Hello,

I am trying to write a program where I need to write multiple rounds of map
and reduce.

The output of the last round of map-reduce must be fed into the input of the
next round.

Can anyone please guide me to any link / material that can teach me as to
how I can achieve this.

Thanks a lot in advance!

Thanks & regards
Arko

Hi,

On Mon, Jun 13, 2011 at 11:46 PM, Arko Provo Mukherjee
<[EMAIL PROTECTED]> wrote:
> Hello,
>
> I am trying to write a program where I need to write multiple rounds of map
> and reduce.
>
> The output of the last round of map-reduce must be fed into the input of the
> next round.
>
> Can anyone please guide me to any link / material that can teach me as to
> how I can achieve this.
>

The way I do it is:

create job1
job1 <-- feed all the configuration parameters (incl input and output
path) to this job
run job 1

create job2
job2 <-- feed all config params (output of job1 as input, another path
as output)
run job2

....
so on.

I think this is the recommended way of running multiple rounds of MR in hadoop.

-b

Well, you can define a job for each round and then, you can define the
running workflow based in your implementation and to chain your jobs

El 6/13/2011 5:46 PM, Arko Provo Mukherjee escribi�:
> Hello,
>
> I am trying to write a program where I need to write multiple rounds
> of map and reduce.
>
> The output of the last round of map-reduce must be fed into the input
> of the next round.
>
> Can anyone please guide me to any link / material that can teach me as
> to how I can achieve this.
>
> Thanks a lot in advance!
>
> Thanks & regards
> Arko

--
Marcos Lu�s Ort�z Valmaseda
  Software Engineer (UCI)
  http://marcosluis2186.posterous.com
  http://twitter.com/marcosluis2186

If you know for certain that it needs to be split into multiple work units I would suggest looking into Oozie. Easy to install, light weight, low learning curve... for my purposes it's been very helpful so far. I am also fairly certain you can chain multiple job confs into the same run but I have not actually tried that therefore I can't promise it is easy or possible.

http://www.cloudera.com/blog/2010/07/whats-new-in-cdh3-b2-oozie/

If you are not running CDH3u0 then you can also get the tarball and documentation directly here:
https://ccp.cloudera.com/display/SUPPORT/CDH3+Downloadable+Tarballs

Matt

-----Original Message-----
From: Marcos Ortiz [mailto:[EMAIL PROTECTED]]
Sent: Monday, June 13, 2011 4:57 PM
To: [EMAIL PROTECTED]
Cc: Arko Provo Mukherjee
Subject: Re: Programming Multiple rounds of mapreduce

Well, you can define a job for each round and then, you can define the
running workflow based in your implementation and to chain your jobs

El 6/13/2011 5:46 PM, Arko Provo Mukherjee escribió:
> Hello,
>
> I am trying to write a program where I need to write multiple rounds
> of map and reduce.
>
> The output of the last round of map-reduce must be fed into the input
> of the next round.
>
> Can anyone please guide me to any link / material that can teach me as
> to how I can achieve this.
>
> Thanks a lot in advance!
>
> Thanks & regards
> Arko

--
Marcos Luís Ortíz Valmaseda
  Software Engineer (UCI)
  http://marcosluis2186.posterous.com
  http://twitter.com/marcosluis2186
  

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Thanks Matt,

Arko, if you plan to use Oozie, you can have a simple coordinator job that
does does, for example (the following schedules a WF every 5 mins that
consumes the output produced by the previous run, you just have to have the
initial data)

Thxs.

