Yes, if ur block size is 64mb. Btw, block size is configurable in Hadoop.
Best Regards,
Anil
On Feb 1, 2012, at 5:06 PM, Mark Kerzner <mark.kerz...@shmsoft.com> wrote:
> Anil,
>
> do you mean one block of HDFS, like 64MB?
>
> Mark
>
> On Wed, Feb 1, 2012 at 7:03 PM, Anil Gupta <anilgupt...@gmail.com> wrote:
>
>> Do u have enough data to start more than one mapper?
>> If entire data is less than a block size then only 1 mapper will run.
>>
>> Best Regards,
>> Anil
>>
>> On Feb 1, 2012, at 4:21 PM, Mark Kerzner <mark.kerz...@shmsoft.com> wrote:
>>
>>> Hi,
>>>
>>> I have a simple MR job, and I want each Mapper to get one line from my
>>> input file (which contains further instructions for lengthy processing).
>>> Each line is 100 characters long, and I tell Hadoop to read only 100
>> bytes,
>>>
>>>
>> job.getConfiguration().setInt("mapreduce.input.linerecordreader.line.maxlength",
>>> 100);
>>>
>>> I see that this part works - it reads only one line at a time, and if I
>>> change this parameter, it listens.
>>>
>>> However, on a cluster only one node receives all the map tasks. Only one
>>> map tasks is started. The others never get anything, they just wait. I've
>>> added 100 seconds wait to the mapper - no change!
>>>
>>> Any advice?
>>>
>>> Thank you. Sincerely,
>>> Mark
>>
