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Posted to common-issues@hadoop.apache.org by "Hadoop QA (JIRA)" <ji...@apache.org> on 2010/07/16 00:00:55 UTC

[jira] Commented: (HADOOP-6834) TFile.append compares initial key against null lastKey

    [ https://issues.apache.org/jira/browse/HADOOP-6834?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12888939#action_12888939 ] 

Hadoop QA commented on HADOOP-6834:
-----------------------------------

-1 overall.  Here are the results of testing the latest attachment 
  http://issues.apache.org/jira/secure/attachment/12449597/hadoop-6834-20100715.patch
  against trunk revision 964134.

    +1 @author.  The patch does not contain any @author tags.

    +1 tests included.  The patch appears to include 2 new or modified tests.

    -1 javadoc.  The javadoc tool appears to have generated 1 warning messages.

    +1 javac.  The applied patch does not increase the total number of javac compiler warnings.

    +1 findbugs.  The patch does not introduce any new Findbugs warnings.

    +1 release audit.  The applied patch does not increase the total number of release audit warnings.

    +1 core tests.  The patch passed core unit tests.

    +1 contrib tests.  The patch passed contrib unit tests.

Test results: http://hudson.zones.apache.org/hudson/job/Hadoop-Patch-h4.grid.sp2.yahoo.net/617/testReport/
Findbugs warnings: http://hudson.zones.apache.org/hudson/job/Hadoop-Patch-h4.grid.sp2.yahoo.net/617/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html
Checkstyle results: http://hudson.zones.apache.org/hudson/job/Hadoop-Patch-h4.grid.sp2.yahoo.net/617/artifact/trunk/build/test/checkstyle-errors.html
Console output: http://hudson.zones.apache.org/hudson/job/Hadoop-Patch-h4.grid.sp2.yahoo.net/617/console

This message is automatically generated.

> TFile.append compares initial key against null lastKey  
> --------------------------------------------------------
>
>                 Key: HADOOP-6834
>                 URL: https://issues.apache.org/jira/browse/HADOOP-6834
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: io
>    Affects Versions: 0.20.1, 0.20.2
>            Reporter: Ahad Rana
>            Assignee: Hong Tang
>         Attachments: hadoop-6834-20100715.patch
>
>
> The following code in TFile.KeyReigster.close: 
>             byte[] lastKey = lastKeyBufferOS.getBuffer();
>             int lastLen = lastKeyBufferOS.size();
>             if (tfileMeta.getComparator().compare(key, 0, len, lastKey, 0,
>                 lastLen) < 0) {
>               throw new IOException("Keys are not added in sorted order");
>             }
> compares the initial  key (passed in via  TFile.Writer.append) against a technically NULL lastKey. lastKey is not initialized until after the first call to TFile.Writer.append. The underlying RawComparator interface used for comparisons does not stipulate the proper behavior when either length 1  or length 2 is zero. In the case of LongWritable, its WritableComparator implementation does an unsafe read on the passed in byte arrays b1 and b2. Since TFile pre-allocates the buffer used for storing lastKey, this passes a valid buffer with zero count to LongWritable's comparator, which ignores length and thus produces incorrect results. 

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