Github user viirya commented on a diff in the pull request: https://github.com/apache/spark/pull/18955#discussion_r133465091 --- Diff: sql/core/src/main/scala/org/apache/spark/sql/execution/limit.scala --- @@ -54,6 +54,16 @@ trait BaseLimitExec extends UnaryExecNode with CodegenSupport { val limit: Int override def output: Seq[Attribute] = child.output + // Do not enable whole stage codegen for a single limit. + override def supportCodegen: Boolean = child match { + case plan: CodegenSupport => plan.supportCodegen + case _ => false + } + + override def executeTake(n: Int): Array[InternalRow] = child.executeTake(math.min(n, limit)) + + override def executeCollect(): Array[InternalRow] = child.executeTake(limit) --- End diff -- `executeTake` looks good. But should `executeCollect` be the same for `LocalLimitExec` and `GlobalLimitExec`? `doExecute` is an example. For `LocalLimitExec`, it takes `limit` rows in each partition. For `GlobalLimitExec`, it takes `limit` rows in single partition. Previously `executeCollect` retrieves `limit` rows from each partition. After this change, `executeCollect` for `LocalLimitExec` retrieves only `limit` rows.
--- 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