Hi Todd,
It was definitely working fine a week before and the code hasn't changed much.
On my laptop a pseudo distributed installation for the same code finishes
successive map reduce iteration quickly enough.
As far as I can see it, it is probably due to reformatting the fs. But I can't
understand why it occurs this way.
tx
Himanshu
Morpheus: Do you believe in fate, Neo?
Neo: No.
Morpheus: Why Not?
Neo: Because I don't like the idea that I'm not in control of my life.
________________________________
From: Todd Lipcon <t...@cloudera.com>
To: mapreduce-user@hadoop.apache.org
Sent: Tue, November 24, 2009 2:52:51 AM
Subject: Re: Maps getting stuck at 100%
Hi Himanshu,
The map progress percentage is calculated based on the input read, rather than
the processing actually done. So, if you're doing a lot of work in your mapper,
or reading ahead of what you've processed, you'll see this behavior reasonably
often. It also can show up sometimes in streaming jobs if you are doing a lot
of work per row, since have more buffering going on between the counters and
your actual mapper work.
The easiest way to see what the tasks are doing is to drill down to the logs
for an individual task that's stuck at 100%. If you add some logging output to
your program, that can be helpful. Another trick, if you have the right access,
is to ssh into your tasktracker node and send the SIGQUIT signal to one of your
task pids - this will make it dump stack to its stdout log, which you can then
inspect to understand what's going on.
Hope that helps
-Todd
On Mon, Nov 23, 2009 at 11:48 PM, himanshu chandola
<himanshu_cool...@yahoo.com> wrote:
Hi,
>>I use cloudera's distribution for hadoop. What I see is that a small fraction
>>of maps get stuck at 100%. They show up as 100% but continue running. After a
>>lot of delay, they succeed finally but it takes a while, like 10 mins from
>>the time when they show up as 100%.
>
>>We recently reformatted our hadoop fs. Could it be related to that ?
>
>
>>Thanks
>
>
>
>
>> Morpheus: Do you believe in fate, Neo?
>>Neo: No.
>>Morpheus: Why Not?
>>Neo: Because I don't like the idea that I'm not in control of my life.
>
>
>
>
>
