Github user chenghao-intel commented on a diff in the pull request:
https://github.com/apache/spark/pull/7446#discussion_r34855419
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
---
@@ -513,18 +513,28 @@ object SimplifyFilters extends Rule[LogicalPlan] {
object PushPredicateThroughProject extends Rule[LogicalPlan] {
def apply(plan: LogicalPlan): LogicalPlan = plan transform {
case filter @ Filter(condition, project @ Project(fields, grandChild))
=>
- val sourceAliases = fields.collect { case a @ Alias(c, _) =>
- (a.toAttribute: Attribute) -> c
- }.toMap
- project.copy(child = filter.copy(
- replaceAlias(condition, sourceAliases),
- grandChild))
- }
+ // Create a map of Aliases to their values from the child projection.
+ // e.g., 'SELECT a + b AS c, d ...' produces Map(c -> a + b).
+ val aliasMap = AttributeMap(fields.collect {
+ case a: Alias => (a.toAttribute, a.child)
+ })
- private def replaceAlias(condition: Expression, sourceAliases:
Map[Attribute, Expression]) = {
- condition transform {
- case a: AttributeReference => sourceAliases.getOrElse(a, a)
- }
+ // We only push down filter if their overlapped expressions are all
+ // deterministic.
+ val hasNondeterministic = condition.collect {
+ case a: Attribute if aliasMap.contains(a) => aliasMap(a)
+ }.exists(_.find(!_.deterministic).isDefined)
+
+ if (hasNondeterministic) {
+ filter
--- End diff --
We still can push down the deterministic part. For example:
```
testRelation
.where('a > 5)
.select(Rand(10).as('rand), 'a)
.where('rand > 5 and 'a > 8)
```
==>
```
testRelation
.where('a > 5)
.where('a>8)
.select(Rand(10).as('rand), 'a)
.where('rand > 5)
```
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