From dev-return-60182-archive-asf-public=cust-asf.ponee.io@pig.apache.org Thu Jan 3 16:58:05 2019 Return-Path: X-Original-To: archive-asf-public@cust-asf.ponee.io Delivered-To: archive-asf-public@cust-asf.ponee.io Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by mx-eu-01.ponee.io (Postfix) with SMTP id 2096F18067A for ; Thu, 3 Jan 2019 16:58:04 +0100 (CET) Received: (qmail 76409 invoked by uid 500); 3 Jan 2019 15:58:03 -0000 Mailing-List: contact dev-help@pig.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@pig.apache.org Delivered-To: mailing list dev@pig.apache.org Received: (qmail 75978 invoked by uid 500); 3 Jan 2019 15:58:03 -0000 Delivered-To: apmail-hadoop-pig-dev@hadoop.apache.org Received: (qmail 75975 invoked by uid 99); 3 Jan 2019 15:58:03 -0000 Received: from pnap-us-west-generic-nat.apache.org (HELO spamd1-us-west.apache.org) (209.188.14.142) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 03 Jan 2019 15:58:03 +0000 Received: from localhost (localhost [127.0.0.1]) by spamd1-us-west.apache.org (ASF Mail Server at spamd1-us-west.apache.org) with ESMTP id 38115D0DBF for ; Thu, 3 Jan 2019 15:58:03 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at spamd1-us-west.apache.org X-Spam-Flag: NO X-Spam-Score: -109.501 X-Spam-Level: X-Spam-Status: No, score=-109.501 tagged_above=-999 required=6.31 tests=[ENV_AND_HDR_SPF_MATCH=-0.5, KAM_ASCII_DIVIDERS=0.8, RCVD_IN_DNSWL_MED=-2.3, SPF_PASS=-0.001, USER_IN_DEF_SPF_WL=-7.5, USER_IN_WHITELIST=-100] autolearn=disabled Received: from mx1-lw-us.apache.org ([10.40.0.8]) by localhost (spamd1-us-west.apache.org [10.40.0.7]) (amavisd-new, port 10024) with ESMTP id gKVx35fKyPK9 for ; Thu, 3 Jan 2019 15:58:02 +0000 (UTC) Received: from mailrelay1-us-west.apache.org (mailrelay1-us-west.apache.org [209.188.14.139]) by mx1-lw-us.apache.org (ASF Mail Server at mx1-lw-us.apache.org) with ESMTP id D0FE96110F for ; Thu, 3 Jan 2019 15:58:01 +0000 (UTC) Received: from jira-lw-us.apache.org (unknown [207.244.88.139]) by mailrelay1-us-west.apache.org (ASF Mail Server at mailrelay1-us-west.apache.org) with ESMTP id 553B4E2634 for ; Thu, 3 Jan 2019 15:58:01 +0000 (UTC) Received: from jira-lw-us.apache.org (localhost [127.0.0.1]) by jira-lw-us.apache.org (ASF Mail Server at jira-lw-us.apache.org) with ESMTP id B200425400 for ; Thu, 3 Jan 2019 15:58:00 +0000 (UTC) Date: Thu, 3 Jan 2019 15:58:00 +0000 (UTC) From: "Adam Szita (JIRA)" To: pig-dev@hadoop.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (PIG-5373) InterRecordReader might skip records if certain sync markers are used MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 [ https://issues.apache.org/jira/browse/PIG-5373?page=3Dcom.atlassian.j= ira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=3D167331= 71#comment-16733171 ]=20 Adam Szita commented on PIG-5373: --------------------------------- Committed to trunk, thanks a lot for reviewing Nandor! > InterRecordReader might skip records if certain sync markers are used > --------------------------------------------------------------------- > > Key: PIG-5373 > URL: https://issues.apache.org/jira/browse/PIG-5373 > Project: Pig > Issue Type: Bug > Reporter: Adam Szita > Assignee: Adam Szita > Priority: Major > Attachments: PIG-5373.0.patch, PIG-5373.1.patch > > > Due to bug in InterRecordReader#skipUntilMarkerOrSplitEndOrEOF(), it can = happen that sync markers are not identified while reading the interim binar= y file used to hold data between jobs. > In such files sync markers are placed upon writing, which later help duri= ng reading the data. These are random generated and it seems like that in s= ome rare combinations of markers and data preceding it, they=C2=A0cannot be= =C2=A0not found. This can result in reading through all the bytes (looking = for the marker) and reaching split end or EOF, and=C2=A0extracting no recor= ds at all. > This symptom is also=C2=A0observable from JobHistory stats, where if a jo= b is affected by this issue, will have tasks that have=C2=A0HDFS_BYTES_READ= or=C2=A0FILE_BYTES_READ about equal to the number bytes of the split, but = at the same time having=C2=A0MAP_INPUT_RECORDS=3D0 > One such (test) example is this: > {code:java} > marker: [-128, -128, 4] , data: [127, -1, 2, -128, -128, -128, 4, 1, 2, 3= ]{code} > Due to=C2=A0a bug, such markers=C2=A0whose prefix overlap with the last d= ata chunk are not seen by the reader. -- This message was sent by Atlassian JIRA (v7.6.3#76005)