hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Colin Patrick McCabe (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-9924) [umbrella] Asynchronous HDFS Access
Date Fri, 20 May 2016 17:37:13 GMT

    [ https://issues.apache.org/jira/browse/HDFS-9924?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15293809#comment-15293809
] 

Colin Patrick McCabe commented on HDFS-9924:
--------------------------------------------

I have to agree with [~andrew.wang] that it makes more sense to put these changes in trunk
than in branch-2.  The Hadoop 2.8 release has been blocked for a very, very long time.  There
are tons of features in branch-2 that have been waiting for almost a year to be released.
 Adding yet another feature to branch-2, when we're so far behind on releases, doesn't make
sense.

Programmers who are familiar with Node.js will want something that supports callback chaining,
like CompletableFuture, rather than something like the old-style Future API.  If we target
this at branch-3, we can use the jdk8 CompletableFuture.

If we are going to backport this to branch-2, we should do it once the feature is done, rather
than backporting bits and pieces as we go.  This is especially true when there are still open
questions about the API.

> [umbrella] Asynchronous HDFS Access
> -----------------------------------
>
>                 Key: HDFS-9924
>                 URL: https://issues.apache.org/jira/browse/HDFS-9924
>             Project: Hadoop HDFS
>          Issue Type: New Feature
>          Components: fs
>            Reporter: Tsz Wo Nicholas Sze
>            Assignee: Xiaobing Zhou
>         Attachments: AsyncHdfs20160510.pdf
>
>
> This is an umbrella JIRA for supporting Asynchronous HDFS Access.
> Currently, all the API methods are blocking calls -- the caller is blocked until the
method returns.  It is very slow if a client makes a large number of independent calls in
a single thread since each call has to wait until the previous call is finished.  It is inefficient
if a client needs to create a large number of threads to invoke the calls.
> We propose adding a new API to support asynchronous calls, i.e. the caller is not blocked.
 The methods in the new API immediately return a Java Future object.  The return value can
be obtained by the usual Future.get() method.



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

---------------------------------------------------------------------
To unsubscribe, e-mail: hdfs-issues-unsubscribe@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-help@hadoop.apache.org


Mime
View raw message