X-Git-Url: https://git.piment-noir.org/?a=blobdiff_plain;f=src%2Fpools%2Fabstract-pool.ts;h=eb517943a6dc74b6ec88ca9cd17f4ca5c5eb5365;hb=904f1dd1c228e9cc710aa03fab7e50bc6daa1192;hp=c6712d198bc28a9d77c08ae817e5c96c3b9227c6;hpb=028d05710d565c03bfb6a0931411f0955b81d250;p=poolifier.git

diff --git a/src/pools/abstract-pool.ts b/src/pools/abstract-pool.ts
index c6712d19..eb517943 100644
--- a/src/pools/abstract-pool.ts
+++ b/src/pools/abstract-pool.ts
@@ -5,20 +5,23 @@ import { type TransferListItem } from 'node:worker_threads'
 import type {
   MessageValue,
   PromiseResponseWrapper,
-  Task,
-  Writable
+  Task
 } from '../utility-types'
 import {
   DEFAULT_TASK_NAME,
   DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS,
   EMPTY_FUNCTION,
+  average,
   isKillBehavior,
   isPlainObject,
+  max,
   median,
+  min,
   round,
   updateMeasurementStatistics
 } from '../utils'
 import { KillBehaviors } from '../worker/worker-options'
+import type { TaskFunction } from '../worker/task-functions'
 import {
   type IPool,
   PoolEmitter,
@@ -90,6 +93,13 @@ export abstract class AbstractPool<
    */
   protected readonly max?: number
 
+  /**
+   * The task functions added at runtime map:
+   * - `key`: The task function name.
+   * - `value`: The task function itself.
+   */
+  private readonly taskFunctions: Map<string, TaskFunction<Data, Response>>
+
   /**
    * Whether the pool is starting or not.
    */
@@ -143,6 +153,8 @@ export abstract class AbstractPool<
 
     this.setupHook()
 
+    this.taskFunctions = new Map<string, TaskFunction<Data, Response>>()
+
     this.starting = true
     this.startPool()
     this.starting = false
@@ -255,19 +267,19 @@ export abstract class AbstractPool<
       )
     }
     if (
-      workerChoiceStrategyOptions.choiceRetries != null &&
-      !Number.isSafeInteger(workerChoiceStrategyOptions.choiceRetries)
+      workerChoiceStrategyOptions.retries != null &&
+      !Number.isSafeInteger(workerChoiceStrategyOptions.retries)
     ) {
       throw new TypeError(
-        'Invalid worker choice strategy options: choice retries must be an integer'
+        'Invalid worker choice strategy options: retries must be an integer'
       )
     }
     if (
-      workerChoiceStrategyOptions.choiceRetries != null &&
-      workerChoiceStrategyOptions.choiceRetries <= 0
+      workerChoiceStrategyOptions.retries != null &&
+      workerChoiceStrategyOptions.retries < 0
     ) {
       throw new RangeError(
-        `Invalid worker choice strategy options: choice retries '${workerChoiceStrategyOptions.choiceRetries}' must be greater than zero`
+        `Invalid worker choice strategy options: retries '${workerChoiceStrategyOptions.retries}' must be greater or equal than zero`
       )
     }
     if (
@@ -291,14 +303,14 @@ export abstract class AbstractPool<
   }
 
