hadoop-mapreduce-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Roth Effy <effyr...@gmail.com>
Subject Re: How can I record some position of context in Reduce()?
Date Wed, 13 Mar 2013 15:05:46 GMT
I want a n:n join as Cartesian product,but the DataJoinReducerBase looks
like only support equal join.
I want a non-equal join,but I have no idea now.


2013/3/13 Azuryy Yu <azuryyyu@gmail.com>

> you want a n:n join or 1:n join?
> On Mar 13, 2013 10:51 AM, "Roth Effy" <effyroth@gmail.com> wrote:
>
>> I want to join two table data in reducer.So I need to find the start of
>> the table.
>> someone said the DataJoinReducerBase can help me,isn't it?
>>
>>
>> 2013/3/13 Azuryy Yu <azuryyyu@gmail.com>
>>
>>> you cannot use RecordReader in Reducer.
>>>
>>> what's the mean of you want get the record position? I cannot
>>> understand, can you give a simple example?
>>>
>>>
>>> On Wed, Mar 13, 2013 at 9:56 AM, Roth Effy <effyroth@gmail.com> wrote:
>>>
>>>> sorry´╝îI still can't understand how to use recordreader in the
>>>> reduce(),because the input is a RawKeyValueIterator in the class
>>>> reducecontext.so,I'm confused.
>>>> anyway,thank you.
>>>>
>>>>
>>>> 2013/3/12 samir das mohapatra <samir.helpdoc@gmail.com>
>>>>
>>>>> Through the RecordReader and FileStatus you can get it.
>>>>>
>>>>>
>>>>> On Tue, Mar 12, 2013 at 4:08 PM, Roth Effy <effyroth@gmail.com>
wrote:
>>>>>
>>>>>> Hi,everyone,
>>>>>> I want to join the k-v pairs in Reduce(),but how to get the record
>>>>>> position?
>>>>>> Now,what I thought is to save the context status,but class Context
>>>>>> doesn't implement a clone construct method.
>>>>>>
>>>>>> Any help will be appreciated.
>>>>>> Thank you very much.
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>

Mime
View raw message