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Posted to commits@beam.apache.org by "Jean-Baptiste Onofré (JIRA)" <ji...@apache.org> on 2016/12/22 18:24:58 UTC

[jira] [Assigned] (BEAM-1206) PCollections used as a sideInput are unnecessarily re-evaluated.

     [ https://issues.apache.org/jira/browse/BEAM-1206?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jean-Baptiste Onofré reassigned BEAM-1206:
------------------------------------------

    Assignee: Jean-Baptiste Onofré  (was: Amit Sela)

> PCollections used as a sideInput are unnecessarily re-evaluated.
> ----------------------------------------------------------------
>
>                 Key: BEAM-1206
>                 URL: https://issues.apache.org/jira/browse/BEAM-1206
>             Project: Beam
>          Issue Type: Bug
>          Components: runner-spark
>    Affects Versions: 0.4.0-incubating
>            Reporter: Ryan Skraba
>            Assignee: Jean-Baptiste Onofré
>
> The SparkRunner keeps track of "leaf" transforms in the job graph and ensures that they have been executed when the pipeline is run.
> However, when a PCollection is used as a sideInput, it is evaluated *once* to get the materialized values but is still considered a leaf node.  It is evaluated a second time at the end of the Spark job, which is unnecessary (and can cause unexpected behaviour).
> One of the symptoms of this bug is that `Sink`s will create spurious writers that execute, but are never finalized.  Specifically the HDFSFileSink will _always_ die with a `Writer results and output files do not match` error.



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