[
https://issues.apache.org/jira/browse/HDFS-512?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12768990#action_12768990
]
Konstantin Shvachko commented on HDFS-512:
------------------------------------------
I ran tests for HDFS and MapReduce, inculding contrib tests for both projects.
Everything worked fine with the new keys. Also talked to Devaraj, who could not
find a reason why MR would care about blocks' generation stamps.
> Set block id as the key to Block
> --------------------------------
>
> Key: HDFS-512
> URL: https://issues.apache.org/jira/browse/HDFS-512
> Project: Hadoop HDFS
> Issue Type: Improvement
> Affects Versions: 0.21.0
> Reporter: Hairong Kuang
> Assignee: Konstantin Shvachko
> Fix For: 0.21.0
>
> Attachments: blockIdAsKey.patch, blockIdAsKey.patch, blockKey.patch
>
>
> Currently the key to Block is block id + generation stamp. I would propose to
> change it to be only block id. This is based on the following properties of
> the dfs cluster:
> 1. On each datanode only one replica of block exists. Therefore there is only
> one generation of a block.
> 2. NameNode has only one entry for a block in its blocks map.
> With this change, search for a block/replica's meta information is easier
> since most of the time we know a block's id but may not know its generation
> stamp.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
