Return-Path: Delivered-To: apmail-hadoop-mapreduce-user-archive@minotaur.apache.org Received: (qmail 96224 invoked from network); 14 Mar 2010 11:34:08 -0000 Received: from unknown (HELO mail.apache.org) (140.211.11.3) by 140.211.11.9 with SMTP; 14 Mar 2010 11:34:08 -0000 Received: (qmail 4061 invoked by uid 500); 14 Mar 2010 11:33:25 -0000 Delivered-To: apmail-hadoop-mapreduce-user-archive@hadoop.apache.org Received: (qmail 3988 invoked by uid 500); 14 Mar 2010 11:33:24 -0000 Mailing-List: contact mapreduce-user-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: mapreduce-user@hadoop.apache.org Delivered-To: mailing list mapreduce-user@hadoop.apache.org Received: (qmail 3980 invoked by uid 99); 14 Mar 2010 11:33:24 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Sun, 14 Mar 2010 11:33:24 +0000 X-ASF-Spam-Status: No, hits=4.4 required=10.0 tests=FREEMAIL_ENVFROM_END_DIGIT,FREEMAIL_FROM,HTML_MESSAGE,RCVD_IN_DNSWL_NONE,SPF_PASS,T_TO_NO_BRKTS_FREEMAIL X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of psdc1978@gmail.com designates 72.14.220.158 as permitted sender) Received: from [72.14.220.158] (HELO fg-out-1718.google.com) (72.14.220.158) by apache.org (qpsmtpd/0.29) with ESMTP; Sun, 14 Mar 2010 11:33:16 +0000 Received: by fg-out-1718.google.com with SMTP id e12so800288fga.11 for ; Sun, 14 Mar 2010 04:32:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:date:message-id:subject :from:to:content-type; bh=f7aNWob3sa29sCxvtGpm7s3ZR8dnZ6wcEXB0QBla2NI=; b=i+DbnbLtzSBxcgGelugvMhPuvCLBSA0ybOpdixScYe1LYWgyiRzbQnC0qxJyIGS1oG zx+0LcLEkzXY3s0g/WOOn5mzTiCwac/MSoeCFLPy2KMr6KGA0mB8P/DxKlhsHGSjqnwm 8PhVyll5vvsqU5tR9TO+6SRUr9ys/kmzrMM64= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=ZN4s10OcAfoiqLyny50+r1h45J/ioSGb9y7V4YiSuNvY3NyEkIAFkeSYVv7ndXawRf q2d1iUd9sgLUvg325yaYR4nY0R9uKTPG/32xwLHsS16SOTTZ1Dvm1vBf/tZJApWihPGy MraT+fnRmim4MxmsrolzfosQJUYNVZ42Lpx88= MIME-Version: 1.0 Received: by 10.239.149.196 with SMTP id k4mr699779hbb.138.1268566376252; Sun, 14 Mar 2010 04:32:56 -0700 (PDT) Date: Sun, 14 Mar 2010 11:32:56 +0000 Message-ID: <61fec3fc1003140432ie412f9br2946bfd2b611ae7a@mail.gmail.com> Subject: What's the purpose of a setup and cleanup task? From: psdc1978 To: mapreduce-user@hadoop.apache.org Content-Type: multipart/alternative; boundary=001485f7d6243b06f50481c120fe X-Virus-Checked: Checked by ClamAV on apache.org --001485f7d6243b06f50481c120fe Content-Type: text/plain; charset=ISO-8859-1 Hi, I would like to understand what's the purpose of a setup and cleanup task. During the start-up of the job tracker, it will be assigned 2 setup tasks and 2 cleanup tasks for map and for the reduce. My questions are: - What's the purpose of a setup task? - The setup class runs on the jobtracker side or on the tasktracker side? - If I set around 50 map tasks to run in my hadoop example, will only one setup task initiate all map activities? (The same question for the reduce side) The above questions are also for the cleanup task. Regards, -- Pedro --001485f7d6243b06f50481c120fe Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi,

I would like to understand what's the purpose of a setup an= d cleanup task.

During the start-up of the job tracker, it will be a= ssigned 2 setup tasks and 2 cleanup tasks for map and for the reduce. My qu= estions are:
=A0
- What's the purpose of a setup task?
=A0
- = The setup class runs on the jobtracker side or on the tasktracker side?
=
- If I set around 50 map tasks to run in my hadoop example, will only o= ne setup task initiate all map activities? (The same question for the reduc= e side)


The above questions are also for the cleanup task.


Regar= ds,
--
Pedro
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