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author | Takeshi YAMAMURO <linguin.m.s@gmail.com> | 2016-06-01 22:23:00 -0700 |
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committer | Cheng Lian <lian@databricks.com> | 2016-06-01 22:23:00 -0700 |
commit | 5eea332307cbed5fc44427959f070afc16a12c02 (patch) | |
tree | 8f2cc80645a769fa7908615da3b5c590af8eeab7 | |
parent | 8288e16a5a5a12a45207c13a1341c707c6b4b940 (diff) | |
download | spark-5eea332307cbed5fc44427959f070afc16a12c02.tar.gz spark-5eea332307cbed5fc44427959f070afc16a12c02.tar.bz2 spark-5eea332307cbed5fc44427959f070afc16a12c02.zip |
[SPARK-13484][SQL] Prevent illegal NULL propagation when filtering outer-join results
## What changes were proposed in this pull request?
This PR add a rule at the end of analyzer to correct nullable fields of attributes in a logical plan by using nullable fields of the corresponding attributes in its children logical plans (these plans generate the input rows).
This is another approach for addressing SPARK-13484 (the first approach is https://github.com/apache/spark/pull/11371).
Close #113711
Author: Takeshi YAMAMURO <linguin.m.s@gmail.com>
Author: Yin Huai <yhuai@databricks.com>
Closes #13290 from yhuai/SPARK-13484.
3 files changed, 58 insertions, 2 deletions
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala index eb46c0e72e..02966796af 100644 --- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala +++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala @@ -113,6 +113,8 @@ class Analyzer( PullOutNondeterministic), Batch("UDF", Once, HandleNullInputsForUDF), + Batch("FixNullability", Once, + FixNullability), Batch("Cleanup", fixedPoint, CleanupAliases) ) @@ -1452,6 +1454,40 @@ class Analyzer( } /** + * Fixes nullability of Attributes in a resolved LogicalPlan by using the nullability of + * corresponding Attributes of its children output Attributes. This step is needed because + * users can use a resolved AttributeReference in the Dataset API and outer joins + * can change the nullability of an AttribtueReference. Without the fix, a nullable column's + * nullable field can be actually set as non-nullable, which cause illegal optimization + * (e.g., NULL propagation) and wrong answers. + * See SPARK-13484 and SPARK-13801 for the concrete queries of this case. + */ + object FixNullability extends Rule[LogicalPlan] { + + def apply(plan: LogicalPlan): LogicalPlan = plan transformUp { + case p if !p.resolved => p // Skip unresolved nodes. + case p: LogicalPlan if p.resolved => + val childrenOutput = p.children.flatMap(c => c.output).groupBy(_.exprId).flatMap { + case (exprId, attributes) => + // If there are multiple Attributes having the same ExprId, we need to resolve + // the conflict of nullable field. We do not really expect this happen. + val nullable = attributes.exists(_.nullable) + attributes.map(attr => attr.withNullability(nullable)) + }.toSeq + // At here, we create an AttributeMap that only compare the exprId for the lookup + // operation. So, we can find the corresponding input attribute's nullability. + val attributeMap = AttributeMap[Attribute](childrenOutput.map(attr => attr -> attr)) + // For an Attribute used by the current LogicalPlan, if it is from its children, + // we fix the nullable field by using the nullability setting of the corresponding + // output Attribute from the children. + p.transformExpressions { + case attr: Attribute if attributeMap.contains(attr) => + attr.withNullability(attributeMap(attr).nullable) + } + } + } + + /** * Extracts [[WindowExpression]]s from the projectList of a [[Project]] operator and * aggregateExpressions of an [[Aggregate]] operator and creates individual [[Window]] * operators for every distinct [[WindowSpecDefinition]]. @@ -2133,4 +2169,3 @@ object TimeWindowing extends Rule[LogicalPlan] { } } } - diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/analysis/ResolveNaturalJoinSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/analysis/ResolveNaturalJoinSuite.scala index 1423a8705a..748579df41 100644 --- a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/analysis/ResolveNaturalJoinSuite.scala +++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/analysis/ResolveNaturalJoinSuite.scala @@ -100,7 +100,7 @@ class ResolveNaturalJoinSuite extends AnalysisTest { val naturalPlan = r3.join(r4, NaturalJoin(FullOuter), None) val usingPlan = r3.join(r4, UsingJoin(FullOuter, Seq(UnresolvedAttribute("b"))), None) val expected = r3.join(r4, FullOuter, Some(EqualTo(bNotNull, bNotNull))).select( - Alias(Coalesce(Seq(bNotNull, bNotNull)), "b")(), a, c) + Alias(Coalesce(Seq(b, b)), "b")(), a, c) checkAnalysis(naturalPlan, expected) checkAnalysis(usingPlan, expected) } diff --git a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameJoinSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameJoinSuite.scala index 031e66b57c..4342c039ae 100644 --- a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameJoinSuite.scala +++ b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameJoinSuite.scala @@ -204,4 +204,25 @@ class DataFrameJoinSuite extends QueryTest with SharedSQLContext { leftJoin2Inner, Row(1, 2, "1", 1, 3, "1") :: Nil) } + + test("process outer join results using the non-nullable columns in the join input") { + // Filter data using a non-nullable column from a right table + val df1 = Seq((0, 0), (1, 0), (2, 0), (3, 0), (4, 0)).toDF("id", "count") + val df2 = Seq(Tuple1(0), Tuple1(1)).toDF("id").groupBy("id").count + checkAnswer( + df1.join(df2, df1("id") === df2("id"), "left_outer").filter(df2("count").isNull), + Row(2, 0, null, null) :: + Row(3, 0, null, null) :: + Row(4, 0, null, null) :: Nil + ) + + // Coalesce data using non-nullable columns in input tables + val df3 = Seq((1, 1)).toDF("a", "b") + val df4 = Seq((2, 2)).toDF("a", "b") + checkAnswer( + df3.join(df4, df3("a") === df4("a"), "outer") + .select(coalesce(df3("a"), df3("b")), coalesce(df4("a"), df4("b"))), + Row(1, null) :: Row(null, 2) :: Nil + ) + } } |