Re: ShoppingCart has very bad locking

Posted by Adrian Crum-2 on
URL: http://ofbiz.116.s1.nabble.com/ShoppingCart-has-very-bad-locking-tp1591136p1591904.html

--- On Sat, 3/13/10, Adam Heath <[hidden email]> wrote:

> Adrian Crum wrote:
> > --- On Fri, 3/12/10, Adrian Crum <[hidden email]>
> wrote:
> >> Consistent random foreign key violations. Two
> records would
> >> get the same sequence number. Random in that
> different
> >> entities would be affected each time, and
> consistent in that
> >> it happens nearly every time.
> >>
> >> Try running five or more threads against it on a
> >> multi-processor machine.
> >
> > Oops, maybe those were primary key violations. Bottom
> line is, an exception was thrown because two records got the
> same sequence ID.
>
> I've created a test case that runs 100 threads, all trying
> to get 1000
> sequence values.  I then verify that I get 100,0000
> different values,
> and everything passes.
>
> Could it be that your multi-threaded wrapper ends up using
> different
> random delegators?  This would say that the locking
> issues lie in the
> retry loop, which isn't being run by my multi-threaded
> code, since the
> bank in each thread is the same, and synchronized handles
> that
> concurrency.

I modified the demo data loading code to make it multi-threaded, so I believe only one delegator is being used. I have the patch at work, so I can't take a look at it until Monday.