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From Eli Collins <...@cloudera.com>
Subject Re: MR1 next steps
Date Mon, 25 Jul 2011 22:28:26 GMT
On Mon, Jul 25, 2011 at 3:17 PM, Allen Wittenauer <aw@apache.org> wrote:
> On Jul 25, 2011, at 11:59 AM, Eli Collins wrote:
>> Note! MR2 supports the current job
>> API - users don't need to rewrite their jobs to run on MR2 - this is
>> about the MR *implementation* not job compatibility.  Note that the
>> move to MR2 will affect some APIs (eg metrics, contrib projects that
>> only work against MR1, etc).
>        Don't forget that this completely breaks operations, as in our entire world
is about to get blown apart and it will take us quite a while to recover.

Yes, moving operations from MR1 to MR2 will require some work.

>> The current MR1 implementation will of
>> course remain supported in the current stable releases.
>> Rationale: there's a lot of cost but little gain to maintaining three
>> MR implementations.
>        What are the three implementations?  I only see two?

1. MR1 in stable
2. MR1 in trunk
3. MR2 in trunk

Given that we only recommend #1 and #3 it doesn't make sense to support #2.


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