beliefer commented on a change in pull request #27237: [SPARK-28330][SQL] Support ANSI SQL: result offset clause in query expression URL: https://github.com/apache/spark/pull/27237#discussion_r367368588
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/limit.scala ########## @@ -125,40 +138,92 @@ trait BaseLimitExec extends LimitExec with CodegenSupport { child.asInstanceOf[CodegenSupport].produce(ctx, this) } - override def doConsume(ctx: CodegenContext, input: Seq[ExprCode], row: ExprCode): String = { - // The counter name is already obtained by the upstream operators via `limitNotReachedChecks`. - // Here we have to inline it to not change its name. This is fine as we won't have many limit - // operators in one query. - ctx.addMutableState(CodeGenerator.JAVA_INT, countTerm, forceInline = true, useFreshName = false) - s""" - | if ($countTerm < $limit) { - | $countTerm += 1; - | ${consume(ctx, input)} - | } - """.stripMargin - } } /** - * Take the first `limit` elements of each child partition, but do not collect or shuffle them. + * Skip the first `offset` elements then take the first `limit` of the following elements in + * each child partition, but do not collect or shuffle them. */ -case class LocalLimitExec(limit: Int, child: SparkPlan) extends BaseLimitExec { +case class LocalLimitExec(limit: Int, child: SparkPlan, offset: Int = 0) extends BaseLimitExec { override def outputOrdering: Seq[SortOrder] = child.outputOrdering override def outputPartitioning: Partitioning = child.outputPartitioning + + override def doExecute(): RDD[InternalRow] = { + if (limit == Limit.INVALID_LIMIT.value) { + child.execute() + } else { + child.execute().mapPartitions { iter => iter.take(limit + offset)} Review comment: ditto ---------------------------------------------------------------- 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: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org