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From John Omernik <j...@omernik.com>
Subject Re: Failure Behavior
Date Sat, 26 Mar 2016 17:03:01 GMT
Thanks for the responses.. So, even if the drillbit that died wasn't the
foreman the query would fail? Interesting... Is there any mechanism for
reassigning fragments? *try harder* so to speak?  I guess does this play
out too if I have a query and say something on that node caused a fragment
to fail, that it could be tried somewhere else... So I am not trying to
recreate map reduce in Drill (although I am sorta asking about similar
features), but in a distributed environment, what is the cost to allow the
foremen to time out a fragment and try again elsewhere. Say there was a
heart beat sent back from the bits running a fragment, and if the heartbeat
and lack of results exceeded 10 seconds, have the foremen try again
somewhere else (up to X times configured by a setting).  I am just curious
here for my own knowledge what makes that hard in a system like Drill.

On Sat, Mar 26, 2016 at 10:47 AM, Abdel Hakim Deneche <adeneche@maprtech.com
> wrote:

> the query could succeed is if all fragments that were running on the
> now-dead node already finished. Other than that, the query fails.
>
> On Sat, Mar 26, 2016 at 4:45 PM, Neeraja Rentachintala <
> nrentachintala@maprtech.com> wrote:
>
> > As far as I know, there is no failure handling in Drill. The query dies.
> >
> > On Sat, Mar 26, 2016 at 7:52 AM, John Omernik <john@omernik.com> wrote:
> >
> > > With distributed Drill, what is the expected/desired bit failure
> > behavior.
> > > I.e. if you are running, and certain fragments end up on a node with a
> > bit
> > > in a flaky state (or a bit that suddenly dies).  What is the desired
> and
> > > actual behavior of the query? I am guessing that if the bit was
> foreman,
> > > the query dies, I guess that's unavoidable, but if it's just a worker,
> > does
> > > the foreman detect this and reschedule the fragment or does the query
> die
> > > any way?
> > >
> > > John
> > >
> >
>
>
>
> --
>
> Abdelhakim Deneche
>
> Software Engineer
>
>   <http://www.mapr.com/>
>
>
> Now Available - Free Hadoop On-Demand Training
> <
> http://www.mapr.com/training?utm_source=Email&utm_medium=Signature&utm_campaign=Free%20available
> >
>

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