You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@flink.apache.org by "ASF GitHub Bot (JIRA)" <ji...@apache.org> on 2016/12/12 11:05:58 UTC
[jira] [Commented] (FLINK-3257) Add Exactly-Once Processing
Guarantees in Iterative DataStream Jobs
[ https://issues.apache.org/jira/browse/FLINK-3257?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15741633#comment-15741633 ]
ASF GitHub Bot commented on FLINK-3257:
---------------------------------------
Github user senorcarbone commented on the issue:
https://github.com/apache/flink/pull/1668
Hey again, @StephanEwen @uce .
When you have 10 min can you take a look to see if this is acceptable?
I would not like to leave this here for months again, it has been out way too long already.
The changes are just a few and straightforward so I really encourage you to skim them at your earliest convenience. Thanks!
> Add Exactly-Once Processing Guarantees in Iterative DataStream Jobs
> -------------------------------------------------------------------
>
> Key: FLINK-3257
> URL: https://issues.apache.org/jira/browse/FLINK-3257
> Project: Flink
> Issue Type: Improvement
> Reporter: Paris Carbone
> Assignee: Paris Carbone
>
> The current snapshotting algorithm cannot support cycles in the execution graph. An alternative scheme can potentially include records in-transit through the back-edges of a cyclic execution graph (ABS [1]) to achieve the same guarantees.
> One straightforward implementation of ABS for cyclic graphs can work as follows along the lines:
> 1) Upon triggering a barrier in an IterationHead from the TaskManager start block output and start upstream backup of all records forwarded from the respective IterationSink.
> 2) The IterationSink should eventually forward the current snapshotting epoch barrier to the IterationSource.
> 3) Upon receiving a barrier from the IterationSink, the IterationSource should finalize the snapshot, unblock its output and emit all records in-transit in FIFO order and continue the usual execution.
> --
> Upon restart the IterationSource should emit all records from the injected snapshot first and then continue its usual execution.
> Several optimisations and slight variations can be potentially achieved but this can be the initial implementation take.
> [1] http://arxiv.org/abs/1506.08603
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)