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author | Herman van Hovell <hvanhovell@questtec.nl> | 2016-05-10 12:47:31 -0700 |
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committer | Yin Huai <yhuai@databricks.com> | 2016-05-10 12:47:31 -0700 |
commit | d28c67544b26c38d51a31d1f8dac3fc23860e1ef (patch) | |
tree | ccf2d39c55bf8e2c25177f470c1c4c839bb411f1 | |
parent | 89f73f674126bbc1cc101f0f5731b5750f1c90c8 (diff) | |
download | spark-d28c67544b26c38d51a31d1f8dac3fc23860e1ef.tar.gz spark-d28c67544b26c38d51a31d1f8dac3fc23860e1ef.tar.bz2 spark-d28c67544b26c38d51a31d1f8dac3fc23860e1ef.zip |
[SPARK-14986][SQL] Return correct result for empty LATERAL VIEW OUTER
## What changes were proposed in this pull request?
A Generate with the `outer` flag enabled should always return one or more rows for every input row. The optimizer currently violates this by rewriting `outer` Generates that do not contain columns of the child plan into an unjoined generate, for example:
```sql
select e from a lateral view outer explode(a.b) as e
```
The result of this is that `outer` Generate does not produce output at all when the Generators' input expression is empty. This PR fixes this.
## How was this patch tested?
Added test case to `SQLQuerySuite`.
Author: Herman van Hovell <hvanhovell@questtec.nl>
Closes #12906 from hvanhovell/SPARK-14986.
-rw-r--r-- | sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala | 3 | ||||
-rw-r--r-- | sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala | 7 |
2 files changed, 9 insertions, 1 deletions
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala index a3ab89dc71..350b60134e 100644 --- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala +++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala @@ -362,7 +362,8 @@ object ColumnPruning extends Rule[LogicalPlan] { g.copy(child = prunedChild(g.child, g.references)) // Turn off `join` for Generate if no column from it's child is used - case p @ Project(_, g: Generate) if g.join && p.references.subsetOf(g.generatedSet) => + case p @ Project(_, g: Generate) + if g.join && !g.outer && p.references.subsetOf(g.generatedSet) => p.copy(child = g.copy(join = false)) // Eliminate unneeded attributes from right side of a Left Existence Join. diff --git a/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala index e401abef29..4ef4b4865f 100644 --- a/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala +++ b/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala @@ -2473,4 +2473,11 @@ class SQLQuerySuite extends QueryTest with SharedSQLContext { Row("r3c1x", "r3c2", "t1r3c3", "r3c2", "t1r3c3") :: Nil) } } + + test("SPARK-14986: Outer lateral view with empty generate expression") { + checkAnswer( + sql("select nil from (select 1 as x ) x lateral view outer explode(array()) n as nil"), + Row(null) :: Nil + ) + } } |