[infinispan-dev] Let me understand DIST

[Bela Ban]

On 3/15/12 3:42 PM, Pedro Ruivo wrote:

> 4 nodes, N1 to N4.
> N2 is the primary owner of KeyA.
> N3 is the primary owner of KeyB.
> N1 is executing the transaction Tx1 which writes in A and B
> N4 is executing the transaction Tx2 which writes in A and B.
> Both transactions try to prepare at the same time. This scenario can
> occurs (I think):
>
> N2 ->  deliver(Tx1), lock(KeyA), deliver(Tx2), tryLock(KeyA) //Tx2 is
> blocked until the lock of KeyA is released
> N3 ->  deliver(Tx2), lock(KeyB), deliver(Tx1), tryLock(KeyB) //Tx1 is
> blocked until the lock of KeyB is released
>
> Eventually Tx1 or Tx2 (or both) will be aborted by a timeout. Is this
> behavior correct? Am I missing something?


This is correct, and shows why we have collisions (deadlocks and then 
backoffs) with our current 2PC scheme...


-- 
Bela Ban, JGroups lead (http://www.jgroups.org)