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https://issues.apache.org/jira/browse/DRILL-5709?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16120782#comment-16120782
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ASF GitHub Bot commented on DRILL-5709:
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GitHub user paul-rogers opened a pull request:
https://github.com/apache/drill/pull/901
DRILL-5709: Provide a value vector method to convert a vector to nullable
Please see the DRILL-5709 for an explanation and example.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/paul-rogers/drill DRILL-5709
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/drill/pull/901.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #901
----
commit ced37d52d161daae333d6048150f92c181defa53
Author: Paul Rogers <[email protected]>
Date: 2017-08-09T03:04:24Z
DRILL-5709: Provide a value vector method to convert a vector to nullable
Please see the DRILL-5709 for an explanation and example.
----
> Provide a value vector method to convert a vector to nullable
> -------------------------------------------------------------
>
> Key: DRILL-5709
> URL: https://issues.apache.org/jira/browse/DRILL-5709
> Project: Apache Drill
> Issue Type: Improvement
> Reporter: Paul Rogers
> Assignee: Paul Rogers
> Priority: Minor
> Fix For: 1.12.0
>
>
> The hash agg spill work has need to convert a non-null scalar vector to the
> nullable equivalent. For efficiency, the code wishes to simply transfer the
> underlying data buffer(s), and create the required "bits" vector, rather than
> generating code that does the transfer row-by-row.
> The solution is to add a {{toNullable(ValueVector nullableVector)}} method to
> the {{ValueVector}} class, then implement it where needed.
> Since the target code only works with scalars (that is, no arrays, no maps,
> no lists), the code only handles these cases, throwing an
> {{UnsupportedOperationException}} in other cases.
> Usage:
> {code}
> ValueVector nonNullableVector = // your non-nullable vector
> MajorType type = MajorType.newBuilder(nonNullableVector.getType)
> .setMode(DataMode.OPTIONAL)
> .build();
> MaterializedField field = MaterializedField.create(name, type);
> ValueVector nullableVector = TypeHelper.getNewVector(field,
> oContext.getAllocator());
> nonNullableVector.toNullable(nullableVector);
> // Data is now in nullableVector
> {code}
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