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MapReduce, mail # user - what's the default reducer number?


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Re: what's the default reducer number?
Jagat Singh 2012-09-11, 11:47
Just to add the name is depreciated in new Hadoop
Try to find
mapreduce.job.reduces

On Tue, Sep 11, 2012 at 9:43 PM, Bejoy Ks <[EMAIL PROTECTED]> wrote:

> Hi Lin
>
> The default values for all the properties are in
> core-default.xml
> hdfs-default.xml and
> mapred-default.xml
>
>
> Regards
> Bejoy KS
>
>
> On Tue, Sep 11, 2012 at 5:06 PM, Jason Yang <[EMAIL PROTECTED]>wrote:
>
>> Hi, Bejoy
>>
>> Thanks for you reply.
>>
>> where could I find the default value of mapred.reduce.tasks ? I have
>> checked the core-site.xml, hdfs-site.xml and mapred-site.xml, but I haven't
>> found it.
>>
>>
>> 2012/9/11 Bejoy Ks <[EMAIL PROTECTED]>
>>
>>> Hi Lin
>>>
>>> The default value for number of reducers is 1
>>>
>>> <name>mapred.reduce.tasks</name>
>>>   <value>1</value>
>>>
>>> It is not determined by data volume. You need to specify the number of
>>> reducers for your mapreduce jobs as per your data volume.
>>>
>>> Regards
>>> Bejoy KS
>>>
>>> On Tue, Sep 11, 2012 at 4:53 PM, Jason Yang <[EMAIL PROTECTED]>wrote:
>>>
>>>> Hi, all
>>>>
>>>> I was wondering what's the default number of reducer if I don't set it
>>>> in configuration?
>>>>
>>>> Will it change dynamically according to the output volume of Mapper?
>>>>
>>>> --
>>>> YANG, Lin
>>>>
>>>>
>>>
>>
>>
>> --
>> YANG, Lin
>>
>>
>