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https://issues.apache.org/jira/browse/CRUNCH-601?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Micah Whitacre updated CRUNCH-601:
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Attachment: CRUNCH-601c.patch
Corrected LengthPObject spelling.
[~jwills]
{quote}
I don't quite follow the reasoning behind returning the parentSize value if
newSize == 0 instead of e.g. returning Math.max(1L, newSize)?
{quote}
Mikael answered similar to my reasoning. Size is typically used for two
reasons:
* Making decisions about when the planner should write out data vs not
* Planning for skipping processing if there is no data to process.
Since small sizes like 1-100 won't matter much for the planner, really we just
need to be accurate about 0 or not.
That's the reason for looking at the parent size up the stack.
> 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
> Assignee: Micah Whitacre
> Priority: Minor
> Attachments: CRUNCH-601.patch, CRUNCH-601b.patch, CRUNCH-601c.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.
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