Skip to content
Open
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Original file line number Diff line number Diff line change
Expand Up @@ -577,6 +577,7 @@ public enum LogKeys implements LogKey {
OUTPUT_BUFFER,
OVERHEAD_MEMORY_SIZE,
PAGE_SIZE,
PARENT_STAGE,
PARENT_STAGES,
PARSE_MODE,
PARTITIONED_FILE_READER,
Expand Down Expand Up @@ -792,6 +793,7 @@ public enum LogKeys implements LogKey {
STREAMING_DATA_SOURCE_NAME,
STREAMING_OFFSETS_END,
STREAMING_OFFSETS_START,
STREAMING_QUERY_ID,

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

QUERY_ID already exists and is what StructuredStreamingIdAwareSchedulerLogging uses to log streaming query IDs. Adding STREAMING_QUERY_ID creates a parallel key for the same concept. Suggest dropping this addition and using LogKeys.QUERY_ID at all the callsites, or update the callsites in StructuredStreamingIdAwareSchedulerLogging.

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

A query id and streaming query id are typically not the same. query id for a batch query is simply a transient id for a batch. The streaming query id is persistent for the entirety of the streaming query execution.

I would keep it here and fix it in StructuredStreamingIdAwareSchedulerLogging

STREAMING_QUERY_PROGRESS,
STREAMING_SOURCE,
STREAMING_TABLE,
Expand Down
6 changes: 6 additions & 0 deletions common/utils/src/main/resources/error/error-conditions.json
Original file line number Diff line number Diff line change
Expand Up @@ -890,6 +890,12 @@
],
"sqlState" : "0A000"
},
"CONCURRENT_SCHEDULER_INSUFFICIENT_SLOT" : {
"message" : [
"The minimum number of free slots required in the cluster is <numTasks>, however, the cluster has only <numSlots> slots free. Query will stall or fail. Increase cluster size to proceed."
],
"sqlState" : "53000"
},
"CONCURRENT_STREAM_LOG_UPDATE" : {
"message" : [
"Concurrent update to the log. Multiple streaming jobs detected for <batchId>.",
Expand Down
6 changes: 5 additions & 1 deletion core/src/main/scala/org/apache/spark/SparkContext.scala
Original file line number Diff line number Diff line change
Expand Up @@ -600,7 +600,11 @@ class SparkContext(config: SparkConf) extends Logging {
val (sched, ts) = SparkContext.createTaskScheduler(this, master)
_schedulerBackend = sched
_taskScheduler = ts
_dagScheduler = new DAGScheduler(this)
_dagScheduler = conf.get(DAG_SCHEDULER_TYPE) match {
case "ConcurrentStageDAGScheduler" =>
new ConcurrentStageDAGScheduler(this)
case _ => new DAGScheduler(this)
}
_heartbeatReceiver.ask[Boolean](TaskSchedulerIsSet)

if (_conf.get(EXECUTOR_ALLOW_SYNC_LOG_LEVEL)) {
Expand Down
20 changes: 20 additions & 0 deletions core/src/main/scala/org/apache/spark/internal/config/package.scala
Original file line number Diff line number Diff line change
Expand Up @@ -2396,6 +2396,26 @@ package object config {
.booleanConf
.createWithDefault(true)

private[spark] val STREAMING_REALTIME_MODE_SLOTS_CHECK_DISABLED =

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Normally we would use _ENABLED instead of _DISABLED, to avoid double-negative.

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The intent is that slot checking is enabled by default and you should disable it in extra ordinary circumstances. That is why it was named this way. If you don't feel strongly about this I would rather keep it as it is.

ConfigBuilder("spark.scheduler.realtimeModeSlotsCheck.disabled")
.internal()
.doc("For query running in real time mode, disable the check if the number of slots" +
" required by all concurrent stages is available before submit the query" )
.withBindingPolicy(ConfigBindingPolicy.NOT_APPLICABLE)
.version("4.2.0")
.booleanConf
.createWithDefault(false)

private[spark] val DAG_SCHEDULER_TYPE =
ConfigBuilder("spark.scheduler.dagSchedulerType")
.internal()
.doc("The DAGScheduler implementation to use. Set to 'ConcurrentStageDAGScheduler' to " +
"enable real-time mode, which runs stages concurrently for low-latency streaming queries.")
.withBindingPolicy(ConfigBindingPolicy.NOT_APPLICABLE)
.version("4.2.0")
.stringConf
.createWithDefault("DAGScheduler")

