hadoop-common-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Doug Cutting (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-894) dfs client protocol should allow asking for parts of the block map
Date Wed, 09 May 2007 22:14:15 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-894?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12494587
] 

Doug Cutting commented on HADOOP-894:
-------------------------------------

Konstantin: Does LocatedBlocks contain the length of the file?  We need that too, don't we?
 Also, why have an open() method at all, rather than just using open(start,length), letting
the client pass start=0 and length=${hdfs.initial.bytes}?

> dfs client protocol should allow asking for parts of the block map
> ------------------------------------------------------------------
>
>                 Key: HADOOP-894
>                 URL: https://issues.apache.org/jira/browse/HADOOP-894
>             Project: Hadoop
>          Issue Type: Improvement
>          Components: dfs
>            Reporter: Owen O'Malley
>         Assigned To: Konstantin Shvachko
>         Attachments: partialBlockList.patch, partialBlockList2.patch
>
>
> I think that the HDFS client protocol should change like:
> /** The meta-data about a file that was opened. */
> class OpenFileInfo {
>   /** the info for the first block */
>   public LocatedBlockInfo getBlockInfo();
>   public long getBlockSize();
>   public long getLength();
> }
> interface ClientProtocol extends VersionedProtocol {
>   public OpenFileInfo open(String name) throws IOException;
>   /** get block info for any range of blocks */
>   public LocatedBlockInfo[] getBlockInfo(String name, int blockOffset, int blockLength)
throws IOException;
> }
> so that the client can decide how much block info to request and when. Currently, when
the file is opened or an error occurs, the entire block list is requested and sent.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message