karuppayya commented on code in PR #4519: URL: https://github.com/apache/datafusion-comet/pull/4519#discussion_r3350783651
########## spark/src/main/scala/org/apache/comet/rules/RevertNativeForTransitionHeavyStages.scala: ########## @@ -0,0 +1,147 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +package org.apache.comet.rules + +import org.apache.spark.internal.Logging +import org.apache.spark.sql.SparkSession +import org.apache.spark.sql.catalyst.rules.Rule +import org.apache.spark.sql.comet.{CometColumnarToRowExec, CometExec, CometNativeColumnarToRowExec, CometSparkToColumnarExec} +import org.apache.spark.sql.comet.execution.shuffle.CometShuffleExchangeExec +import org.apache.spark.sql.execution.{ColumnarToRowExec, ColumnarToRowTransition, RowToColumnarExec, SparkPlan} +import org.apache.spark.sql.execution.adaptive.QueryStageExec +import org.apache.spark.sql.execution.exchange.{BroadcastExchangeLike, ShuffleExchangeLike} + +import org.apache.comet.CometConf + +/** + * Reverts a query stage to Spark row-based execution when it has too many columnar-to-row (C2R) + * transitions. Each C2R indicates Comet could not keep execution columnar and had to fall back. + * With columnar shuffle enabled, each C2R implies a corresponding R2C round-trip. + */ +case class RevertNativeForTransitionHeavyStages(session: SparkSession) + extends Rule[SparkPlan] + with Logging { + + private lazy val enabled = CometConf.COMET_EXEC_TRANSITION_REVERT_ENABLED.get() + private lazy val maxTransitions = CometConf.COMET_EXEC_TRANSITION_REVERT_MAX_TRANSITIONS.get() + + override def apply(plan: SparkPlan): SparkPlan = { + if (!enabled) return plan + + if (session.sessionState.conf.adaptiveExecutionEnabled) { + applyForAQE(plan) + } else { + applyForNonAQE(plan) + } + } + + private def applyForAQE(plan: SparkPlan): SparkPlan = { + plan match { + case _: BroadcastExchangeLike => plan + case exchange: ShuffleExchangeLike => + revertStageIfNeeded(exchange.child, exchange.supportsColumnar) + .map(reverted => exchange.withNewChildren(Seq(reverted))) + .getOrElse(plan) + case _ => + revertStageIfNeeded(plan, outputColumnar = false).getOrElse(plan) + } + } + + private def applyForNonAQE(plan: SparkPlan): SparkPlan = { + plan.transformUp { case exchange: ShuffleExchangeLike => + revertStageIfNeeded(exchange.child, exchange.supportsColumnar) + .map(reverted => exchange.withNewChildren(Seq(reverted))) + .getOrElse(exchange) + } + } + + /** + * Reverts the stage if C2R count exceeds threshold. Wraps in R2C if exchange needs columnar. + */ + private def revertStageIfNeeded( + stagePlan: SparkPlan, + outputColumnar: Boolean): Option[SparkPlan] = { + val transitionCount = countTransitions(stagePlan) + if (transitionCount <= maxTransitions) return None + + logInfo( + s"Reverting Comet native execution for stage with $transitionCount C2R transitions " + + s"(threshold: $maxTransitions).") + + val reverted = revertToSpark(stagePlan) + val result = if (outputColumnar && !reverted.supportsColumnar) { + RowToColumnarExec(reverted) + } else { + reverted + } + Some(result) + } + + /** Counts C2R transitions within this stage, stopping at stage boundaries. */ + private[rules] def countTransitions(plan: SparkPlan): Int = { + var count = 0 + def visit(node: SparkPlan): Unit = node match { + case _: QueryStageExec | _: ShuffleExchangeLike => () + case _: ColumnarToRowTransition => + count += 1 + node.children.foreach(visit) + case _ => + node.children.foreach(visit) + } + visit(plan) + count + } + + // Three passes: + // 1. Strip existing transitions (they assert child.supportsColumnar in constructors) + // 2. Revert Comet operators to row-based Spark equivalents + // 3. Re-insert ColumnarToRowExec where a columnar child feeds a row-based parent + // (e.g. QueryStageExec from a prior CometShuffleExchangeExec stage) + private[rules] def revertToSpark(plan: SparkPlan): SparkPlan = { + val stripped = plan.transformDown { + case CometNativeColumnarToRowExec(child) => child + case CometColumnarToRowExec(child) => child + case ColumnarToRowExec(child) => child + case sparkToColumnar: CometSparkToColumnarExec => sparkToColumnar.child + case RowToColumnarExec(child) => child + } + val reverted = stripped.transformUp { + case cometShuffle: CometShuffleExchangeExec => + cometShuffle.originalPlan.withNewChildren(Seq(cometShuffle.child)) + case cometExec: CometExec => + if (cometExec.originalPlan.children.size == cometExec.children.size) { + cometExec.originalPlan.withNewChildren(cometExec.children) + } else { Review Comment: Added a warnign ########## spark/src/main/scala/org/apache/comet/CometConf.scala: ########## @@ -442,6 +442,35 @@ object CometConf extends ShimCometConf { .booleanConf .createWithDefault(true) + val COMET_EXEC_TRANSITION_REVERT_ENABLED: ConfigEntry[Boolean] = + conf(s"$COMET_EXEC_CONFIG_PREFIX.transitionRevert.enabled") + .category(CATEGORY_EXEC) + .doc( + "When enabled, Comet reverts a query stage to Spark row-based execution if the number " + + "of columnar-to-row and row-to-columnar transition pairs exceeds the configured " + + "threshold. This avoids the overhead of repeated format conversions in stages where " + + "many operators fall back to row-based execution.") + .booleanConf + .createWithDefault(true) + + val COMET_EXEC_TRANSITION_REVERT_MAX_TRANSITIONS: ConfigEntry[Int] = + conf(s"$COMET_EXEC_CONFIG_PREFIX.transitionRevert.maxTransitions") + .category(CATEGORY_EXEC) + .doc( + "The maximum number of columnar-to-row (C2R) transitions allowed in a single query " + + "stage before Comet reverts the entire stage to Spark row-based execution. When " + + "columnar shuffle is enabled, each C2R has a corresponding row-to-columnar (R2C) " + + "conversion to feed back into the columnar shuffle, so the count reflects full " + + "round-trips. Minimum value is 2 because reverting a stage that feeds a columnar " + + "shuffle still requires at least one R2C at the shuffle boundary. " + + "Only effective when spark.comet.exec.transitionRevert.enabled is true.") + .intConf + .checkValue( + _ >= 2, + "Must be >= 2. A reverted stage still requires at least one " + + "R2C at the columnar shuffle boundary.") + .createWithDefault(2) Review Comment: I'd like to keep the threshold at 2 eventually since more than 2 transitions means significant overhead. But for now I've bumped it to 5 for CI to pass. Once we've reviewed the logic , we can iterate on the default and fix test failures than came with it?. ########## spark/src/main/scala/org/apache/comet/rules/RevertNativeForTransitionHeavyStages.scala: ########## @@ -0,0 +1,147 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +package org.apache.comet.rules + +import org.apache.spark.internal.Logging +import org.apache.spark.sql.SparkSession +import org.apache.spark.sql.catalyst.rules.Rule +import org.apache.spark.sql.comet.{CometColumnarToRowExec, CometExec, CometNativeColumnarToRowExec, CometSparkToColumnarExec} +import org.apache.spark.sql.comet.execution.shuffle.CometShuffleExchangeExec +import org.apache.spark.sql.execution.{ColumnarToRowExec, ColumnarToRowTransition, RowToColumnarExec, SparkPlan} +import org.apache.spark.sql.execution.adaptive.QueryStageExec +import org.apache.spark.sql.execution.exchange.{BroadcastExchangeLike, ShuffleExchangeLike} + +import org.apache.comet.CometConf + +/** + * Reverts a query stage to Spark row-based execution when it has too many columnar-to-row (C2R) + * transitions. Each C2R indicates Comet could not keep execution columnar and had to fall back. + * With columnar shuffle enabled, each C2R implies a corresponding R2C round-trip. + */ +case class RevertNativeForTransitionHeavyStages(session: SparkSession) + extends Rule[SparkPlan] + with Logging { + + private lazy val enabled = CometConf.COMET_EXEC_TRANSITION_REVERT_ENABLED.get() + private lazy val maxTransitions = CometConf.COMET_EXEC_TRANSITION_REVERT_MAX_TRANSITIONS.get() + + override def apply(plan: SparkPlan): SparkPlan = { + if (!enabled) return plan + + if (session.sessionState.conf.adaptiveExecutionEnabled) { + applyForAQE(plan) + } else { + applyForNonAQE(plan) + } + } + + private def applyForAQE(plan: SparkPlan): SparkPlan = { + plan match { + case _: BroadcastExchangeLike => plan + case