hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Xiaobing Zhou (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-9924) [umbrella] Asynchronous HDFS Access
Date Wed, 11 May 2016 21:12:13 GMT

    [ https://issues.apache.org/jira/browse/HDFS-9924?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15280839#comment-15280839
] 

Xiaobing Zhou commented on HDFS-9924:
-------------------------------------

{quote}
Hmm. Is there a way for the client to wait until more async calls are available, without polling?
{quote}
Inside the polling, client could be blocked, e.g.
{code}
     for (;;) {
          try {
            Future<Void> returnFuture = adfs.rename(src, dst, Rename.OVERWRITE);
            returnFutures.put(i, returnFuture);
            break;
          } catch (AsyncCallLimitExceededException e) {
            /**
             * reached limit of async calls, fetch results of finished async
             * calls to let follow-on calls go
             */
            start = end;
            end = i;
            // call Future#get to read results of complete async calls
            waitForReturnValues(returnFutures, start, end);
          }
        }
{code}

> [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