viirya commented on a change in pull request #34701: URL: https://github.com/apache/spark/pull/34701#discussion_r758616810
########## File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala ########## @@ -2162,6 +2163,74 @@ object RemoveLiteralFromGroupExpressions extends Rule[LogicalPlan] { } } +/** + * Prunes unnecessary fields from a [[Generate]] if it is under a count aggregation + * query. + */ +object CountAggregateOptimization extends Rule[LogicalPlan] { + private def isLiteralCountAggFun(func: AggregateFunction): Boolean = func match { + case c: Count if c.children.size == 1 && c.children(0).isInstanceOf[Literal] => true + case _ => false + } + + private def isCandidate(agg: Aggregate): Boolean = { + if (agg.aggregateExpressions.size == 1) { + agg.aggregateExpressions(0) match { + case Alias(ae: AggregateExpression, _) if isLiteralCountAggFun(ae.aggregateFunction) => + true + case _ => + false + } + } else { + false + } + } + + private def pruningFields(agg: Aggregate): LogicalPlan = { + agg.transformDownWithPruning(_.containsPattern(GENERATE), ruleId) { + case p @ Project(_, g: Generate) if p.references.intersect(g.outputSet).isEmpty Review comment: For the example query, the optimized query plan has the `Project`. I think it is because column pruning. -- 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. To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org