[ 
https://issues.apache.org/jira/browse/HDFS-1783?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13294094#comment-13294094
 ] 

Zhihong Ted Yu commented on HDFS-1783:
--------------------------------------

{code}
  public FSDataOutputStream create(Path f,
      FsPermission permission,
      EnumSet<CreateFlag> flags,
      int bufferSize,
      short replication,
      long blockSize,
      Progressable progress) throws IOException {
{code}
The above method only respects CreateFlag.OVERWRITE:
{code}
    return create(f, permission, flags.contains(CreateFlag.OVERWRITE), 
bufferSize, replication, blockSize, progress);
{code}
This method calls append if CreateFlag.APPEND is specified:
{code}
  protected FSDataOutputStream primitiveCreate(Path f,
     FsPermission absolutePermission, EnumSet<CreateFlag> flag, int bufferSize,
     short replication, long blockSize, Progressable progress,
     int bytesPerChecksum) throws IOException {
{code}

                
> Ability for HDFS client to write replicas in parallel
> -----------------------------------------------------
>
>                 Key: HDFS-1783
>                 URL: https://issues.apache.org/jira/browse/HDFS-1783
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: hdfs client
>            Reporter: dhruba borthakur
>            Assignee: Lars Hofhansl
>         Attachments: HDFS-1783-trunk-v2.patch, HDFS-1783-trunk-v3.patch, 
> HDFS-1783-trunk-v4.patch, HDFS-1783-trunk-v5.patch, HDFS-1783-trunk.patch
>
>
> The current implementation of HDFS pipelines the writes to the three 
> replicas. This introduces some latency for realtime latency sensitive 
> applications. An alternate implementation that allows the client to write all 
> replicas in parallel gives much better response times to these applications. 

--
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

        

Reply via email to