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Posted to common-user@hadoop.apache.org by hong <mi...@163.com> on 2008/06/03 17:31:47 UTC

how to execute two consecutive map-reduce pairs?

Hi all

A job must be done in two pairs of map reduce, That is, Map1==>  
reduce1 ==> map2==>reduce2. "==>" means the output file of left is  
the input of the right.
To do that job, can I just create only one JobConf instance, and  
invoke JobClient.runJob(conf) once?

Is there any similar example?

Thank you, in advance! 
   

Re: how to execute two consecutive map-reduce pairs?

Posted by Christophe Taton <ta...@apache.org>.
Maybe you can check org.apache.hadoop.mapred.jobcontrol.*
I did not try it myself but it looks like this is what you need.

Cheers,
Christophe

On Tue, Jun 3, 2008 at 5:55 PM, Ted Dunning <te...@gmail.com> wrote:

> No.
>
> At least you need to call runJob twice.  Typically, it is safer to create
> two job configurations so you don't forget to change something from the
> first jobs.
>
> It isn't a big deal.  Just do it!
>
> On Tue, Jun 3, 2008 at 8:31 AM, hong <mi...@163.com> wrote:
>
> > Hi all
> >
> > A job must be done in two pairs of map reduce, That is, Map1==> reduce1
> ==>
> > map2==>reduce2. "==>" means the output file of left is the input of the
> > right.
> > To do that job, can I just create only one JobConf instance, and invoke
> > JobClient.runJob(conf) once?
> >
> > Is there any similar example?
> >
> > Thank you, in advance!
>
>
>
>
> --
> ted
>

Re: how to execute two consecutive map-reduce pairs?

Posted by Ted Dunning <te...@gmail.com>.
No.

At least you need to call runJob twice.  Typically, it is safer to create
two job configurations so you don't forget to change something from the
first jobs.

It isn't a big deal.  Just do it!

On Tue, Jun 3, 2008 at 8:31 AM, hong <mi...@163.com> wrote:

> Hi all
>
> A job must be done in two pairs of map reduce, That is, Map1==> reduce1 ==>
> map2==>reduce2. "==>" means the output file of left is the input of the
> right.
> To do that job, can I just create only one JobConf instance, and invoke
> JobClient.runJob(conf) once?
>
> Is there any similar example?
>
> Thank you, in advance!




-- 
ted