exchange: ShuffleExchangeLike => + revertStageIfNeeded(exchange.child, exchange.supportsColumnar) + .map(reverted => exchange.withNewChildren(Seq(reverted))) + .getOrElse(plan) + case _ => + revertStageIfNeeded(plan, outputColumnar = false).getOrElse(plan) + } + } + + private def applyForNonAQE(plan: SparkPlan): SparkPlan = { + plan.transformUp { case exchange: ShuffleExchangeLike => + revertStageIfNeeded(exchange.child, exchange.supportsColumnar) + .map(reverted => exchange.withNewChildren(Seq(reverted))) + .getOrElse(exchange) + } + } + + /** + * Reverts the stage if C2R count exceeds threshold. Wraps in R2C if exchange needs columnar. + */ + private def revertStageIfNeeded( + stagePlan: SparkPlan, + outputColumnar: Boolean): Option[SparkPlan] = { + val transitionCount = countTransitions(stagePlan) + if (transitionCount <= maxTransitions) return None + + logInfo( + s"Reverting Comet native execution for stage with $transitionCount C2R transitions " + + s"(threshold: $maxTransitions).") + + val reverted = revertToSpark(stagePlan) + val result = if (outputColumnar && !reverted.supportsColumnar) { + RowToColumnarExec(reverted) + } else { + reverted + } + Some(result) + } + + /** Counts C2R transitions within this stage, stopping at stage boundaries. */ + private[rules] def countTransitions(plan: SparkPlan): Int = { + var count = 0 + def visit(node: SparkPlan): Unit = node match { + case _: QueryStageExec | _: ShuffleExchangeLike => () + case _: ColumnarToRowTransition => + count += 1 + node.children.foreach(visit) + case _ => + node.children.foreach(visit) + } + visit(plan) + count + } + + // Three passes: + // 1. Strip existing transitions (they assert child.supportsColumnar in constructors) + // 2. Revert Comet operators to row-based Spark equivalents + // 3. Re-insert ColumnarToRowExec where a columnar child feeds a row-based parent + // (e.g. QueryStageExec from a prior CometShuffleExchangeExec stage) + private[rules] def revertToSpark(plan: SparkPlan): SparkPlan = { + val stripped = plan.transformDown { + case CometNativeColumnarToRowExec(child) => child + case CometColumnarToRowExec(child) => child + case ColumnarToRowExec(child) => child + case sparkToColumnar: CometSparkToColumnarExec => sparkToColumnar.child + case RowToColumnarExec(child) => child + } + val reverted = stripped.transformUp { + case cometShuffle: CometShuffleExchangeExec => Review Comment: In AQE this is already handled — the broadcast exchange is wrapped in `BroadcastQueryStageExec` (which extends `QueryStageExec`), and `countTransitions` stops at `QueryStageExec`. For non-AQE, I've added `BroadcastExchangeLike` to the stop condition in countTransitions to treat it as an execution boundary.(as broadcast runs as a separate job independentof the parent stage). ########## spark/src/main/scala/org/apache/comet/rules/RevertNativeForTransitionHeavyStages.scala: ########## @@ -0,0 +1,147 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +package org.apache.comet.rules + +import org.apache.spark.internal.Logging +import org.apache.spark.sql.SparkSession +import org.apache.spark.sql.catalyst.rules.Rule +import org.apache.spark.sql.comet.{CometColumnarToRowExec, CometExec, CometNativeColumnarToRowExec, CometSparkToColumnarExec} +import org.apache.spark.sql.comet.execution.shuffle.CometShuffleExchangeExec +import org.apache.spark.sql.execution.{ColumnarToRowExec, ColumnarToRowTransition, RowToColumnarExec, SparkPlan} +import org.apache.spark.sql.execution.adaptive.QueryStageExec +import org.apache.spark.sql.execution.exchange.