private[spark] val STREAMING_ID_AWARE_SCHEDULER_LOGGING_QUERY_ID_LENGTH =
ConfigBuilder("spark.scheduler.streaming.idAwareLogging.queryIdLength")
.doc("Maximum number of characters of the streaming query ID to include " +
Expand Down
Original file line number Diff line number Diff line change
@@ -0,0 +1,320 @@
/*
* 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.spark.scheduler

import java.util.Properties

import scala.collection.mutable

import org.apache.spark.{MapOutputTrackerMaster, SparkContext, SparkEnv, SparkException, SparkRuntimeException, Success}
import org.apache.spark.internal.LogKeys
import org.apache.spark.internal.config.{SPECULATION_ENABLED, STREAMING_REALTIME_MODE_SLOTS_CHECK_DISABLED}
import org.apache.spark.resource.ResourceProfile
import org.apache.spark.storage.BlockManagerMaster
import org.apache.spark.util.Clock
import org.apache.spark.util.SystemClock

/**
* A [[DAGScheduler]] that runs all the stages in a job without waiting for its parents
* complete. This combined with streaming shuffle between the stages, allows for low latency
* execution of streaming queries in real-time mode.
*/
class ConcurrentStageDAGScheduler(
sc: SparkContext,
taskScheduler: TaskScheduler,
listenerBus: LiveListenerBus,
mapOutputTracker: MapOutputTrackerMaster,
blockManagerMaster: BlockManagerMaster,
env: SparkEnv,
clock: Clock = new SystemClock())
extends DAGScheduler(
sc, taskScheduler, listenerBus, mapOutputTracker, blockManagerMaster, env, clock) {

import ConcurrentStageDAGScheduler._

def this(sc: SparkContext, taskScheduler: TaskScheduler) = {
this(
sc,
taskScheduler,
sc.listenerBus,
sc.env.mapOutputTracker.asInstanceOf[MapOutputTrackerMaster],
sc.env.blockManager.master,
sc.env
)
}

def this(sc: SparkContext) = this(sc, sc.taskScheduler)

// This contains all the concurrent stages that are yet to be scheduled across all the jobs.
private[spark] val concurrentStages = new mutable.HashSet[Stage]

private[scheduler] case class DependentStageInfo(
parents: mutable.HashSet[Stage] = mutable.HashSet.empty,
delayedTaskCompletionEvents: mutable.ListBuffer[CompletionEvent] = mutable.ListBuffer.empty)

// This map holds parents of concurrently scheduled stages. When tasks for such a stage complete,
// and if any of the parents are still running, we delay processing of such events until parent
// stages are complete. We save these events in this map until then.
private[spark] val dependentStageMap = new mutable.HashMap[Stage, DependentStageInfo]

private def totalNumCoreForStage(stage: Stage): Int = {
val numTask = stage match {
case r: ResultStage => r.partitions.length
case m: ShuffleMapStage => m.numPartitions
}
val resourceProfile = sc.resourceProfileManager.resourceProfileFromId(stage.resourceProfileId)
val taskCpus = ResourceProfile.getTaskCpusOrDefaultForProfile(resourceProfile, sc.conf)
taskCpus * numTask
}

/**
* Hook invoked after the final stage is created. Registers stages reachable from
* the final stage as concurrent so they can be submitted in parallel.
*/
override def onFinalStageCreated(finalStage: Stage, properties: Properties): Unit = {

val queryBatchId = getStreamingBatchIdFromProperties(properties)

if (queryBatchId.nonEmpty && isConcurrentStagesEnabled(properties)) {
// Speculation is not supported with concurrent stages. Check both the per-job local
// property (for jobs that override the cluster default via setLocalProperty) and the
// SparkConf (the documented way to enable speculation cluster-wide).
if (properties.getProperty(SPECULATION_ENABLED.key) == "true" ||
sc.conf.get(SPECULATION_ENABLED)) {
throw new SparkException(
"Speculative execution is not supported with concurrent stages " +
s"(streaming query: $queryBatchId). Please disable ${SPECULATION_ENABLED.key} config."
)
}

logInfo(log"Concurrent stages is enabled for [query ${MDC(LogKeys.STREAMING_QUERY_ID,
queryBatchId.get.queryId)} batch ${MDC(LogKeys.BATCH_ID, queryBatchId.get.batchId)}]")

