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From "Paul Rogers (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (DRILL-5709) Provide a value vector method to convert a vector to nullable
Date Wed, 09 Aug 2017 01:12:00 GMT

     [ https://issues.apache.org/jira/browse/DRILL-5709?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Paul Rogers updated DRILL-5709:
-------------------------------
    Priority: Minor  (was: Major)

> 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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