[jira] [Comment Edited] (HDFS-8203) Erasure Coding: Seek and other Ops in DFSStripedInputStream.

["Yi Liu (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HDFS-8203?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14529735#comment-14529735 ] 

Yi Liu edited comment on HDFS-8203 at 5/6/15 1:47 AM:
------------------------------------------------------

Update the patch.

Currently we have the {{curStripedBuf}}, so {{seek}} could be simpler.  I update the logic of {{readOneStripe}}.

In {{readOneStripe}}, we try to read striped group cells to fill the buffer. But if seek happens, the target pos can be at the middle of striped group cells:
# We don't need to fetch all striped group cells, just need to start from the cell contains the target pos.

The tests passed in my local env.


was (Author: hitliuyi):
Update the patch.

Current we have the {{curStripedBuf}}, so {{seek}} could be simpler.  I update the logic of {{readOneStripe}}.

In {{readOneStripe}}, we try to read striped group cells to fill the buffer. But if seek happens, the target pos can be at the middle of striped group cells:
# We don't need to fetch all striped group cells, just need to start from the cell contains the target pos.

The tests passed in my local env.

> Erasure Coding: Seek and other Ops in DFSStripedInputStream.
> ------------------------------------------------------------
>
>                 Key: HDFS-8203
>                 URL: https://issues.apache.org/jira/browse/HDFS-8203
>             Project: Hadoop HDFS
>          Issue Type: Sub-task
>            Reporter: Yi Liu
>            Assignee: Yi Liu
>         Attachments: HDFS-8203.001.patch, HDFS-8203.002.patch
>
>
> In HDFS-7782 and HDFS-8033, we handle pread and stateful read for {{DFSStripedInputStream}}, we also need handle other operations, such as {{seek}}, zerocopy read ...



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)