{BroadcastExchangeLike, ShuffleExchangeLike} + +import org.apache.comet.CometConf + +/** + * Reverts a query stage to Spark row-based execution when it has too many columnar-to-row (C2R) + * transitions. Each C2R indicates Comet could not keep execution columnar and had to fall back. + * With columnar shuffle enabled, each C2R implies a corresponding R2C round-trip. + */ +case class RevertNativeForTransitionHeavyStages(session: SparkSession) + extends Rule[SparkPlan] + with Logging { + + private lazy val enabled = CometConf.COMET_EXEC_TRANSITION_REVERT_ENABLED.get() + private lazy val maxTransitions = CometConf.COMET_EXEC_TRANSITION_REVERT_MAX_TRANSITIONS.get() + + override def apply(plan: SparkPlan): SparkPlan = { + if (!enabled) return plan + + if (session.sessionState.conf.adaptiveExecutionEnabled) { + applyForAQE(plan) + } else { + applyForNonAQE(plan) + } + } + + private def applyForAQE(plan: SparkPlan): SparkPlan = { + plan match { + case _: BroadcastExchangeLike => plan + case exchange: ShuffleExchangeLike => + revertStageIfNeeded(exchange.child, exchange.supportsColumnar) + .map(reverted => exchange.withNewChildren(Seq(reverted))) + .getOrElse(plan) + case _ => + revertStageIfNeeded(plan, outputColumnar = false).getOrElse(plan) + } + } + + private def applyForNonAQE(plan: SparkPlan): SparkPlan = { + plan.transformUp { case exchange: ShuffleExchangeLike => + revertStageIfNeeded(exchange.child, exchange.supportsColumnar) + .map(reverted => exchange.withNewChildren(Seq(reverted))) + .getOrElse(exchange) Review Comment: Added ########## spark/src/main/scala/org/apache/comet/rules/RevertNativeForTransitionHeavyStages.scala: ########## @@ -0,0 +1,147 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +package org.apache.comet.rules + +import org.apache.spark.internal.Logging +import org.apache.spark.sql.SparkSession +import org.apache.spark.sql.catalyst.rules.Rule +import org.apache.spark.sql.comet.{CometColumnarToRowExec, CometExec, CometNativeColumnarToRowExec, CometSparkToColumnarExec} +import org.apache.spark.sql.comet.execution.shuffle.CometShuffleExchangeExec +import org.apache.spark.sql.execution.{ColumnarToRowExec, ColumnarToRowTransition, RowToColumnarExec, SparkPlan} +import org.apache.spark.sql.execution.adaptive.QueryStageExec +import org.apache.spark.sql.execution.exchange.{BroadcastExchangeLike, ShuffleExchangeLike} + +import org.apache.comet.CometConf + +/** + * Reverts a query stage to Spark row-based execution when it has too many columnar-to-row (C2R) + * transitions. Each C2R indicates Comet could not keep execution columnar and had to fall back. + * With columnar shuffle enabled, each C2R implies a corresponding R2C round-trip. + */ +case class RevertNativeForTransitionHeavyStages(session: SparkSession) + extends Rule[SparkPlan] + with Logging { + + private lazy val enabled = CometConf.COMET_EXEC_TRANSITION_REVERT_ENABLED.get() + private lazy val maxTransitions = CometConf.COMET_EXEC_TRANSITION_REVERT_MAX_TRANSITIONS.get() + + override def apply(plan: SparkPlan): SparkPlan = { + if (!enabled) return plan + + if (session.sessionState.conf.adaptiveExecutionEnabled) { + applyForAQE(plan) + } else { + applyForNonAQE(plan) + } + } + + private def applyForAQE(plan: SparkPlan): SparkPlan = { + plan match { + case _: BroadcastExchangeLike => plan + case exchange: ShuffleExchangeLike => + revertStageIfNeeded(exchange.child, exchange.supportsColumnar) + .map(reverted => exchange.withNewChildren(Seq(reverted))) + .getOrElse(plan) + case _ => + revertStageIfNeeded(plan, outputColumnar = false).getOrElse(plan) + } + } + + private def applyForNonAQE(plan: SparkPlan): SparkPlan = { + plan.transformUp { case exchange: ShuffleExchangeLike => + revertStageIfNeeded(exchange.child, exchange.supportsColumnar) + .map(reverted => exchange.withNewChildren(Seq(reverted))) + .getOrElse(exchange) + } + } + + /** + * Reverts the stage if C2R count exceeds threshold. Wraps in R2C if exchange needs columnar. + */ + private def revertStageIfNeeded( + stagePlan: SparkPlan, + outputColumnar: Boolean): Option[SparkPlan] = { + val transitionCount = countTransitions(stagePlan) + if (transitionCount <= maxTransitions) return None + + logInfo( + s"Reverting Comet native execution for stage with $transitionCount C2R transitions " + + s"(threshold: $maxTransitions).") + + val reverted = revertToSpark(stagePlan) + val result = if (outputColumnar && !reverted.supportsColumnar) { + RowToColumnarExec(reverted) + } else { + reverted + } + Some(result) + } + + /** Counts C2R transitions within this stage, stopping at stage boundaries. */ + private[rules] def countTransitions(plan: SparkPlan): Int = { + var count = 