Hi All,
We are using BlockingQueue in BalancedFlowController. I dont
see the
method poll but its possible its called internally by one of
the other
methods. This might be the issue we are seeing which makes
the cpu go
crazy after a day or so.
Just read the javadoc and we do call take.. The javadoc
say..
E take()
throws InterruptedException
Retrieves and removes the head of this queue, waiting if no
elements
are present on this queue.
Which is the same as poll, but poll have a timeout.
Regards,
Luke
On 11/23/06, Trustin Lee <trustin gmail.com> wrote:
> Just a heads-up though MINA isn't using the mentioned
method.
>
> HTH,
> Trustin
> ---------- Forwarded message ----------
> From: Holger Hoffstaette <holgerwizards.de>
> Date: Nov 23, 2006 1:30 AM
> Subject: Warning: serious VM leak/bug with
BlockingQueue & polling timeouts
> To: devdirectory.apache.org
>
> [sorry if this is a duplicate - the first one did not
seem to make it?]
>
> Here's a heads up for those of you who have the Mina
source handy to check.
>
> Both JDK 1.5 and 1.6 have serious confirmed bugs that
leak unreclaimable
> memory and will bring *idle* servers down, e.g. during
the night or over
> the weekend when load is low or nonexistent. For more
information see
> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=646
0501 and related.
>
> In a nutshell BlockingQueue.poll(duration, TimeUnit)
will leak *when that
> wait times out*; it will not leak when something is
returned from the
> queue, as is the case with uninterrupted non-timed
polling.
>
> The bug is confirmed and serious because it triggers
extremely nasty GC
> panic that has the potential to bring the whole machine
down due to
> excessive CPU spinning and unresponsiveness of the VM
to external signals.
>
> I think it would be good if someone with the source
would do a quick "find
> all references to method" to see if and how Mina
is affected by this. I
> would not be surprised if this is the reason behind
some reported leaks -
> polling with timeout is extremely useful for service
scheduling in various
> forms and generally preferrable to complete blocking.
>
> hope this helps 
> Holger
>
>
>
>
> --
> what we call human nature is actually human habit
> --
> http://gleamynode.net/
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>
>
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