[
https://issues.apache.org/jira/browse/HDFS-9144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14969191#comment-14969191
]
Bob Hansen commented on HDFS-9144:
----------------------------------
Thanks for the feedback; [~wheat9]: you are correct, the RpcEngine is owned by
the NNConnection.
By "familiar", I mean an easy path for those who are used to POSIX file
semantics: open a file, sequential reads, seeks, close a file. We will, of
course, also support parallel asynchronous positional reads, but I think we
want a nice clean interface for POSIX-y semantics.
Let's break the work down into smaller pieces. I started with abstracting out
the NN connection in the attached patch. I will work on abstracting the DN
connection next.
> Refactor libhdfs into stateful/ephemeral objects
> ------------------------------------------------
>
> Key: HDFS-9144
> URL: https://issues.apache.org/jira/browse/HDFS-9144
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: hdfs-client
> Affects Versions: HDFS-8707
> Reporter: Bob Hansen
> Assignee: Bob Hansen
> Attachments: HDFS-9144.HDFS-8707.001.patch
>
>
> In discussion for other efforts, we decided that we should separate several
> concerns:
> * A posix-like FileSystem/FileHandle object (stream-based, positional reads)
> * An ephemeral ReadOperation object that holds the state for
> reads-in-progress, which consumes
> * An immutable FileInfo object which holds the block map and file size (and
> other metadata about the file that we assume will not change over the life of
> the file)
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
