Deadlock victim while concurrent users...

Question

Hello-
I'm using Weblogic 6.1 SP3 and SQL Server 2000. In our application user create
packages...When concurrent users click at the same time to create the package,
application gets an error.
Create Package Functionality Overview: we've got the table called pt_package(package_id,
package_name, create_date, user_id). it has got relevant entity bean(PackageBean)
and we call ejbCreate...that go into the table and generete the maximum id and
then assign/create the package and write the details to the table.
Err Clip from console:
PackageBean : ejbCreate : java.sql.SQLException: [Microsoft][SQLServer 2000 Driv
er for JDBC][SQLServer]Transaction (Process ID 69) was deadlocked on lock resour
ces with another process and has been chosen as the deadlock victim. Rerun the
t
ransaction.
Created Package Id : 3175
====> InterviewSession: createUniquePackage Remote Exception..
java.rmi.RemoteException: EJB Exception:; nested exception is:
javax.ejb.EJBException: ejbCreate: [Microsoft][SQLServer 2000 Driver for
JDBC][SQLServer]Transaction (Process ID 69) was deadlocked on lock resources
wi
th another process and has been chosen as the deadlock victim. Rerun the transac
tion.
javax.ejb.EJBException: ejbCreate: [Microsoft][SQLServer 2000 Driver for JDBC][S
QLServer]Transaction (Process ID 69) was deadlocked on lock resources with anoth
er process and has been chosen as the deadlock victim. Rerun the transaction.
at ejb.entity.Package.PackageBean.ejbCreate(PackageBean.java:173)
at ejb.entity.Package.PackageBean_sf9ki2_Impl.ejbCreate(PackageBean_sf9k
i2_Impl.java:197)
at java.lang.reflect.Method.invoke(Native Method)
at weblogic.ejb20.manager.DBManager.create(DBManager.java:519)
at weblogic.ejb20.manager.DBManager.remoteCreate(DBManager.java:489)
at weblogic.ejb20.internal.EntityEJBHome.create(EntityEJBHome.java:190)
at ejb.entity.Package.PackageBean_sf9ki2_HomeImpl.create(PackageBean_sf9
ki2_HomeImpl.java:116)
at ejb.session.InterviewSessionBean.createUniquePackage(InterviewSession
Bean.java:2035)
at ejb.session.InterviewSessionBean_834tdn_EOImpl.createUniquePackage(In
terviewSessionBean_834tdn_EOImpl.java:4856)
at ejb.session.InterviewSessionBean_834tdn_EOImpl_WLSkel.invoke(Unknown
Source)
at weblogic.rmi.internal.BasicServerRef.invoke(BasicServerRef.java:305)
at weblogic.rmi.internal.BasicServerRef.handleRequest(BasicServerRef.jav
a:274)
at weblogic.rmi.internal.BasicServerRef.dispatch(BasicServerRef.java:167
at weblogic.rmi.internal.ServerRequest.sendOneWayRaw(ServerRequest.java:
92)
at weblogic.rmi.internal.ServerRequest.sendReceive(ServerRequest.java:11
2)
at weblogic.rmi.internal.BasicRemoteRef.invoke(BasicRemoteRef.java:136)
at weblogic.rmi.internal.ProxyStub.invoke(ProxyStub.java:35)
at $Proxy174.createUniquePackage(Unknown Source)
at jsp_servlet._ppro._interview.__sitecheck._jspService(__sitecheck.java
:192)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:27)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubIm
pl.java:265)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubIm
pl.java:200)
at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppSe
rvletContext.java:2546)
at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestIm
pl.java:2260)
at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:139)
at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120)
If you have any idea abt this, please let me know. I read bea documents, where
it says its due to insufficient number of connection. But I'm not very positive
abt it. Cause we conducted the test on our develeopement server as we had initial
5 connection and 15 as a max number of connection. We were only 4 person to test
that...Still we got the same err.......???
Thanx,
Ashish

Answer 1

Ashish wrote:
Hello-
I'm using Weblogic 6.1 SP3 and SQL Server 2000. In our application user create
packages...When concurrent users click at the same time to create the package,
application gets an error.
Create Package Functionality Overview: we've got the table called pt_package(package_id,
package_name, create_date, user_id). it has got relevant entity bean(PackageBean)
and we call ejbCreate...that go into the table and generete the maximum id and
then assign/create the package and write the details to the table.
Err Clip from console:
PackageBean : ejbCreate : java.sql.SQLException: [Microsoft][SQLServer 2000 Driv
er for JDBC][SQLServer]Transaction (Process ID 69) was deadlocked on lock resour
ces with another process and has been chosen as the deadlock victim. Rerun the
transaction.
If you have any idea abt this, please let me know. I read bea documents, where
it says its due to insufficient number of connection. But I'm not very positive
abt it. Cause we conducted the test on our develeopement server as we had initial
5 connection and 15 as a max number of connection. We were only 4 person to test
that...Still we got the same err.......???Hi Ashsish. This Exception is coming directly from the DBMS itself, and has nothing to do
with weblogic. The issue is a DBMS deadlock, where one DBMS client has locked some
page or database resource (let's call it resource A), and is going to try to lock some other
resource B. Some other DBMS client has already locked resource B, and now wants
to lock resource A. These two DBMS clients are deadlocked, and the DBMS recognises this,
and chooses to kill one client's transaction in order to at least let the other survive.
You should go over your tranasaction logic and DBMS locking to identify the locks
involved in the deadlock, and then decide if you can alter your logic to ensure that
every transaction locks A first, then B. It may also be an artifact of page-level locking,
where one tx may inadvertantly lock logically unrelated data, just because it is on the
same page as the logically relevant stuff.
Joe Weinstein.
>
>
Thanx,
Ashish