crunch-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Mikael Goldmann (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CRUNCH-601) Short PCollections in SparkPipeline get length null.
Date Wed, 17 Aug 2016 15:57:20 GMT

    [ https://issues.apache.org/jira/browse/CRUNCH-601?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15424778#comment-15424778
] 

Mikael Goldmann commented on CRUNCH-601:
----------------------------------------

Oh, right, the fact that we emit something in cleanup() has no effect on the size estimate,
so we still short circuit away materializing the collection. Isn't it a bit dangerous to treat
getSize() == 0 as a guarantee that the collection is empty?

> Short PCollections in SparkPipeline get length null.
> ----------------------------------------------------
>
>                 Key: CRUNCH-601
>                 URL: https://issues.apache.org/jira/browse/CRUNCH-601
>             Project: Crunch
>          Issue Type: Bug
>          Components: Spark
>    Affects Versions: 0.13.0
>         Environment: Running in local mode on Mac as well as in a ubuntu 14.04 docker
container
>            Reporter: Mikael Goldmann
>            Priority: Minor
>         Attachments: CRUNCH-601.patch, SmallCollectionLengthTest.java
>
>
> I'll attach a file with a test that I would expect to pass but which fails.
> It creates five PCollection<String> of lengths 0, 1, 2, 3, 4 gets the lengths,
runs the pipeline and prints the lengths. Finally it asserts that all lengths are non-null.
> I would expect it to print lengths 0, 1, 2, 3, 4 and pass.
> What it does is print lengths null, null, null, 3, 4 and fail.
> I think the underlying reason is the use of getSize() on an unmaterialized object and
assuming that when the estimate that getSize() returns is 0, then the PCollection is guaranteed
to be empty, which is false in some cases.



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

Mime
View raw message