hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "jiraposter@reviews.apache.org (Commented) (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-2834) ByteBuffer-based read API for DFSInputStream
Date Tue, 20 Mar 2012 01:29:48 GMT

    [ https://issues.apache.org/jira/browse/HDFS-2834?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13233095#comment-13233095
] 

jiraposter@reviews.apache.org commented on HDFS-2834:
-----------------------------------------------------


-----------------------------------------------------------
This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/4212/#review6103
-----------------------------------------------------------


Real close now!


hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/BlockReaderLocal.java
<https://reviews.apache.org/r/4212/#comment13128>

    this comment seems like it's in the wrong spot, since the code that comes after it doesn't
reference offsetFromChunkBoundary.



hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestBlockReaderLocal.java
<https://reviews.apache.org/r/4212/#comment13130>

    shouldn't this be true?



hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestBlockReaderLocal.java
<https://reviews.apache.org/r/4212/#comment13132>

    no reason to use DFSClient here. Instead you can just use the filesystem, right? Then
downcast the stream you get back?



hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestBlockReaderLocal.java
<https://reviews.apache.org/r/4212/#comment13131>

    don't you want an assert on sawException here? You can also use GenericTestUtils.assertExceptionContains()
if you want to check the text of it


- Todd


On 2012-03-09 00:47:24, Henry Robinson wrote:
bq.  
bq.  -----------------------------------------------------------
bq.  This is an automatically generated e-mail. To reply, visit:
bq.  https://reviews.apache.org/r/4212/
bq.  -----------------------------------------------------------
bq.  
bq.  (Updated 2012-03-09 00:47:24)
bq.  
bq.  
bq.  Review request for hadoop-hdfs and Todd Lipcon.
bq.  
bq.  
bq.  Summary
bq.  -------
bq.  
bq.  New patch for HDFS-2834 (I can't update the old review request).
bq.  
bq.  
bq.  This addresses bug HDFS-2834.
bq.      http://issues.apache.org/jira/browse/HDFS-2834
bq.  
bq.  
bq.  Diffs
bq.  -----
bq.  
bq.    hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/BlockReader.java
dfab730 
bq.    hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/BlockReaderLocal.java
cc61697 
bq.    hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java
4187f1c 
bq.    hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java
2b817ff 
bq.    hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/RemoteBlockReader.java
b7da8d4 
bq.    hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/RemoteBlockReader2.java
ea24777 
bq.    hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/BlockReaderTestUtil.java
9d4f4a2 
bq.    hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestBlockReaderLocal.java
PRE-CREATION 
bq.    hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestParallelRead.java
bbd0012 
bq.    hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestShortCircuitLocalRead.java
eb2a1d8 
bq.  
bq.  Diff: https://reviews.apache.org/r/4212/diff
bq.  
bq.  
bq.  Testing
bq.  -------
bq.  
bq.  
bq.  Thanks,
bq.  
bq.  Henry
bq.  
bq.


                
> ByteBuffer-based read API for DFSInputStream
> --------------------------------------------
>
>                 Key: HDFS-2834
>                 URL: https://issues.apache.org/jira/browse/HDFS-2834
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>            Reporter: Henry Robinson
>            Assignee: Henry Robinson
>         Attachments: HDFS-2834-no-common.patch, HDFS-2834.3.patch, HDFS-2834.4.patch,
HDFS-2834.5.patch, HDFS-2834.6.patch, HDFS-2834.7.patch, HDFS-2834.8.patch, HDFS-2834.9.patch,
HDFS-2834.patch, HDFS-2834.patch, hdfs-2834-libhdfs-benchmark.png
>
>
> The {{DFSInputStream}} read-path always copies bytes into a JVM-allocated {{byte[]}}.
Although for many clients this is desired behaviour, in certain situations, such as native-reads
through libhdfs, this imposes an extra copy penalty since the {{byte[]}} needs to be copied
out again into a natively readable memory area. 
> For these cases, it would be preferable to allow the client to supply its own buffer,
wrapped in a {{ByteBuffer}}, to avoid that final copy overhead. 

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Mime
View raw message