beam-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Ryan Skraba (JIRA)" <j...@apache.org>
Subject [jira] [Created] (BEAM-1206) PCollections used as a sideInput are unnecessarily re-evaluated.
Date Thu, 22 Dec 2016 16:46:58 GMT
Ryan Skraba created BEAM-1206:
---------------------------------

             Summary: 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: Amit Sela


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.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message