Return-Path: X-Original-To: apmail-hadoop-mapreduce-user-archive@minotaur.apache.org Delivered-To: apmail-hadoop-mapreduce-user-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 663E0E582 for ; Wed, 23 Jan 2013 06:23:42 +0000 (UTC) Received: (qmail 78991 invoked by uid 500); 23 Jan 2013 06:23:37 -0000 Delivered-To: apmail-hadoop-mapreduce-user-archive@hadoop.apache.org Received: (qmail 78897 invoked by uid 500); 23 Jan 2013 06:23:37 -0000 Mailing-List: contact user-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@hadoop.apache.org Delivered-To: mailing list user@hadoop.apache.org Received: (qmail 78890 invoked by uid 99); 23 Jan 2013 06:23:37 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 23 Jan 2013 06:23:37 +0000 X-ASF-Spam-Status: No, hits=-0.0 required=5.0 tests=SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of Ajay.Srivastava@guavus.com designates 204.232.241.167 as permitted sender) Received: from [204.232.241.167] (HELO mx1.guavus.com) (204.232.241.167) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 23 Jan 2013 06:23:29 +0000 Received: from mx1.guavus.com ([204.232.241.167]) by mx1.guavus.com ([204.232.241.167]) with mapi id 14.01.0379.000; Tue, 22 Jan 2013 22:23:08 -0800 From: Ajay Srivastava To: "user@hadoop.apache.org" Subject: io.sort.factor Thread-Topic: io.sort.factor Thread-Index: AQHN+TIb8c7jDiNvlEmtzYgPgs7jhQ== Date: Wed, 23 Jan 2013 06:23:07 +0000 Message-ID: <37B3024A-D884-4BD4-BBF5-D9C54BBB22F6@guavus.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [61.12.3.122] Content-Type: text/plain; charset="us-ascii" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Virus-Checked: Checked by ClamAV on apache.org Hi, io.sort.factor -- The number of streams to merge at once while sorting fi= les. This determines the number of open file handles. How can I use this parameter to improve performance of mapreduce job? My understanding from above description was If there are many spill records= then increasing io.sort.mb as well as io.sort.factor will help in better p= erformance. Increasing io.sort.mb helped but changing io.sort.factor (> 10)= does not seem to improve/degrade performance of mapred job. Regards, Ajay Srivastava=