Alejandro

----
<coordinator-app name="coord-1" frequency="${coord:minutes(5)}"
start="${start}" end="${end}" timezone="UTC"
                 xmlns="uri:oozie:coordinator:0.1">
  <controls>
    <concurrency>1</concurrency>
  </controls>

  <datasets>
    <dataset name="data" frequency="${coord:minutes(5)}"
initial-instance="${start}" timezone="UTC">

<uri-template>${nameNode}/user/${coord:user()}/examples/${dataRoot}/${YEAR}-${MONTH}-${DAY}-${HOUR}-${MINUTE}
      </uri-template>
    </dataset>
  </datasets>

  <input-events>
    <data-in name="input" dataset="data">
      <instance>${coord:current(0)}</instance>
    </data-in>
  </input-events>

  <output-events>
    <data-out name="output" dataset="data">
      <instance>${coord:current(1)}</instance>
    </data-out>
  </output-events>

  <action>
    <workflow>

<app-path>${nameNode}/user/${coord:user()}/examples/apps/subwf-1</app-path>
      <configuration>
        <property>
          <name>jobTracker</name>
          <value>${jobTracker}</value>
        </property>
        <property>
          <name>nameNode</name>
          <value>${nameNode}</value>
        </property>
        <property>
          <name>queueName</name>
          <value>${queueName}</value>
        </property>
        <property>
          <name>examplesRoot</name>
          <value>${examplesRoot}</value>
        </property>
        <property>
          <name>inputDir</name>
          <value>${coord:dataIn('input')}</value>
        </property>
        <property>
          <name>outputDir</name>
          <value>${coord:dataOut('output')}</value>
        </property>
      </configuration>
    </workflow>
  </action>
</coordinator-app>
------

On Mon, Jun 13, 2011 at 3:01 PM, GOEKE, MATTHEW (AG/1000) <
[EMAIL PROTECTED]> wrote:

> If you know for certain that it needs to be split into multiple work units
> I would suggest looking into Oozie. Easy to install, light weight, low
> learning curve... for my purposes it's been very helpful so far. I am also
> fairly certain you can chain multiple job confs into the same run but I have
> not actually tried that therefore I can't promise it is easy or possible.
>
> http://www.cloudera.com/blog/2010/07/whats-new-in-cdh3-b2-oozie/
>
> If you are not running CDH3u0 then you can also get the tarball and
> documentation directly here:
> https://ccp.cloudera.com/display/SUPPORT/CDH3+Downloadable+Tarballs
>
> Matt
>
> -----Original Message-----
> From: Marcos Ortiz [mailto:[EMAIL PROTECTED]]
> Sent: Monday, June 13, 2011 4:57 PM
> To: [EMAIL PROTECTED]
> Cc: Arko Provo Mukherjee
> Subject: Re: Programming Multiple rounds of mapreduce
>
> Well, you can define a job for each round and then, you can define the
> running workflow based in your implementation and to chain your jobs
>
> El 6/13/2011 5:46 PM, Arko Provo Mukherjee escribió:
> > Hello,
> >
> > I am trying to write a program where I need to write multiple rounds
> > of map and reduce.
> >
> > The output of the last round of map-reduce must be fed into the input
> > of the next round.
> >
> > Can anyone please guide me to any link / material that can teach me as
> > to how I can achieve this.
> >
> > Thanks a lot in advance!
> >
> > Thanks & regards
> > Arko
>
> --
> Marcos Luís Ortíz Valmaseda
>  Software Engineer (UCI)
>  http://marcosluis2186.posterous.com
>  http://twitter.com/marcosluis2186
>
>
> This e-mail message may contain privileged and/or confidential information,
> and is intended to be received only by persons entitled
> to receive such information. If you have received this e-mail in error,
> please notify the sender immediately. Please delete it and
> all attachments from any servers, hard drives or any other media. Other use

I think HaLoop is a framework which can answer your question:
http://code.google.com/p/haloop/

On Mon, Jun 13, 2011 at 5:46 PM, Arko Provo Mukherjee <
[EMAIL PROTECTED]> wrote:

> Hello,
>
> I am trying to write a program where I need to write multiple rounds of map
> and reduce.
>
> The output of the last round of map-reduce must be fed into the input of
> the next round.
>
> Can anyone please guide me to any link / material that can teach me as to
> how I can achieve this.
>
> Thanks a lot in advance!
>
> Thanks & regards
> Arko
>

--
Best Regards,
Mostafa Ead

Hello,

Thanks everyone for your responses.

