flink-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FLINK-909) Pitfall due to additional superstep after the iteration has stopped
Date Thu, 07 Aug 2014 20:33:13 GMT

    [ https://issues.apache.org/jira/browse/FLINK-909?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14089784#comment-14089784
] 

ASF GitHub Bot commented on FLINK-909:
--------------------------------------

GitHub user StephanEwen opened a pull request:

    https://github.com/apache/incubator-flink/pull/91

    [FLINK-909], [FLINK945] Remove additional superstep at the end of iterrations

    Fixes simultaneously the pitfall reported in [FLINK-909] and the memory release bug reported
in [FLINK-945].

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/StephanEwen/incubator-flink iterbug

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/incubator-flink/pull/91.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #91
    
----
commit 76a48df00f0fc202bdedefb33d576fd9a18a92c0
Author: Stephan Ewen <sewen@apache.org>
Date:   2014-08-07T20:00:51Z

    [FLINK-909]  Remove additional empty (and non empty for iterative broadcast variables)
superstep.
    [FLINK-945]  Fix early memory release in iterations

----


> Pitfall due to additional superstep after the iteration has stopped
> -------------------------------------------------------------------
>
>                 Key: FLINK-909
>                 URL: https://issues.apache.org/jira/browse/FLINK-909
>             Project: Flink
>          Issue Type: Bug
>            Reporter: GitHub Import
>            Assignee: Markus Holzemer
>              Labels: github-import
>             Fix For: pre-apache
>
>
> Currently, after an iteration has exceeded the maximum number of iterations, all tasks
are started again for an additional superstep during which they are stopped. This works if
a tasks only waits for dynamic input. However, in the case where one has a task, e.g. a coGroup
operation, which gets dynamic and static input the execution is not blocked. This can then
lead to erroneous behaviour which the user is not aware of.
> I had this problem implementing ALS. Here one has a loop which gets as dynamic input
matrix columns and as static input matrix entries. The columns and the entries are used to
construct a matrix which represents a system of linear equations. If the set of columns are
empty, then the matrix is singular and thus not solvable. During the additional superstep
the task won't receive any columns but would still try to solve the now singular matrix.
> It would be good to finish the iteration without initiating this additional superstep.
> ---------------- Imported from GitHub ----------------
> Url: https://github.com/stratosphere/stratosphere/issues/909
> Created by: [tillrohrmann|https://github.com/tillrohrmann]
> Labels: 
> Created at: Thu Jun 05 17:50:17 CEST 2014
> State: open



--
This message was sent by Atlassian JIRA
(v6.2#6252)

Mime
View raw message