0 + def visit(node: SparkPlan): Unit = node match { + case _: QueryStageExec | _: ShuffleExchangeLike => () + case _: ColumnarToRowTransition => + count += 1 + node.children.foreach(visit) + case _ => + node.children.foreach(visit) + } + visit(plan) + count + } + + // Three passes: + // 1. Strip existing transitions (they assert child.supportsColumnar in constructors) + // 2. Revert Comet operators to row-based Spark equivalents + // 3. Re-insert ColumnarToRowExec where a columnar child feeds a row-based parent + // (e.g. QueryStageExec from a prior CometShuffleExchangeExec stage) + private[rules] def revertToSpark(plan: SparkPlan): SparkPlan = { + val stripped = plan.transformDown { + case CometNativeColumnarToRowExec(child) => child + case CometColumnarToRowExec(child) => child + case ColumnarToRowExec(child) => child + case sparkToColumnar: CometSparkToColumnarExec => sparkToColumnar.child + case RowToColumnarExec(child) => child + } + val reverted = stripped.transformUp { + case cometShuffle: CometShuffleExchangeExec => + cometShuffle.originalPlan.withNewChildren(Seq(cometShuffle.child)) + case cometExec: CometExec => + if (cometExec.originalPlan.children.size == cometExec.children.size) { + cometExec.originalPlan.withNewChildren(cometExec.children) + } else { + cometExec.originalPlan + } + } + insertTransitions(reverted) + } + + private def insertTransitions(plan: SparkPlan): SparkPlan = { + plan.transformUp { + case node if !node.isInstanceOf[QueryStageExec] && !node.supportsColumnar => + val newChildren = node.children.map { child => + if (child.supportsColumnar) ColumnarToRowExec(child) else child Review Comment: After `revertToSpark`, all CometExec nodes are replaced with their row-based operator. The only columnar nodes remaining would be QueryStageExec leaves (inputs from prior stages). I think we will have only columnar children feeding row-based parents. May be i am missing the scenario, an example would help. ########## spark/src/main/scala/org/apache/comet/rules/RevertNativeForTransitionHeavyStages.scala: ########## @@ -0,0 +1,147 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +package org.apache.comet.rules + +import org.apache.spark.internal.Logging +import org.apache.spark.sql.SparkSession +import org.apache.spark.sql.catalyst.rules.Rule +import org.apache.spark.sql.comet.{CometColumnarToRowExec, CometExec, CometNativeColumnarToRowExec, CometSparkToColumnarExec} +import org.apache.spark.sql.comet.execution.shuffle.CometShuffleExchangeExec +import org.apache.spark.sql.execution.{ColumnarToRowExec, ColumnarToRowTransition, RowToColumnarExec, SparkPlan} +import org.apache.spark.sql.execution.adaptive.QueryStageExec +import org.apache.spark.sql.execution.exchange.{BroadcastExchangeLike, ShuffleExchangeLike} + +import org.apache.comet.CometConf + +/** + * Reverts a query stage to Spark row-based execution when it has too many columnar-to-row (C2R) + * transitions. Each C2R indicates Comet could not keep execution columnar and had to fall back. + * With columnar shuffle enabled, each C2R implies a corresponding R2C round-trip. + */ +case class RevertNativeForTransitionHeavyStages(session: SparkSession) + extends Rule[SparkPlan] + with Logging { + + private lazy val enabled = CometConf.COMET_EXEC_TRANSITION_REVERT_ENABLED.get() + private lazy val maxTransitions = CometConf.COMET_EXEC_TRANSITION_REVERT_MAX_TRANSITIONS.get() + + override def apply(plan: SparkPlan): SparkPlan = { + if (!enabled) return plan + + if (session.sessionState.conf.adaptiveExecutionEnabled) { + applyForAQE(plan) + } else { + applyForNonAQE(plan) + } + } + + private def applyForAQE(plan: SparkPlan): SparkPlan = { + plan match { + case _: BroadcastExchangeLike => plan + case exchange: ShuffleExchangeLike => + revertStageIfNeeded(exchange.child, exchange.supportsColumnar) + .map(reverted => exchange.withNewChildren(Seq(reverted))) + .getOrElse(plan) + case _ => + revertStageIfNeeded(plan, outputColumnar = false).getOrElse(plan) + } + } + + private def applyForNonAQE(plan: SparkPlan): SparkPlan = { + plan.transformUp { case exchange: ShuffleExchangeLike => + revertStageIfNeeded(exchange.child, exchange.supportsColumnar) + .map(reverted => exchange.withNewChildren(Seq(reverted))) + .getOrElse(exchange) + } + } + + /** + * Reverts the stage if C2R count exceeds threshold. Wraps in R2C if exchange needs columnar. + */ + private def revertStageIfNeeded( + stagePlan: SparkPlan, + outputColumnar: Boolean): Option[SparkPlan] = { + val transitionCount = countTransitions(stagePlan) + if (transitionCount <= maxTransitions) return None + + logInfo( + s"Reverting Comet native execution for stage with $transitionCount C2R transitions " + + s"(threshold: $maxTransitions).") + + val reverted = revertToSpark(stagePlan) + val result = if (outputColumnar && !reverted.supportsColumnar) { + RowToColumnarExec(reverted) + } else { + reverted + } + Some(result) + } + + /** Counts C2R transitions within this stage, stopping at stage boundaries. */ + private[rules] def countTransitions(plan: SparkPlan): Int = { + var count = 0 + def visit(node: SparkPlan): Unit = node match { + case _: QueryStageExec | _: ShuffleExchangeLike => () + case _: ColumnarToRowTransition => + count += 1 + node.children.foreach(visit) + case _ => + node.children.foreach(visit) + } + visit(plan) + count + } + + // Three passes: + // 1. Strip existing transitions (they assert child.supportsColumnar in constructors) + // 2. Revert Comet operators to row-based Spark equivalents + // 3. Re-insert ColumnarToRowExec where a columnar child feeds a row-based parent + // (e.g. QueryStageExec from a prior CometShuffleExchangeExec stage) + private[rules] def revertToSpark(plan: SparkPlan): SparkPlan = { + val stripped = plan.transformDown { + case CometNativeColumnarToRowExec(child) => child + case CometColumnarToRowExec(child) => child + case ColumnarToRowExec(child) => child + case sparkToColumnar: CometSparkToColumnarExec => sparkToColumnar.child + case RowToColumnarExec(child) => child + } + val reverted = stripped.transformUp { + case cometShuffle: CometShuffleExchangeExec => + cometShuffle.originalPlan.withNewChildren(Seq(cometShuffle.child)) + case cometExec: CometExec => + if (cometExec.originalPlan.children.size == cometExec.children.size) { + cometExec.originalPlan.withNewChildren(cometExec.children) + } else { + cometExec.originalPlan + } + } + insertTransitions(reverted) + } + + private def insertTransitions(plan: SparkPlan): SparkPlan = { + plan.transformUp { + case node if !node.isInstanceOf[QueryStageExec] && !node.supportsColumnar => + val newChildren = node.children.map { child => + if (child.supportsColumnar) ColumnarToRowExec(child) else child + } + if (newChildren != node.children) node.withNewChildren(newChildren) else node + } + } +} Review Comment: Unrelated? ########## spark/src/test/scala/org/apache/comet/rules/RevertNativeForTransitionHeavyStagesSuite.scala: ########## @@ -0,0 +1,277 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +package org.apache.comet.rules + +import org.apache.spark.sql.CometTestBase +import org.apache.spark.sql.comet._ +import org.apache.spark.sql.comet.execution.shuffle.CometShuffleExchangeExec +import org.apache.spark.sql.execution._ +import org.apache.spark.sql.execution.exchange.ShuffleExchangeExec + +import org.apache.comet.CometConf + +class RevertNativeForTransitionHeavyStagesSuite extends CometTestBase { + + private def createSparkPlan(sql: String): SparkPlan = { + var plan: SparkPlan = null + withSQLConf(CometConf.COMET_ENABLED.key -> "false") { + plan = spark.sql(sql).queryExecution.executedPlan + } + stripAQEPlan(plan) + } + + private def applyCometExecRule(plan: SparkPlan): SparkPlan = { + CometExecRule(spark).apply(plan) + } + + private def applyFullColumnarPipeline(plan: SparkPlan): SparkPlan = { + val cometPlan = CometScanRule(spark).apply(plan) + val execPlan = CometExecRule(spark).apply(cometPlan) + val withTransitions = ApplyColumnarRulesAndInsertTransitions(Seq.empty, false).apply(execPlan) + EliminateRedundantTransitions(spark).apply(withTransitions) + } + + private def countCometExecs(plan: SparkPlan): Int = { + plan.collect { case _: CometExec => true }.size + } + + private def