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[SPARK-20273][SQL] Disallow Non-deterministic Filter push-down into Join Conditions

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## What changes were proposed in this pull request?
```
sql("SELECT t1.b, rand(0) as r FROM cachedData, cachedData t1 GROUP BY t1.b having r > 0.5").show()
```
We will get the following error:
```
Job aborted due to stage failure: Task 1 in stage 4.0 failed 1 times, most recent failure: Lost task 1.0 in stage 4.0 (TID 8, localhost, executor driver): java.lang.NullPointerException
	at org.apache.spark.sql.catalyst.expressions.GeneratedClass$SpecificPredicate.eval(Unknown Source)
	at org.apache.spark.sql.execution.joins.BroadcastNestedLoopJoinExec$$anonfun$org$apache$spark$sql$execution$joins$BroadcastNestedLoopJoinExec$$boundCondition$1.apply(BroadcastNestedLoopJoinExec.scala:87)
	at org.apache.spark.sql.execution.joins.BroadcastNestedLoopJoinExec$$anonfun$org$apache$spark$sql$execution$joins$BroadcastNestedLoopJoinExec$$boundCondition$1.apply(BroadcastNestedLoopJoinExec.scala:87)
	at scala.collection.Iterator$$anon$13.hasNext(Iterator.scala:463)
```
Filters could be pushed down to the join conditions by the optimizer rule `PushPredicateThroughJoin`. However, Analyzer [blocks users to add non-deterministics conditions](https://github.com/apache/spark/blob/master/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/CheckAnalysis.scala#L386-L395) (For details, see the PR https://github.com/apache/spark/pull/7535).

We should not push down non-deterministic conditions; otherwise, we need to explicitly initialize the non-deterministic expressions. This PR is to simply block it.

### How was this patch tested?
Added a test case

Author: Xiao Li <gatorsmile@gmail.com>

Closes #17585 from gatorsmile/joinRandCondition.
This commit is contained in:
Xiao Li 2017-04-10 09:15:04 -07:00
parent 5acaf8c0c6
commit fd711ea13e
2 changed files with 12 additions and 0 deletions
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2
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/predicates.scala
View file

@ -90,6 +90,8 @@ trait PredicateHelper {
* Returns true iff `expr` could be evaluated as a condition within join.
*/
protected def canEvaluateWithinJoin(expr: Expression): Boolean = expr match {
// Non-deterministic expressions are not allowed as join conditions.
case e if !e.deterministic => false
case l: ListQuery =>
// A ListQuery defines the query which we want to search in an IN subquery expression.
// Currently the only way to evaluate an IN subquery is to convert it to a

10
sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/FilterPushdownSuite.scala
View file

@ -241,6 +241,16 @@ class FilterPushdownSuite extends PlanTest {
comparePlans(optimized, correctAnswer)
}
test("joins: do not push down non-deterministic filters into join condition") {
val x = testRelation.subquery('x)
val y = testRelation1.subquery('y)
val originalQuery = x.join(y).where(Rand(10) > 5.0).analyze
val optimized = Optimize.execute(originalQuery)
comparePlans(optimized, originalQuery)
}
test("joins: push to one side after transformCondition") {
val x = testRelation.subquery('x)
val y = testRelation1.subquery('y)