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Flume >> mail # dev >> EventDrivenSource and dead threads

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Re: EventDrivenSource and dead threads

Yes I can definitely see the issue. It sucks that we'd have to add yet
another thread. An alternative which wouldn't require another thread
would be to check the optional interface in the supervisor,
approximately here:


However, I am not sold on the supervisor being the best place to fix
this as I am not sure that other lifecycle components would need this.


On Wed, Jan 16, 2013 at 7:45 PM, Juhani Connolly
> I came upon an issue with ScribeSource,  though it's theoretically
> applicable to any EventDrivenSource whose event generating thread(s) die.
> Simple put, sending a bad packet to the thrift(scribe protocol) port will
> result in it trying to allocate space for some arbitrarily large packet
> resulting in an OOMException which kills the thread(incidentally I thought
> this would be an issue in avro too, but it throws an exception before making
> excessive allocation requests).
> As far as flume is concerned, the component is still alive. stop() was never
> called, so even monitoring the component state using jmx will not notice
> anything wrong. This situation occurs from user error, but there is
> potential for other errors leaving a zombie component. I think it would be
> more user friendly to be able to recover from such errors.
> I'm thinking of adding a StatusPollable interface that EventDrivenSources
> can optionally implement(because we can't change the interface without a
> version change). If implemented, the EventDrivenSourceRunner would schedule
> a regular poll to check the state. Upon failure it could either call stop()
> to signal it broke. With autoRestartPolicy, the source would then get
> restarted by its supervisor.
> Would appreciate any opinions before I put together a patch/post an issue.

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