[infinispan-dev] RejectedExecutionException

[David M. Lloyd]

On 06/12/2010 10:36 PM, Sanne Grinovero wrote:
> Hello,
> I've noticed the forum post about the RejectedExecutionException
> experienced under load [1]. In Hibernate Search we had a similar issue
> where the producers where quicker than the consumption of tasks; while
> I agree about defining a larger queue it's still possible to
> experience the error.
> What we did there is to customize the ThreadPool factory to have the
> caller block waiting for space in the queue when it's full [2].
>
> This seems to me a sane approach, not sure why there's no such policy
> by default in j.u.concurrent. am I missing something obvious?

I have implemented this same policy in the same way, however I abandoned 
this solution when I discovered subtle problems which occur in certain 
cases where there's work in the queue and suddenly no threads to run the 
work, or work is enqueued and the thread pool is below the max size, but 
the work sits in queue because no new thread is started to process it, or 
tasks are accepted after the thread pool is shut down (this is a problem if 
you take acceptance of a task to be any sort of guarantee that it will be 
executed; granted I see that in your example the ultimate fallback policy 
is to discard the task in case of interruption, a policy I happen to 
disagree with because of the indeterminate results that it may cause).

In the end, I decided that TPE was just not designed to solve this problem 
in this way, so for JBossAS 6+ I ended up writing an alternative thread 
pool implementation for the specific case where you want the caller to block.
-- 
- DML ☍