// Mark current stage and all its ancestors as concurrent.
// Collect into a local set first so a slot-check failure below does not leak partial
// state into concurrentStages.
val visitedStages = new mutable.HashSet[Stage]
var totalCoresNeeded = 0
def visit(stage: Stage): Unit = {
if (!visitedStages.contains(stage)) {
logInfo(log"Marking stage '${MDC(LogKeys.STAGE, stage)}' concurrent for [query ${MDC(
LogKeys.STREAMING_QUERY_ID, queryBatchId.get.queryId)} batch ${MDC(
LogKeys.BATCH_ID, queryBatchId.get.batchId)}]")
visitedStages += stage
totalCoresNeeded += totalNumCoreForStage(stage)
stage.parents.foreach(visit)
}
}
visit(finalStage)

if (!sc.conf.get(STREAMING_REALTIME_MODE_SLOTS_CHECK_DISABLED)) {
try {
val totalSlots = sc.schedulerBackend.defaultParallelism()
val coresInUse = runningStages.toArray.map(totalNumCoreForStage(_)).sum
if (totalSlots - coresInUse < totalCoresNeeded) {
throw new SparkRuntimeException(

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

When this throws, the stages added to concurrentStages above are leaked — handleJobSubmitted catches the exception and fails the job, but nothing ever clears those entries. A subsequent job whose stages share IDs (e.g. retries from the same RDDChain) would inherit them. Either clear concurrentStages of the stages just visited before throwing, or capture them in a local set and only commit to concurrentStages once the slot check passes.

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

fixed by accumulating into a local visitedStages set during the DAG walk and only committing to concurrentStages after the slot check passes

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Though the actual affect of this would likely be small since this would only occur on query failure.

errorClass = "CONCURRENT_SCHEDULER_INSUFFICIENT_SLOT",
messageParameters = Map(
"numSlots" -> (totalSlots - coresInUse).toString,
"numTasks" -> totalCoresNeeded.toString))
}
} catch {
case e: UnsupportedOperationException =>
logWarning(log"${MDC(LogKeys.ERROR, e)}. Skipping slot check for RTM.")
}
}

// Slot check passed (or was disabled). Commit the visited stages.
concurrentStages ++= visitedStages
} else {
super.onFinalStageCreated(finalStage, properties)
}
}

override def submitStage(stage: Stage): Unit = {
super.submitStage(stage)

if (!waitingStages.contains(stage) && concurrentStages.contains(stage)) {
// The current stage is not registered in waitingStages, which means it has
// no parents. This case we should remove it from concurrentStages since it is already
// running.
assert(runningStages.contains(stage), "stage should be running if not in waitingStages")
logInfo(log"Removing stage ${MDC(LogKeys.STAGE, stage)} from concurrentStages")
concurrentStages -= stage
}

// Find the stages that should be submitted concurrently with this stage.
waitingStages.intersect(concurrentStages).foreach { stage =>
logInfo(log"Submitting stage concurrently: ${MDC(LogKeys.STAGE, stage)}")
concurrentStages -= stage // Don't submit this stage concurrently for subsequent attempts.
stage.parents.foreach { parent =>
if (isRunningStage(parent)) {
logInfo(log"Updating dependent map for stage ${MDC(LogKeys.STAGE, stage)} with parent ${
MDC(LogKeys.PARENT_STAGE, parent)}")
dependentStageMap.getOrElseUpdate(stage, DependentStageInfo()).parents += parent
}
}
// Remove stage and its parents from concurrentStages
def removeFromConcurrentStages(stage: Stage): Unit = {
if (concurrentStages.contains(stage)) {
logInfo(log"Removing stage ${MDC(LogKeys.STAGE, stage)} from concurrentStages")
concurrentStages -= stage
}
stage.parents.foreach { parent =>
assert(!waitingStages.contains(parent), "Parent stage should not still be waiting")
removeFromConcurrentStages(parent)
}
}
removeFromConcurrentStages(stage)
submitConcurrentStage(stage)
}
}

/**
* Submits a child stage even while its parents are still running. Distinct from
* `submitStage` in that it bypasses the missing-parent check.
*/
private def submitConcurrentStage(stage: Stage): Unit = {
assert(waitingStages.contains(stage))
activeJobForStage(stage) match {
case Some(job) =>
waitingStages -= stage
submitMissingTasks(stage, job)
case None => // Not expected.
throw new IllegalStateException(s"No active job for stage $stage")
}
}

// This is overridden to check if the task completion event should be delayed because a
// parent stage still has running tasks. See comment for `dependentStageMap` for more details.
override private[scheduler] def handleTaskCompletion(event: CompletionEvent): Unit = {
val stageId = event.task.stageId
val taskId = event.taskInfo.taskId

getStage(stageId) match {
case Some(stage) if event.reason == Success && dependentStageMap.contains(stage) =>
val dependentStageInfo = dependentStageMap(stage)
logInfo(log"Delaying completion event for task ${MDC(LogKeys.TASK_ID, taskId)} in stage ${
MDC(LogKeys.STAGE, stage)}. Active parent(s): ${MDC(LogKeys.PARENT_STAGES,
dependentStageInfo.parents.mkString(", "))}")
dependentStageInfo.delayedTaskCompletionEvents += event

case _ => // Otherwise handle the event as usual.
super.handleTaskCompletion(event)
}
}

