From general-return-4093-apmail-hadoop-general-archive=hadoop.apache.org@hadoop.apache.org Mon Jul 25 22:28:58 2011 Return-Path: X-Original-To: apmail-hadoop-general-archive@minotaur.apache.org Delivered-To: apmail-hadoop-general-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 1547B6F38 for ; Mon, 25 Jul 2011 22:28:57 +0000 (UTC) Received: (qmail 26777 invoked by uid 500); 25 Jul 2011 22:28:56 -0000 Delivered-To: apmail-hadoop-general-archive@hadoop.apache.org Received: (qmail 26722 invoked by uid 500); 25 Jul 2011 22:28:55 -0000 Mailing-List: contact general-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: general@hadoop.apache.org Delivered-To: mailing list general@hadoop.apache.org Received: (qmail 26714 invoked by uid 99); 25 Jul 2011 22:28:55 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 25 Jul 2011 22:28:55 +0000 X-ASF-Spam-Status: No, hits=-0.7 required=5.0 tests=RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of eli@cloudera.com designates 209.85.210.176 as permitted sender) Received: from [209.85.210.176] (HELO mail-iy0-f176.google.com) (209.85.210.176) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 25 Jul 2011 22:28:48 +0000 Received: by iyi20 with SMTP id 20so7711229iyi.35 for ; Mon, 25 Jul 2011 15:28:27 -0700 (PDT) MIME-Version: 1.0 Received: by 10.231.5.217 with SMTP id 25mr3800201ibw.153.1311632906974; Mon, 25 Jul 2011 15:28:26 -0700 (PDT) Received: by 10.231.13.195 with HTTP; Mon, 25 Jul 2011 15:28:26 -0700 (PDT) In-Reply-To: <0BD2A055-A774-4C6C-8052-C71F7860FCAA@apache.org> References: <0BD2A055-A774-4C6C-8052-C71F7860FCAA@apache.org> Date: Mon, 25 Jul 2011 15:28:26 -0700 Message-ID: Subject: Re: MR1 next steps From: Eli Collins To: general@hadoop.apache.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Virus-Checked: Checked by ClamAV on apache.org On Mon, Jul 25, 2011 at 3:17 PM, Allen Wittenauer 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. =A0Note that the >> move to MR2 will affect some APIs (eg metrics, contrib projects that >> only work against MR1, etc). > > =A0 =A0 =A0 =A0Don'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 w= hile 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. > > =A0 =A0 =A0 =A0What are the three implementations? =A0I 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. Thanks, Eli