Return-Path: 
 <issues-return-176666-apmail-hbase-issues-archive=hbase.apache.org@hbase.apache.org>
X-Original-To: apmail-hbase-issues-archive@www.apache.org
Delivered-To: apmail-hbase-issues-archive@www.apache.org
Received: from mail.apache.org (hermes.apache.org [140.211.11.3])
	by minotaur.apache.org (Postfix) with SMTP id CADCA10DE4
	for <apmail-hbase-issues-archive@www.apache.org>;
 Tue, 30 Dec 2014 04:37:13 +0000 (UTC)
Received: (qmail 3603 invoked by uid 500); 30 Dec 2014 04:37:14 -0000
Delivered-To: apmail-hbase-issues-archive@hbase.apache.org
Received: (qmail 3550 invoked by uid 500); 30 Dec 2014 04:37:14 -0000
Mailing-List: contact issues-help@hbase.apache.org; run by ezmlm
Precedence: bulk
List-Help: <mailto:issues-help@hbase.apache.org>
List-Unsubscribe: <mailto:issues-unsubscribe@hbase.apache.org>
List-Post: <mailto:issues@hbase.apache.org>
List-Id: <issues.hbase.apache.org>
Delivered-To: mailing list issues@hbase.apache.org
Received: (qmail 3538 invoked by uid 99); 30 Dec 2014 04:37:14 -0000
Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28)
    by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 30 Dec 2014 04:37:14 +0000
Date: Tue, 30 Dec 2014 04:37:13 +0000 (UTC)
From: "Liang Xie (JIRA)" <jira@apache.org>
To: issues@hbase.apache.org
Message-ID: <JIRA.12763969.1419831479000.113246.1419914233949@Atlassian.JIRA>
In-Reply-To: <JIRA.12763969.1419831479000@Atlassian.JIRA>
References: <JIRA.12763969.1419831479000@Atlassian.JIRA>
 <JIRA.12763969.1419831479485@arcas>
Subject: [jira] [Updated] (HBASE-12767) Fix a StoreFileScanner NPE in
 reverse scan flow
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/HBASE-12767?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Liang Xie updated HBASE-12767:
------------------------------
    Hadoop Flags: Reviewed

> Fix a StoreFileScanner NPE in reverse scan flow
> -----------------------------------------------
>
>                 Key: HBASE-12767
>                 URL: https://issues.apache.org/jira/browse/HBASE-12767
>             Project: HBase
>          Issue Type: Bug
>          Components: regionserver, Scanners
>    Affects Versions: 1.0.0, 2.0.0, 0.98.9
>            Reporter: Liang Xie
>            Assignee: Liang Xie
>             Fix For: 1.0.0, 2.0.0, 0.98.10, 1.1.0
>
>         Attachments: HBASE-12767.txt
>
>
> we observed a NPE in our internal 0.94 branch prd env:
> ERROR org.apache.hadoop.hbase.regionserver.HRegionServer: Failed openScanner
> java.lang.NullPointerException
> at org.apache.hadoop.hbase.regionserver.StoreFileScanner.seekToPreviousRow(StoreFileScanner.java:409)
> at org.apache.hadoop.hbase.regionserver.StoreFileScanner.backwardSeek(StoreFileScanner.java:467)
> at org.apache.hadoop.hbase.regionserver.ReversedStoreScanner.seekScanners(ReversedStoreScanner.java:78)
> at org.apache.hadoop.hbase.regionserver.StoreScanner.<init>(StoreScanner.java:154)
> at org.apache.hadoop.hbase.regionserver.ReversedStoreScanner.<init>(ReversedStoreScanner.java:49)
> at org.apache.hadoop.hbase.regionserver.Store.getScanner(Store.java:2216)
> at org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.<init>(HRegion.java:3984)
> at org.apache.hadoop.hbase.regionserver.ReversedRegionScannerImpl.<init>(ReversedRegionScannerImpl.java:43)
> at org.apache.hadoop.hbase.regionserver.HRegion.instantiateRegionScanner(HRegion.java:1851)
> at org.apache.hadoop.hbase.regionserver.HRegion.getScanner(HRegion.java:1837)
> at org.apache.hadoop.hbase.regionserver.HRegion.getScanner(HRegion.java:1812)
> at org.apache.hadoop.hbase.regionserver.HRegionServer.internalOpenScanner(HRegionServer.java:2752)
> at org.apache.hadoop.hbase.regionserver.HRegionServer.openScanner(HRegionServer.java:2715)
> After tracing, it turned out a boundary bug at HalfStoreFileReader. If we have a reverse scan request at "bottom" part, once the start row >= the last row at bottom part, the NPE will be encourtered, since we will invoke "next()", and "atEnd = true" will be called in HalfStoreFileReader, then when we want to do "seekBefore" or other sth in StoreFileScanner,  StoreFileScanner.cur will call:
> {code}
>       public Cell getKeyValue() {
>         if (atEnd) return null;
> {code}
> The fix is simple, we need to reset the "atEnd" flag once seekBefore op is successful. You can undo my HalfStoreFileReader change and run the new added case to see NPE.
> ps: I also found some cases in TestHRegion missing the "@Test" annotation, so fix them in the same patch as well.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)