Return-Path: X-Original-To: apmail-hadoop-hdfs-user-archive@minotaur.apache.org Delivered-To: apmail-hadoop-hdfs-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 6252410AB1 for ; Wed, 13 Nov 2013 14:23:36 +0000 (UTC) Received: (qmail 29824 invoked by uid 500); 13 Nov 2013 14:23:30 -0000 Delivered-To: apmail-hadoop-hdfs-user-archive@hadoop.apache.org Received: (qmail 29235 invoked by uid 500); 13 Nov 2013 14:23:26 -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 29228 invoked by uid 99); 13 Nov 2013 14:23:26 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 13 Nov 2013 14:23:26 +0000 X-ASF-Spam-Status: No, hits=2.2 required=5.0 tests=HTML_MESSAGE,RCVD_IN_DNSWL_NONE,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of john.lilley@redpoint.net designates 206.225.164.219 as permitted sender) Received: from [206.225.164.219] (HELO hub021-nj-4.exch021.serverdata.net) (206.225.164.219) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 13 Nov 2013 14:23:19 +0000 Received: from MBX021-E3-NJ-2.exch021.domain.local ([10.240.4.78]) by HUB021-NJ-4.exch021.domain.local ([10.240.4.39]) with mapi id 14.03.0158.001; Wed, 13 Nov 2013 06:22:58 -0800 From: John Lilley To: "user@hadoop.apache.org" Subject: FSDataInputStream: setReadAhead, setDropBehind Thread-Topic: FSDataInputStream: setReadAhead, setDropBehind Thread-Index: Ac7ge1hJ7FQB0lkDQaGq+e/itsrZzA== Date: Wed, 13 Nov 2013 14:22:58 +0000 Message-ID: <869970D71E26D7498BDAC4E1CA92226B86DBB1AA@MBX021-E3-NJ-2.exch021.domain.local> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [173.160.43.60] Content-Type: multipart/alternative; boundary="_000_869970D71E26D7498BDAC4E1CA92226B86DBB1AAMBX021E3NJ2exch_" MIME-Version: 1.0 X-Virus-Checked: Checked by ClamAV on apache.org --_000_869970D71E26D7498BDAC4E1CA92226B86DBB1AAMBX021E3NJ2exch_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I'm assuming that these methods exist to improve performance of certain I/O= patterns, but the API doc doesn't explain when one would use them. Our so= ftware's I/O pattern is mostly sequential I/O in large buffers (e.g. 256k).= Would one set these differently for local block I/O vs remote block I/O? Thanks John --_000_869970D71E26D7498BDAC4E1CA92226B86DBB1AAMBX021E3NJ2exch_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

I’m assuming that these methods exist to impro= ve performance of certain I/O patterns, but the API doc doesn’t expla= in when one would use them.  Our software’s I/O pattern is mostl= y sequential I/O in large buffers (e.g. 256k).  Would one set these differently for local block I/O vs remote block I/O?<= /p>

Thanks

John

 

 

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