I am new to Hadoop, so this was a lot of new information for me. I will
surely go though all of these.

However, I was actually hoping that someone could point me to some example
codes where multiple rounds of map-reduce has been used.

Please let me know if anyone has any such examples as they are the best way
to learn for me :-)

Thanks much!
Cheers
Arko

On Mon, Jun 13, 2011 at 5:30 PM, Moustafa Gaber <[EMAIL PROTECTED]>wrote:

> I think HaLoop is a framework which can answer your question:
> http://code.google.com/p/haloop/
>
>
> On Mon, Jun 13, 2011 at 5:46 PM, Arko Provo Mukherjee <
> [EMAIL PROTECTED]> wrote:
>
>> Hello,
>>
>> I am trying to write a program where I need to write multiple rounds of
>> map and reduce.
>>
>> The output of the last round of map-reduce must be fed into the input of
>> the next round.
>>
>> Can anyone please guide me to any link / material that can teach me as to
>> how I can achieve this.
>>
>> Thanks a lot in advance!
>>
>> Thanks & regards
>> Arko
>>
>
>
>
> --
> Best Regards,
> Mostafa Ead
>
>

Actually, HaLoop is a new framework above Hadoop which targets the problem
of transitive closure algorithms. This type of algorithms contain rounds of
hadoop jobs, so I think it may contain some useful examples for you.

On Mon, Jun 13, 2011 at 6:39 PM, Arko Provo Mukherjee <
[EMAIL PROTECTED]> wrote:

> Hello,
>
> Thanks everyone for your responses.
>
> I am new to Hadoop, so this was a lot of new information for me. I will
> surely go though all of these.
>
> However, I was actually hoping that someone could point me to some example
> codes where multiple rounds of map-reduce has been used.
>
> Please let me know if anyone has any such examples as they are the best way
> to learn for me :-)
>
> Thanks much!
> Cheers
> Arko
>
>
>
>
> On Mon, Jun 13, 2011 at 5:30 PM, Moustafa Gaber <[EMAIL PROTECTED]>wrote:
>
>> I think HaLoop is a framework which can answer your question:
>> http://code.google.com/p/haloop/
>>
>>
>> On Mon, Jun 13, 2011 at 5:46 PM, Arko Provo Mukherjee <
>> [EMAIL PROTECTED]> wrote:
>>
>>> Hello,
>>>
>>> I am trying to write a program where I need to write multiple rounds of
>>> map and reduce.
>>>
>>> The output of the last round of map-reduce must be fed into the input of
>>> the next round.
>>>
>>> Can anyone please guide me to any link / material that can teach me as to
>>> how I can achieve this.
>>>
>>> Thanks a lot in advance!
>>>
>>> Thanks & regards
>>> Arko
>>>
>>
>>
>>
>> --
>> Best Regards,
>> Mostafa Ead
>>
>>
>
--
Best Regards,
Mostafa Ead

You could have a look at the MapReduce pipelines in Apache Mahout
(http://mahout.apache.org). See for instance
org.apache.mahout.cf.taste.hadoop.item.RecommenderJob. This shows how
most of Mahout constructs and runs a series of rounds of MapReduce to
accomplish a task. Each job feeds into one or more of the later
rounds. It is at least an example of getting in done in straight
Hadoop -- though workflow systems like Oozie et al are probably the
kinds of things you want to look at now.

On Mon, Jun 13, 2011 at 10:46 PM, Arko Provo Mukherjee
<[EMAIL PROTECTED]> wrote:
> Hello,
>
> I am trying to write a program where I need to write multiple rounds of map
> and reduce.
>
> The output of the last round of map-reduce must be fed into the input of the
> next round.
>
> Can anyone please guide me to any link / material that can teach me as to
> how I can achieve this.
>
> Thanks a lot in advance!
>
> Thanks & regards
> Arko
>