Re: ShoppingCart has very bad locking

Posted by Adam Heath-2 on
URL: http://ofbiz.116.s1.nabble.com/ShoppingCart-has-very-bad-locking-tp1591136p1591908.html

Adrian Crum wrote:

> --- 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.

Heh.  I run screen, so when I go home, I can just connect back to
work, and have everything immediately available.

All remote machines I connect to I immediately install screen.  So,
when I have to continue client work from home, I can also resume
wherever I was last at.

My laptop at home has been logged in to work since Feb. 21, without
disconnecting.

Could it be the sub sequence logic that is broken?