countC2RNodes(plan: SparkPlan): Int = { + plan.collect { case _: ColumnarToRowTransition => true }.size + } + + test("rule is a no-op when disabled") { + withSQLConf( + CometConf.COMET_ENABLED.key -> "true", + CometConf.COMET_EXEC_ENABLED.key -> "true", + CometConf.COMET_EXEC_TRANSITION_REVERT_ENABLED.key -> "false") { + val rule = RevertNativeForTransitionHeavyStages(spark) + val sparkPlan = createSparkPlan("SELECT 1") + val cometPlan = applyCometExecRule(sparkPlan) + val result = rule.apply(cometPlan) + assert(result eq cometPlan, "Rule should be a no-op when disabled") + } + } + + test("rule does not revert plan below threshold") { + withSQLConf( + CometConf.COMET_ENABLED.key -> "true", + CometConf.COMET_EXEC_ENABLED.key -> "true", + CometConf.COMET_EXEC_TRANSITION_REVERT_ENABLED.key -> "true", + CometConf.COMET_EXEC_TRANSITION_REVERT_MAX_TRANSITIONS.key -> "10") { + withTempView("test_data") { + spark.range(10).toDF("id").createOrReplaceTempView("test_data") + val sparkPlan = + createSparkPlan("SELECT id, id * 2 as doubled FROM test_data WHERE id > 5") + val cometPlan = applyCometExecRule(sparkPlan) + + val rule = RevertNativeForTransitionHeavyStages(spark) + val result = rule.apply(cometPlan) + assert(result eq cometPlan, "Plan should be unchanged when below threshold") + } + } + } + + test("countTransitions counts non-root C2R correctly") { + withSQLConf( + CometConf.COMET_ENABLED.key -> "true", + CometConf.COMET_EXEC_ENABLED.key -> "true") { + val rule = RevertNativeForTransitionHeavyStages(spark) + + withTempView("test_data") { + spark.range(10).toDF("id").createOrReplaceTempView("test_data") + val sparkPlan = createSparkPlan("SELECT id FROM test_data") + val cometPlan = applyFullColumnarPipeline(sparkPlan) + + val count = rule.countTransitions(cometPlan) + // A simple scan+project plan should have 0 or 1 transitions + assert(count >= 0, s"Transition count should be non-negative, got $count") + } + } + } + + test("countTransitions counts all C2R nodes including root") { + withSQLConf( + CometConf.COMET_ENABLED.key -> "true", + CometConf.COMET_EXEC_ENABLED.key -> "true") { + val rule = RevertNativeForTransitionHeavyStages(spark) + + withTempView("test_data") { + spark.range(10).toDF("id").createOrReplaceTempView("test_data") + val sparkPlan = createSparkPlan("SELECT id FROM test_data") + val cometPlan = applyCometExecRule(sparkPlan) + + // Wrap in a ColumnarToRow (simulating a terminal output) + val planWithRootC2R = ColumnarToRowExec(cometPlan) + val count = rule.countTransitions(planWithRootC2R) + assert(count == 1, s"Should count the C2R node, got $count") + } + } + } + + test("revertToSpark removes CometExec operators") { + withSQLConf( + CometConf.COMET_ENABLED.key -> "true", + CometConf.COMET_EXEC_ENABLED.key -> "true", + CometConf.COMET_EXEC_LOCAL_TABLE_SCAN_ENABLED.key -> "true") { + + withTempView("test_data") { + spark.range(10).toDF("id").createOrReplaceTempView("test_data") + val sparkPlan = + createSparkPlan("SELECT id, id * 2 as doubled FROM test_data WHERE id > 5") + val cometPlan = applyCometExecRule(sparkPlan) + + assert(countCometExecs(cometPlan) > 0, "Should have CometExec nodes before revert") + + val rule = RevertNativeForTransitionHeavyStages(spark) + val reverted = rule.revertToSpark(cometPlan) + + assert( + countCometExecs(reverted) == 0, + s"Should have no CometExec nodes after revert, plan:\n${reverted.treeString}") + } + } + } + + test("revertToSpark preserves plan structure") { + withSQLConf( + CometConf.COMET_ENABLED.key -> "true", + CometConf.COMET_EXEC_ENABLED.key -> "true", + CometConf.COMET_EXEC_LOCAL_TABLE_SCAN_ENABLED.key -> "true") { + + withTempView("test_data") { + spark.range(10).toDF("id").createOrReplaceTempView("test_data") + val sparkPlan = + createSparkPlan("SELECT id, id * 2 as doubled FROM test_data WHERE id > 5") + val cometPlan = applyCometExecRule(sparkPlan) + val rule = RevertNativeForTransitionHeavyStages(spark) + val reverted = rule.revertToSpark(cometPlan) + + // Reverted plan should have same output schema + assert( + reverted.output.map(_.name) == cometPlan.output.map(_.name), + "Output