Return-Path: X-Original-To: apmail-hadoop-common-issues-archive@minotaur.apache.org Delivered-To: apmail-hadoop-common-issues-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id BD07318FF8 for ; Thu, 15 Oct 2015 09:20:06 +0000 (UTC) Received: (qmail 8221 invoked by uid 500); 15 Oct 2015 09:20:05 -0000 Delivered-To: apmail-hadoop-common-issues-archive@hadoop.apache.org Received: (qmail 7874 invoked by uid 500); 15 Oct 2015 09:20:05 -0000 Mailing-List: contact common-issues-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: common-issues@hadoop.apache.org Delivered-To: mailing list common-issues@hadoop.apache.org Received: (qmail 7594 invoked by uid 99); 15 Oct 2015 09:20:05 -0000 Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 15 Oct 2015 09:20:05 +0000 Date: Thu, 15 Oct 2015 09:20:05 +0000 (UTC) From: "Rajesh Balamohan (JIRA)" To: common-issues@hadoop.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (HADOOP-12444) Consider implementing lazy seek in S3AInputStream MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 [ https://issues.apache.org/jira/browse/HADOOP-12444?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14958563#comment-14958563 ] Rajesh Balamohan commented on HADOOP-12444: ------------------------------------------- Sure, whenever you have time. Thanks a lot [~thodemoor]. > Consider implementing lazy seek in S3AInputStream > ------------------------------------------------- > > Key: HADOOP-12444 > URL: https://issues.apache.org/jira/browse/HADOOP-12444 > Project: Hadoop Common > Issue Type: Sub-task > Components: fs/s3 > Affects Versions: 2.7.1 > Reporter: Rajesh Balamohan > Assignee: Rajesh Balamohan > Attachments: HADOOP-12444.1.patch, HADOOP-12444.WIP.patch > > > - Currently, "read(long position, byte[] buffer, int offset, int length)" is not implemented in S3AInputStream (unlike DFSInputStream). So, "readFully(long position, byte[] buffer, int offset, int length)" in S3AInputStream goes through the default implementation of seek(), read(), seek() in FSInputStream. > - However, seek() in S3AInputStream involves re-opening of connection to S3 everytime (https://github.com/apache/hadoop/blob/trunk/hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3AInputStream.java#L115). > - It would be good to consider having a lazy seek implementation to reduce connection overheads to S3. (e.g Presto implements lazy seek. https://github.com/facebook/presto/blob/master/presto-hive/src/main/java/com/facebook/presto/hive/PrestoS3FileSystem.java#L623) -- This message was sent by Atlassian JIRA (v6.3.4#6332)