Github user marmbrus commented on a diff in the pull request: https://github.com/apache/spark/pull/2262#discussion_r17096919 --- Diff: sql/core/src/main/scala/org/apache/spark/sql/execution/basicOperators.scala --- @@ -97,6 +97,7 @@ case class Limit(limit: Int, child: SparkPlan) // partition local limit -> exchange into one partition -> partition local limit again override def output = child.output + override def outputPartitioning = SinglePartition --- End diff -- This is not changing the implementation, just correcting a bug that prevents exchange operators from being inserted when we need them. On Sep 3, 2014 11:00 PM, "Cheng Hao" <notificati...@github.com> wrote: > In > sql/core/src/main/scala/org/apache/spark/sql/execution/basicOperators.scala: > > > @@ -97,6 +97,7 @@ case class Limit(limit: Int, child: SparkPlan) > > // partition local limit -> exchange into one partition -> partition local limit again > > > > override def output = child.output > > + override def outputPartitioning = SinglePartition > > SinglePartition for LIMIT may cause performance issue for large number of > records(in multiple partitions), do we really need to change this? > > â > Reply to this email directly or view it on GitHub > <https://github.com/apache/spark/pull/2262/files#r17096863>. >
--- If your project is set up for it, you can reply to this email and have your reply appear on GitHub as well. If your project does not have this feature enabled and wishes so, or if the feature is enabled but not working, please contact infrastructure at infrastruct...@apache.org or file a JIRA ticket with INFRA. --- --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org