Return-Path: X-Original-To: apmail-hadoop-hdfs-issues-archive@minotaur.apache.org Delivered-To: apmail-hadoop-hdfs-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 2934010A07 for ; Thu, 18 Dec 2014 22:58:18 +0000 (UTC) Received: (qmail 69194 invoked by uid 500); 18 Dec 2014 22:58:18 -0000 Delivered-To: apmail-hadoop-hdfs-issues-archive@hadoop.apache.org Received: (qmail 69132 invoked by uid 500); 18 Dec 2014 22:58:17 -0000 Mailing-List: contact hdfs-issues-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: hdfs-issues@hadoop.apache.org Delivered-To: mailing list hdfs-issues@hadoop.apache.org Received: (qmail 69120 invoked by uid 99); 18 Dec 2014 22:58:17 -0000 Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 18 Dec 2014 22:58:17 +0000 Date: Thu, 18 Dec 2014 22:58:17 +0000 (UTC) From: "Konstantin Boudnik (JIRA)" To: hdfs-issues@hadoop.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (HDFS-3107) HDFS truncate 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/HDFS-3107?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14252476#comment-14252476 ] Konstantin Boudnik commented on HDFS-3107: ------------------------------------------ The diff between the two seems to be quite small, yet I guess it requires a formal review again. Hence +1 again. > HDFS truncate > ------------- > > Key: HDFS-3107 > URL: https://issues.apache.org/jira/browse/HDFS-3107 > Project: Hadoop HDFS > Issue Type: New Feature > Components: datanode, namenode > Reporter: Lei Chang > Assignee: Plamen Jeliazkov > Attachments: HDFS-3107-HDFS-7056-combined.patch, HDFS-3107.008.patch, HDFS-3107.patch, HDFS-3107.patch, HDFS-3107.patch, HDFS-3107.patch, HDFS-3107.patch, HDFS-3107.patch, HDFS-3107.patch, HDFS-3107.patch, HDFS-3107.patch, HDFS-3107.patch, HDFS-3107.patch, HDFS_truncate.pdf, HDFS_truncate.pdf, HDFS_truncate.pdf, HDFS_truncate_semantics_Mar15.pdf, HDFS_truncate_semantics_Mar21.pdf, editsStored, editsStored.xml > > Original Estimate: 1,344h > Remaining Estimate: 1,344h > > Systems with transaction support often need to undo changes made to the underlying storage when a transaction is aborted. Currently HDFS does not support truncate (a standard Posix operation) which is a reverse operation of append, which makes upper layer applications use ugly workarounds (such as keeping track of the discarded byte range per file in a separate metadata store, and periodically running a vacuum process to rewrite compacted files) to overcome this limitation of HDFS. -- This message was sent by Atlassian JIRA (v6.3.4#6332)