schema should be preserved after revert") + } + } + } + + test("revertToSpark removes all Comet operators from a plan with transitions") { + withSQLConf( + CometConf.COMET_ENABLED.key -> "true", + CometConf.COMET_EXEC_ENABLED.key -> "true", + CometConf.COMET_EXEC_LOCAL_TABLE_SCAN_ENABLED.key -> "true", + CometConf.COMET_EXEC_TRANSITION_REVERT_ENABLED.key -> "true") { + + withTempView("test_data") { + spark.range(10).toDF("id").createOrReplaceTempView("test_data") + val sparkPlan = + createSparkPlan("SELECT id, id * 2 as doubled FROM test_data WHERE id > 5") + val cometPlan = applyFullColumnarPipeline(sparkPlan) + + val rule = RevertNativeForTransitionHeavyStages(spark) + val result = rule.revertToSpark(cometPlan) + assert( + countCometExecs(result) == 0, + s"All CometExec should be reverted. Plan:\n${result.treeString}") + } + } + } + + test("CometShuffleExchangeExec is reverted by revertToSpark") { + withSQLConf( + CometConf.COMET_ENABLED.key -> "true", + CometConf.COMET_EXEC_ENABLED.key -> "true", + CometConf.COMET_EXEC_SHUFFLE_ENABLED.key -> "true", + "spark.sql.adaptive.enabled" -> "false") { + + withTempView("test_data") { + spark.range(10).toDF("id").createOrReplaceTempView("test_data") + val sparkPlan = createSparkPlan("SELECT id FROM test_data DISTRIBUTE BY id") + val cometPlan = applyCometExecRule(sparkPlan) + + val cometShuffles = cometPlan.collect { case s: CometShuffleExchangeExec => s } + if (cometShuffles.nonEmpty) { + val rule = RevertNativeForTransitionHeavyStages(spark) + val reverted = rule.revertToSpark(cometPlan) + val remainingCometShuffles = reverted.collect { case s: CometShuffleExchangeExec => + s + } + assert( + remainingCometShuffles.isEmpty, + "CometShuffleExchangeExec should be reverted to ShuffleExchangeExec") + val sparkShuffles = reverted.collect { case s: ShuffleExchangeExec => s } + assert(sparkShuffles.nonEmpty, "Should have ShuffleExchangeExec after revert") + } + } + } + } + + test("non-AQE path applies rule per-stage via transformUp") { + withSQLConf( + CometConf.COMET_ENABLED.key -> "true", + CometConf.COMET_EXEC_ENABLED.key -> "true", + CometConf.COMET_EXEC_SHUFFLE_ENABLED.key -> "true", + CometConf.COMET_EXEC_TRANSITION_REVERT_ENABLED.key -> "true", + CometConf.COMET_EXEC_TRANSITION_REVERT_MAX_TRANSITIONS.key -> "10", + "spark.sql.adaptive.enabled" -> "false") { + + withTempView("test_data") { + spark + .range(10) + .selectExpr("id", "id % 3 as grp") + .createOrReplaceTempView("test_data") + val sparkPlan = createSparkPlan("SELECT grp, count(*) FROM test_data GROUP BY grp") + val cometPlan = applyCometExecRule(sparkPlan) + + // With high threshold, the non-AQE path should not revert anything + val rule = RevertNativeForTransitionHeavyStages(spark) + val result = rule.apply(cometPlan) + assert(result eq cometPlan, "Non-AQE path should not revert when below threshold") + } + } + } + + test("default threshold of 2 allows stages with up to 2 transition pairs") { + withSQLConf( + CometConf.COMET_ENABLED.key -> "true", + CometConf.COMET_EXEC_ENABLED.key -> "true", + CometConf.COMET_EXEC_TRANSITION_REVERT_ENABLED.key -> "true", + CometConf.COMET_EXEC_TRANSITION_REVERT_MAX_TRANSITIONS.key -> "2") { + val rule = RevertNativeForTransitionHeavyStages(spark) + + withTempView("test_data") { + spark.range(10).toDF("id").createOrReplaceTempView("test_data") + val sparkPlan = createSparkPlan("SELECT id FROM test_data") + val cometPlan = applyFullColumnarPipeline(sparkPlan) + + val pairs = rule.countTransitions(cometPlan) + val result = rule.apply(cometPlan) + if (pairs <= 2) { + assert( + result eq cometPlan, + s"Plan with $pairs pairs should NOT be reverted at threshold 2") + } else { + assert( + countCometExecs(result) == 0, + s"Plan with $pairs pairs should be reverted at threshold 2") + } + } + } + } +} Review Comment: I disabled the project operator to guarantee transitions Do you think we still need a test with a naturally fallback (unsupported expression may be UDF), or is the current approach sufficient? -- This is an automated message from the Apache Git Service. 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