beliefer commented on a change in pull request #27058: [SPARK-30276][SQL]
Support Filter expression allows simultaneous use of DISTINCT
URL: https://github.com/apache/spark/pull/27058#discussion_r371085072
##########
File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/RewriteDistinctAggregates.scala
##########
@@ -148,24 +207,106 @@ object RewriteDistinctAggregates extends
Rule[LogicalPlan] {
val distinctAggs = exprs.flatMap { _.collect {
case ae: AggregateExpression if ae.isDistinct => ae
}}
- // We need at least two distinct aggregates for this rule because
aggregation
- // strategy can handle a single distinct group.
+ // This rule serves two purposes:
+ // One is to rewrite when there exists at least two distinct aggregates.
We need at least
+ // two distinct aggregates for this rule because aggregation strategy can
handle a single
+ // distinct group.
+ // Another is to expand distinct aggregates which exists filter clause so
that we can
+ // evaluate the filter locally.
// This check can produce false-positives, e.g., SUM(DISTINCT a) &
COUNT(DISTINCT a).
- distinctAggs.size > 1
+ distinctAggs.size >= 1 || distinctAggs.exists(_.filter.isDefined)
}
def apply(plan: LogicalPlan): LogicalPlan = plan transformUp {
- case a: Aggregate if mayNeedtoRewrite(a.aggregateExpressions) => rewrite(a)
+ case a: Aggregate if mayNeedtoRewrite(a.aggregateExpressions) =>
+ val expandAggregate = extractFiltersInDistinctAggregate(a)
+ rewriteDistinctAggregate(expandAggregate)
}
- def rewrite(a: Aggregate): Aggregate = {
+ private def extractFiltersInDistinctAggregate(a: Aggregate): Aggregate = {
Review comment:
OK
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
[email protected]
With regards,
Apache Git Services
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
