check out the docos:
http://www.hibernate.org/hib_docs/reference/html/transactions.html#transactions-s3

emmanuel · **Posted:** Fri Oct 17, 2003 5:05 pm

user100 wrote:

I think not. What should I add in the mapping file to implement optimistic locking. Thanks

Add a version column to your table, and add this

Code:

<class...>
...
<version
        column="version_column"   
        name="version"       
        type="integer"           
/>
</class>

Read 4.1.7 section of the ref guide

micho2001 · **Posted:** Fri Oct 17, 2003 9:41 pm

You might also wanna check this out in case you encounter a dirty read or conflict:

http://hibernate.bluemars.net/hib_docs/api/net/sf/hibernate/StaleObjectStateException.html