LockingService and rpc on the same cluster, tryLock() hangs

Hi,

Yes, the sequence diagram only depicted the second part of my description.

Anyway, I've attached a test file that reproduce the problem.

It contains two test cases, one where the coordinator of the lock is the one who
sends the message first, and a second case where the non-coordinator sends
the message first.

In the first case the receiver, non-coordinator, will hang in tryLock. In the second
case though, everything works fine.

Regards,
Daniel Olausson

On 25 March 2013 16:15, Bela Ban <belaban@yahoo.com> wrote:

Hi Daniel,

the sequence diagram differs from your description, can you submit a
test case (e.g. copy MessageDispatcherRSVPTest and modify it), so I can
take a look ?

I assume your RPCs are blocking (sync) and non-OOB ? Could be a
recursive invocation, where FIFO order (default) leads to a distributed
deadlock.

A test case would clarify what you want to do, and if I can reproduce
the problem, I can fix it.

On 3/25/13 1:54 PM, Daniel Olausson wrote:
> Hi,
>
> We trying to use the same channel for our lockingService and
> rpcDispatcher. But we are noticing some weird behavior.
>
> The end result is that lock.tryLock(lockName) never returns, which it
> should always do.
>
> This happens when we do the following:
>
> On computer A, we lock the lock.
> Do a rpc to a function on computer B, this function tries to take the
> lock(lock.tryLock(lockName)), but it can't because the lock is locked.
> This is correct behavior.
> Computer A unlocks the lock.
>
> On computer B we now do the same procedure, we lock the lock and do a
> rpc to computer A, but here is when the strange thing happens. Computer
> A tries to take the lock by executing tryLock, but it never returns.
>
> Here is a sequence diagram:
> http://www.websequencediagrams.com/cgi-bin/cdraw?lz=dGl0bGUgQXV0aGVudGljYXRpb24gU2VxdWVuY2UKCkNoYW5uZWwgMSAtPiAABAk6IGNlbnRyYWxMb2NrLnRyeUxvY2soKQAiDS0-KwAoCTI6IHJwY0Rpc3BhdGhlci5jYWxsbWV0aG9kKCJmb28iKQBfCTIAXAwyAFAYbm90ZSByaWdodCBvZiAiAF4JIjogAIEECSBibG9ja3MgZm9yZXZlcgBWDC0-LQCBQAxmb28gcmV0dXJucwoK&s=default
>
>
> In this example we use the standard udp.xml with <CENTRAL_LOCK/> added
> on the top of the stack. Everything works if we use PEER_LOCK but then
> we need the messages to arrive in the same order everywhere, e.g. atomic
> broadcast.
>
> It also works if we use different clusters for locking and rpc, but it
> would be convenient if we could use the same cluster.
>
>
> Is it recommended to use the same channel for different services?
>