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From Greg Trasuk <tras...@stratuscom.com>
Subject Re: Bug fixing
Date Mon, 25 Oct 2010 17:50:16 GMT

On Mon, 2010-10-25 at 12:15, Patricia Shanahan wrote:
> I've made some progress on one form of failure, a resource remaining 
> available after its lease was scheduled to expire.
> 
> If the test pauses, e.g due to an inserted Thread.sleep, between 
> creating the lease and probing it for the first time, the test passes. 
> The effect of either of these actions is to delay the probe until after 
> the lease has expired. Incidentally, hooking up to the Eclipse debugger 
> was very helpful in discovering this behavior. The first indication was 
> when I spent a few minutes investigating at a breakpoint, let it 
> continue, and the test passed.
> 
> If the test gets to the probe point before the lease is due to expire, 
> it goes into a polling loop. No matter how long it stays in the polling 
> loop, the lease does not expire. Somehow, the probe loop has the effect 
> of preventing expiration.
> 
What is the "probe code" ?  How exactly does it determine that the lease
is still alive?

> I would like to understand the rules for lease expiration. What actions 
> should extend a lease? 

lease.renew(long duration);


> Is the lease manager required to expire it on 
> schedule? (Even if it is not required to expire the lease I still need 
> to find out whether the non-expiration is deliberate design or due to a 
> bug.)

Do you mean the landlord (i.e. the grantor of the lease), or the
LeaseRenewalManager object (which automatically renews leases on behalf
of a lessor)?

The owner of the resource does not need to expire it on a time schedule;
it could expire the lease at some future point that is a convenient run
time (like the next time the service happens to be accessed). 
Conceptually, the lease is entirely for the convenience of the lessor;
expiry means that the client is no longer interested in the resource, so
the client's resource allocation can be freed.

In any case, specs would be at:

http://www.jini.org/wiki/Jini_Distributed_Leasing_Specification

Cheers,

Greg.

> 
> Can anyone point me to documentation or a tutorial that would help?
> 
> Thanks,
> 
> Patricia
> 
> 
> Patricia Shanahan wrote:
> > I've done a preliminary javaspace test:
> > 
> >      [java] # of tests started   = 259
> >      [java] # of tests completed = 259
> >      [java] # of tests skipped   = 3
> >      [java] # of tests passed    = 243
> >      [java] # of tests failed    = 16
> > 
> > The failures seem to fall into a few clusters. I'll start on one of them 
> > tomorrow.
> > 
> > Patricia
> > 
> > On 10/20/2010 1:44 PM, Jonathan Costers wrote:
> >> My vote would go to the "javaspace" test category.
> >> Last time I ran that one (250 or so tests IIRC) I got 16 failures.
> >>> On 10/19/2010 4:08 PM, Patricia Shanahan wrote:
> >>> Any votes on my next bug hunt? For example, are there bug reports in 
> >>> Jira
> >>> that really need to be fixed before the next release?
> > 
-- 
Greg Trasuk, President
StratusCom Manufacturing Systems Inc. - We use information technology to
solve business problems on your plant floor.
http://stratuscom.com


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