// This is overridden to handle any delayed task completion events for dependent stages.
override def markStageAsFinished(

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The dependentStageMap cleanup path only fires when a stage in the map is named as a parent via markStageAsFinished(parent). If a dependent stage itself aborts mid-job (e.g. its single allowed failure under maxTaskFailures=1), its own entry — including any buffered delayedTaskCompletionEvents — is never removed from dependentStageMap. With concurrent jobs sharing a long-lived scheduler instance, that's a slow leak across queries. Consider clearing the entry for stage itself inside markStageAsFinished (especially when errorMessage.isDefined).

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I will just remove the stage's own entry at the end of markStageAsFinished

stage: Stage,
errorMessage: Option[String] = None,
willRetry: Boolean = false): Unit = {

super.markStageAsFinished(stage, errorMessage, willRetry)

// If this is a parent of a stage in dependentStageMap, remove it from parents.
val dependentStages = dependentStageMap
.filter(_._2.parents.contains(stage))
.keys

dependentStages.foreach { dependent =>
if (errorMessage.isEmpty) {
assert(
isRunningStage(dependent),
s"Parent stages $stage's dependent stage $dependent should be running")
}
logInfo(log"Removing parent stage ${MDC(LogKeys.PARENT_STAGE, stage)} from dependent map " +
log"for stage ${MDC(LogKeys.STAGE, dependent)}")
dependentStageMap(dependent).parents -= stage
checkDependentStageTasks(dependent)
}

// Drop this stage's own entry from the map. On the success path
// `checkDependentStageTasks` (invoked when the stage's last parent finishes) has already
// removed the entry, so this is a no-op. On failure / cancellation / abort the entry,
// and any buffered completion events, would otherwise leak for the lifetime of the
// scheduler.
//
// `willRetry=true` paths (e.g. FetchFailed) also reach this cleanup. That is safe under
// concurrent scheduling because stage retries are not supported here: TaskSchedulerImpl
// pins `maxFailures=1` for concurrent TaskSets, and any failure restarts the streaming
// query from its checkpoint rather than retrying tasks against an in-flight streaming
// shuffle. With no retry to preserve state for, it's correct to drop the entry along
// with any buffered events.
dependentStageMap.remove(stage)
}

// Checks if the dependent stage's parents are all done. If all the parents are done,
// enqueues any saved task completion event (if any).
private def checkDependentStageTasks(stage: Stage): Unit = {
val dependentStageInfo = dependentStageMap.getOrElse(
stage, throw new IllegalStateException(s"Stage $stage is not in dependentStageMap")
)

if (dependentStageInfo.parents.isEmpty) {
val delayedEvents = dependentStageInfo.delayedTaskCompletionEvents
logInfo(log"All the parents are done for ${MDC(LogKeys.STAGE, stage)}. Removing it from " +
log"the map. It has ${MDC(LogKeys.NUM_EVENTS, delayedEvents.size.toLong)} " +
log"task completion events")
dependentStageMap -= stage
delayedEvents.foreach { event =>
logInfo(log"Posting delayed task ${MDC(LogKeys.TASK_ID, event.taskInfo.taskId)} " +
log"completion event for stage ${MDC(LogKeys.STAGE, stage)}")
eventProcessLoop.post(event)
}
}
}
}

object ConcurrentStageDAGScheduler {

val CONCURRENT_STAGES_ENABLED_PROPERTY: String = "streaming.concurrent.stages.enabled"

def isConcurrentStagesEnabled(properties: Properties): Boolean = {
properties != null &&
properties.getProperty(CONCURRENT_STAGES_ENABLED_PROPERTY) == "true"
}

/**
* Extracts the [[StreamingBatchId]] from the given properties if both the streaming
* query id and batch id are present.
*/
def getStreamingBatchIdFromProperties(properties: Properties): Option[StreamingBatchId] = {
if (properties == null) {
return None
}

val queryId = Option(properties.getProperty(
StructuredStreamingIdAwareSchedulerLogging.QUERY_ID_KEY))
val batchId = Option(properties.getProperty(
StructuredStreamingIdAwareSchedulerLogging.BATCH_ID_KEY))
if (queryId.nonEmpty && batchId.nonEmpty) {
Some(StreamingBatchId(queryId.get, batchId.get.toLong))
} else {
None
}
}
}

/**
* Case class to identify a batch in a streaming query.
*
* @param queryId - Streaming query id
* @param batchId - Batch id for a micro batch in a streaming query
*/
case class StreamingBatchId(queryId: String, batchId: Long)
Loading