[
https://issues.apache.org/jira/browse/HDFS-1907?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13043103#comment-13043103
]
Daryn Sharp commented on HDFS-1907:
-----------------------------------
I just did a cursory read of {{getFinalizedBlockRange}}. If the file is
committed, it appears to throw an exception if the client attempts to read past
the end of file. However, in the case where the file has an uncompleted block,
I think there's a secondary bug where no exception is thrown if the client is
attempting to read past the end of the uncompleted block. Basically a final
bounds check should be added.
Small issue with the test. I know you probably copied-n-pasted, however
{{assertTrue(stat == 0)}} is an anti-pattern. {{assertTrue}} should used to
test a real boolean value, not a fabricated boolean within the assert. This
condition needs to be {{assertEquals(0, stat)}}. The reason is if
{{assertTrue}} fails, junit can't report the bad value. Whereas
{{assertEquals}} will report "I expected *this*, but got *that*".
If you feel esp. industrious, you might pay it forward and use a regexp to
search and replace the other similar conditions to {{assertEquals}}... The
next dev that breaks a test will thank you. How much you do is up to you, but
at least fix the new test.
> BlockMissingException upon concurrent read and write: reader was doing file
> position read while writer is doing write without hflush
> ------------------------------------------------------------------------------------------------------------------------------------
>
> Key: HDFS-1907
> URL: https://issues.apache.org/jira/browse/HDFS-1907
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: hdfs client
> Affects Versions: 0.23.0
> Environment: Run on a real cluster. Using the latest 0.23 build.
> Reporter: CW Chung
> Assignee: John George
> Attachments: HDFS-1907-2.patch, HDFS-1907-3.patch, HDFS-1907-4.patch,
> HDFS-1907.patch
>
>
> BlockMissingException is thrown under this test scenario:
> Two different processes doing concurrent file r/w: one read and the other
> write on the same file
> - writer keep doing file write
> - reader doing position file read from beginning of the file to the visible
> end of file, repeatedly
> The reader is basically doing:
> byteRead = in.read(currentPosition, buffer, 0, byteToReadThisRound);
> where CurrentPostion=0, buffer is a byte array buffer, byteToReadThisRound =
> 1024*10000;
> Usually it does not fail right away. I have to read, close file, re-open the
> same file a few times to create the problem. I'll pose a test program to
> repro this problem after I've cleaned up a bit my current test program.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
