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Posted to commits@spark.apache.org by li...@apache.org on 2017/07/18 04:07:54 UTC
spark git commit: [SPARK-21332][SQL] Incorrect result type inferred
for some decimal expressions
Repository: spark
Updated Branches:
refs/heads/master 5952ad2b4 -> 0be5fb41a
[SPARK-21332][SQL] Incorrect result type inferred for some decimal expressions
## What changes were proposed in this pull request?
This PR changes the direction of expression transformation in the DecimalPrecision rule. Previously, the expressions were transformed down, which led to incorrect result types when decimal expressions had other decimal expressions as their operands. The root cause of this issue was in visiting outer nodes before their children. Consider the example below:
```
val inputSchema = StructType(StructField("col", DecimalType(26, 6)) :: Nil)
val sc = spark.sparkContext
val rdd = sc.parallelize(1 to 2).map(_ => Row(BigDecimal(12)))
val df = spark.createDataFrame(rdd, inputSchema)
// Works correctly since no nested decimal expression is involved
// Expected result type: (26, 6) * (26, 6) = (38, 12)
df.select($"col" * $"col").explain(true)
df.select($"col" * $"col").printSchema()
// Gives a wrong result since there is a nested decimal expression that should be visited first
// Expected result type: ((26, 6) * (26, 6)) * (26, 6) = (38, 12) * (26, 6) = (38, 18)
df.select($"col" * $"col" * $"col").explain(true)
df.select($"col" * $"col" * $"col").printSchema()
```
The example above gives the following output:
```
// Correct result without sub-expressions
== Parsed Logical Plan ==
'Project [('col * 'col) AS (col * col)#4]
+- LogicalRDD [col#1]
== Analyzed Logical Plan ==
(col * col): decimal(38,12)
Project [CheckOverflow((promote_precision(cast(col#1 as decimal(26,6))) * promote_precision(cast(col#1 as decimal(26,6)))), DecimalType(38,12)) AS (col * col)#4]
+- LogicalRDD [col#1]
== Optimized Logical Plan ==
Project [CheckOverflow((col#1 * col#1), DecimalType(38,12)) AS (col * col)#4]
+- LogicalRDD [col#1]
== Physical Plan ==
*Project [CheckOverflow((col#1 * col#1), DecimalType(38,12)) AS (col * col)#4]
+- Scan ExistingRDD[col#1]
// Schema
root
|-- (col * col): decimal(38,12) (nullable = true)
// Incorrect result with sub-expressions
== Parsed Logical Plan ==
'Project [(('col * 'col) * 'col) AS ((col * col) * col)#11]
+- LogicalRDD [col#1]
== Analyzed Logical Plan ==
((col * col) * col): decimal(38,12)
Project [CheckOverflow((promote_precision(cast(CheckOverflow((promote_precision(cast(col#1 as decimal(26,6))) * promote_precision(cast(col#1 as decimal(26,6)))), DecimalType(38,12)) as decimal(26,6))) * promote_precision(cast(col#1 as decimal(26,6)))), DecimalType(38,12)) AS ((col * col) * col)#11]
+- LogicalRDD [col#1]
== Optimized Logical Plan ==
Project [CheckOverflow((cast(CheckOverflow((col#1 * col#1), DecimalType(38,12)) as decimal(26,6)) * col#1), DecimalType(38,12)) AS ((col * col) * col)#11]
+- LogicalRDD [col#1]
== Physical Plan ==
*Project [CheckOverflow((cast(CheckOverflow((col#1 * col#1), DecimalType(38,12)) as decimal(26,6)) * col#1), DecimalType(38,12)) AS ((col * col) * col)#11]
+- Scan ExistingRDD[col#1]
// Schema
root
|-- ((col * col) * col): decimal(38,12) (nullable = true)
```
## How was this patch tested?
This PR was tested with available unit tests. Moreover, there are tests to cover previously failing scenarios.
Author: aokolnychyi <an...@sap.com>
Closes #18583 from aokolnychyi/spark-21332.
Project: http://git-wip-us.apache.org/repos/asf/spark/repo
Commit: http://git-wip-us.apache.org/repos/asf/spark/commit/0be5fb41
Tree: http://git-wip-us.apache.org/repos/asf/spark/tree/0be5fb41
Diff: http://git-wip-us.apache.org/repos/asf/spark/diff/0be5fb41
Branch: refs/heads/master
Commit: 0be5fb41a6b7ef4da9ba36f3604ac646cb6d4ae3
Parents: 5952ad2
Author: aokolnychyi <an...@sap.com>
Authored: Mon Jul 17 21:07:50 2017 -0700
Committer: gatorsmile <ga...@gmail.com>
Committed: Mon Jul 17 21:07:50 2017 -0700
----------------------------------------------------------------------
.../apache/spark/sql/catalyst/analysis/DecimalPrecision.scala | 2 +-
.../spark/sql/catalyst/analysis/DecimalPrecisionSuite.scala | 6 ++++++
2 files changed, 7 insertions(+), 1 deletion(-)
----------------------------------------------------------------------
http://git-wip-us.apache.org/repos/asf/spark/blob/0be5fb41/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/DecimalPrecision.scala
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diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/DecimalPrecision.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/DecimalPrecision.scala
index 9c38dd2..fd2ac78 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/DecimalPrecision.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/DecimalPrecision.scala
@@ -80,7 +80,7 @@ object DecimalPrecision extends Rule[LogicalPlan] {
def apply(plan: LogicalPlan): LogicalPlan = plan resolveOperators {
// fix decimal precision for expressions
- case q => q.transformExpressions(
+ case q => q.transformExpressionsUp(
decimalAndDecimal.orElse(integralAndDecimalLiteral).orElse(nondecimalAndDecimal))
}
http://git-wip-us.apache.org/repos/asf/spark/blob/0be5fb41/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/analysis/DecimalPrecisionSuite.scala
----------------------------------------------------------------------
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/analysis/DecimalPrecisionSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/analysis/DecimalPrecisionSuite.scala
index ccf3c3f..11a4a79 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/analysis/DecimalPrecisionSuite.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/analysis/DecimalPrecisionSuite.scala
@@ -90,8 +90,14 @@ class DecimalPrecisionSuite extends AnalysisTest with BeforeAndAfter {
checkType(Average(d1), DecimalType(6, 5))
checkType(Add(Add(d1, d2), d1), DecimalType(7, 2))
+ checkType(Add(Add(d1, d1), d1), DecimalType(4, 1))
+ checkType(Add(d1, Add(d1, d1)), DecimalType(4, 1))
checkType(Add(Add(Add(d1, d2), d1), d2), DecimalType(8, 2))
checkType(Add(Add(d1, d2), Add(d1, d2)), DecimalType(7, 2))
+ checkType(Subtract(Subtract(d2, d1), d1), DecimalType(7, 2))
+ checkType(Multiply(Multiply(d1, d1), d2), DecimalType(11, 4))
+ checkType(Divide(d2, Add(d1, d1)), DecimalType(10, 6))
+ checkType(Sum(Add(d1, d1)), DecimalType(13, 1))
}
test("Comparison operations") {
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