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From Mat Kelcey <matthew.kel...@gmail.com>
Subject is there a way to just abandon a map task?
Date Sun, 20 Nov 2011 21:31:48 GMT
Hi,

I have a largish job running that, due to the quirks of the third
party input format I'm using, has 280,000 map tasks. ( I know this is
far from ideal but it's it'll do for me )

I'm passing this data (the common crawl web crawl dataset) through a
visible-text-from-html extraction library (boilerpipe) which is
struggling with _1_ particular task. It's hits a sequence of records
that are _insanely_ slow to parse for some reason. Rather than a few
minutes per split it's took 7+ hrs before I started explicitly trying
to fail the task (hadoop job -fail-task). Since I'm running with bad
record skipping I was hoping I could issue -fail-task a few times and
ride over the bad records but it looks like there's quite a few there.
Since it's only 1 of the 280,000 I'm actually happy to just give up on
the entire split.

Now if I was running a map only job I'd just kill the job since I'd
have the output of the other 279,999. This job has a no-op reduce step
though since I wanted to take the chance to compact the output into a
much smaller number of sequence files ( I regret that decision now) As
such I can't just kill the job since I'd lose the rest of the
processed data (if I understand correctly?)

So does anyone know a way to just abandon the entire split?

Cheers,
Mat

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