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 EEAB118DA4 for ; Wed, 28 Oct 2015 11:30:40 +0000 (UTC) Received: (qmail 42339 invoked by uid 500); 28 Oct 2015 11:30:27 -0000 Delivered-To: apmail-hadoop-common-issues-archive@hadoop.apache.org Received: (qmail 42284 invoked by uid 500); 28 Oct 2015 11:30:27 -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 42263 invoked by uid 99); 28 Oct 2015 11:30:27 -0000 Received: from arcas.apache.org (HELO arcas) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 28 Oct 2015 11:30:27 +0000 Received: from arcas.apache.org (localhost [127.0.0.1]) by arcas (Postfix) with ESMTP id B27932C1F56 for ; Wed, 28 Oct 2015 11:30:27 +0000 (UTC) Date: Wed, 28 Oct 2015 11:30:27 +0000 (UTC) From: "Kai Zheng (JIRA)" To: common-issues@hadoop.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Updated] (HADOOP-12047) Indicate preference not to affect input buffers during coding in erasure coder 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-12047?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Kai Zheng updated HADOOP-12047: ------------------------------- Attachment: HADOOP-12047-v2.patch Rebased the patch on trunk. Ready for review, thanks. This one is highly relied upon by other issues. > Indicate preference not to affect input buffers during coding in erasure coder > ------------------------------------------------------------------------------ > > Key: HADOOP-12047 > URL: https://issues.apache.org/jira/browse/HADOOP-12047 > Project: Hadoop Common > Issue Type: Sub-task > Reporter: Kai Zheng > Assignee: Kai Zheng > Fix For: HDFS-7285 > > Attachments: HADOOP-12047-HDFS-7285-v1.patch, HADOOP-12047-v2.patch, initial-poc.patch > > > It's good to define and ensure input buffers are not affected during coding process in raw erasure coders. Below are copied from discussion with [~jingzhao] in HDFS-8481: > bq. In that case we cannot reuse the source buffers I guess? Then do we need to expose this information in the decoder? > bq. Good catch Jing! Yes in this case we can't reuse the source buffers here as they need to be passed to caller/applications without being changed. I'm planning to re-implement the Java coders in HADOOP-12041 and related, when done it's possible to ensure the input buffers not to be affected. Benefits of doing this in coder layer: 1) a more clear contract between coder and caller in more general sense for the inputs; 2) concrete coder may have specific tweak to optimize in the aspect, ideally no input data copying at all, worst, make the copy, but all transparent to callers; 3) allow new coders (LRC, HH) to be layered on other primitive coders (RS, XOR) more easily. -- This message was sent by Atlassian JIRA (v6.3.4#6332)