[
https://issues.apache.org/jira/browse/CRUNCH-237?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Josh Wills updated CRUNCH-237:
------------------------------
Attachment: CRUNCH-237.patch
The patch. I will submit it in the next few minutes.
> Improper job dependencies for certain types of long pipelines
> -------------------------------------------------------------
>
> Key: CRUNCH-237
> URL: https://issues.apache.org/jira/browse/CRUNCH-237
> Project: Crunch
> Issue Type: Bug
> Components: Core
> Affects Versions: 0.6.0
> Reporter: Josh Wills
> Assignee: Josh Wills
> Fix For: 0.7.0
>
> Attachments: CRUNCH-237.patch
>
>
> The Crunch planner analyzes the dependencies between different phases of a
> MapReduce pipeline and uses those dependencies to ensure that the MapReduce
> jobs in the pipeline are executed in the correct sequence. For certain kinds
> of long pipelines, it's possible for the planner to miss a necessary
> dependency as follows:
> Pipeline spec: [Input] -> GBK -> [Out1] -> (GBK) -> (Out2) -> GBK -> [Out3]
> This pipeline has two explicit outputs (Out1 and Out3) and one implicit
> output (Out2). Additionally, assume that there is a map-side join between
> Out1 that happens in the map stage of the job that creates Out2. For this
> pipeline, the planner will mark a dependency between the job that creates
> Out1 and the job that creates Out3, but NOT between the job that creates Out1
> and the job that creates Out2. This makes it possible for the Out2 job to run
> before Out1 is created, causing a failure.
> The easiest way to fix this I could see was to add a step to the dependency
> chain such that every job that is created in a later stage of pipeline
> creation depends on all of the jobs in the earlier stages having been run,
> which is what the attached patch and example integration test demonstrate.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