   private checkValidTasksQueueOptions (
-    tasksQueueOptions: Writable<TasksQueueOptions>
+    tasksQueueOptions: TasksQueueOptions
   ): void {
     if (tasksQueueOptions != null && !isPlainObject(tasksQueueOptions)) {
       throw new TypeError('Invalid tasks queue options: must be a plain object')
     }
     if (
       tasksQueueOptions?.concurrency != null &&
-      !Number.isSafeInteger(tasksQueueOptions.concurrency)
+      !Number.isSafeInteger(tasksQueueOptions?.concurrency)
     ) {
       throw new TypeError(
         'Invalid worker node tasks concurrency: must be an integer'
@@ -306,34 +318,28 @@ export abstract class AbstractPool<
     }
     if (
       tasksQueueOptions?.concurrency != null &&
-      tasksQueueOptions.concurrency <= 0
+      tasksQueueOptions?.concurrency <= 0
     ) {
       throw new RangeError(
-        `Invalid worker node tasks concurrency: ${tasksQueueOptions.concurrency} is a negative integer or zero`
+        `Invalid worker node tasks concurrency: ${tasksQueueOptions?.concurrency} is a negative integer or zero`
       )
     }
-    if (
-      tasksQueueOptions?.queueMaxSize != null &&
-      tasksQueueOptions?.size != null
-    ) {
+    if (tasksQueueOptions?.queueMaxSize != null) {
       throw new Error(
-        'Invalid tasks queue options: cannot specify both queueMaxSize and size'
+        'Invalid tasks queue options: queueMaxSize is deprecated, please use size instead'
       )
     }
-    if (tasksQueueOptions?.queueMaxSize != null) {
-      tasksQueueOptions.size = tasksQueueOptions.queueMaxSize
-    }
     if (
       tasksQueueOptions?.size != null &&
-      !Number.isSafeInteger(tasksQueueOptions.size)
+      !Number.isSafeInteger(tasksQueueOptions?.size)
     ) {
       throw new TypeError(
-        'Invalid worker node tasks queue max size: must be an integer'
+        'Invalid worker node tasks queue size: must be an integer'
       )
     }
-    if (tasksQueueOptions?.size != null && tasksQueueOptions.size <= 0) {
+    if (tasksQueueOptions?.size != null && tasksQueueOptions?.size <= 0) {
       throw new RangeError(
-        `Invalid worker node tasks queue max size: ${tasksQueueOptions.size} is a negative integer or zero`
+        `Invalid worker node tasks queue size: ${tasksQueueOptions?.size} is a negative integer or zero`
       )
     }
   }
@@ -404,6 +410,13 @@ export abstract class AbstractPool<
       ...(this.opts.enableTasksQueue === true && {
         backPressure: this.hasBackPressure()
       }),
+      ...(this.opts.enableTasksQueue === true && {
+        stolenTasks: this.workerNodes.reduce(
+          (accumulator, workerNode) =>
+            accumulator + workerNode.usage.tasks.stolen,
+          0
+        )
+      }),
       failedTasks: this.workerNodes.reduce(
         (accumulator, workerNode) =>
           accumulator + workerNode.usage.tasks.failed,
@@ -413,37 +426,39 @@ export abstract class AbstractPool<
         .runTime.aggregate && {
         runTime: {
           minimum: round(
-            Math.min(
+            min(
               ...this.workerNodes.map(
-                (workerNode) => workerNode.usage.runTime?.minimum ?? Infinity
+                workerNode => workerNode.usage.runTime?.minimum ?? Infinity
               )
             )
           ),
           maximum: round(
-            Math.max(
+            max(
               ...this.workerNodes.map(
-                (workerNode) => workerNode.usage.runTime?.maximum ?? -Infinity
+                workerNode => workerNode.usage.runTime?.maximum ?? -Infinity
               )
             )
           ),
-          average: round(
-            this.workerNodes.reduce(
-              (accumulator, workerNode) =>
-                accumulator + (workerNode.usage.runTime?.aggregate ?? 0),
-              0
-            ) /
-              this.workerNodes.reduce(
-                (accumulator, workerNode) =>
-                  accumulator + (workerNode.usage.tasks?.executed ?? 0),
-                0
+          ...(this.workerChoiceStrategyContext.getTaskStatisticsRequirements()
+            .runTime.average && {
+            average: round(
+              average(
+                this.workerNodes.reduce<number[]>(
+                  (accumulator, workerNode) =>
+                    accumulator.concat(workerNode.usage.runTime.history),
+                  []
+                )
               )
-          ),
+            )
+          }),
           ...(this.workerChoiceStrategyContext.getTaskStatisticsRequirements()
             .runTime.median && {
             median: round(
               median(
-                this.workerNodes.map(
-                  (workerNode) => workerNode.usage.runTime?.median ?? 0
+                this.workerNodes.reduce<number[]>(
+                  (accumulator, workerNode) =>
+                    accumulator.concat(workerNode.usage.runTime.history),
+                  []
                 )
               )
             )
@@ -454,37 +469,39 @@ export abstract class AbstractPool<
         .waitTime.aggregate && {
         waitTime: {
           minimum: round(
-            Math.min(
+            min(
               ...this.workerNodes.map(
-                (workerNode) => workerNode.usage.waitTime?.minimum ?? Infinity
+                workerNode => workerNode.usage.waitTime?.minimum ?? Infinity
               )
             )
           ),
           maximum: round(
-            Math.max(
+            max(
               ...this.workerNodes.map(
-                (workerNode) => workerNode.usage.waitTime?.maximum ?? -Infinity
+                workerNode => workerNode.usage.waitTime?.maximum ?? -Infinity
               )
             )
           ),
-          average: round(
-            this.workerNodes.reduce(
-              (accumulator, workerNode) =>
-                accumulator + (workerNode.usage.waitTime?.aggregate ?? 0),
-              0
-            ) /
-              this.workerNodes.reduce(
-                (accumulator, workerNode) =>
-                  accumulator + (workerNode.usage.tasks?.executed ?? 0),
-                0
+          ...(this.workerChoiceStrategyContext.getTaskStatisticsRequirements()
+            .waitTime.average && {
+            average: round(
+              average(
+                this.workerNodes.reduce<number[]>(
+                  (accumulator, workerNode) =>
+                    accumulator.concat(workerNode.usage.waitTime.history),
+                  []
+                )
               )
-          ),
+            )
+          }),
           ...(this.workerChoiceStrategyContext.getTaskStatisticsRequirements()
             .waitTime.median && {
             median: round(
               median(
-                this.workerNodes.map(
-                  (workerNode) => workerNode.usage.waitTime?.median ?? 0
+                this.workerNodes.reduce<number[]>(
+                  (accumulator, workerNode) =>
+                    accumulator.concat(workerNode.usage.waitTime.history),
+                  []
                 )
               )
             )
@@ -583,7 +600,7 @@ export abstract class AbstractPool<
    */
   private getWorkerNodeKeyByWorker (worker: Worker): number {
     return this.workerNodes.findIndex(
-      (workerNode) => workerNode.worker === worker
+      workerNode => workerNode.worker === worker
     )
   }
 
@@ -593,9 +610,9 @@ export abstract class AbstractPool<
    * @param workerId - The worker id.
    * @returns The worker node key if the worker id is found in the pool worker nodes, `-1` otherwise.
    */
-  private getWorkerNodeKeyByWorkerId (workerId: number): number {
+  private getWorkerNodeKeyByWorkerId (workerId: number | undefined): number {
     return this.workerNodes.findIndex(
-      (workerNode) => workerNode.info.id === workerId
+      workerNode => workerNode.info.id === workerId
     )
   }
 
@@ -650,13 +667,13 @@ export abstract class AbstractPool<
       this.checkValidTasksQueueOptions(tasksQueueOptions)
       this.opts.tasksQueueOptions =
         this.buildTasksQueueOptions(tasksQueueOptions)
-      this.setTasksQueueMaxSize(this.opts.tasksQueueOptions.size as number)
+      this.setTasksQueueSize(this.opts.tasksQueueOptions.size as number)
     } else if (this.opts.tasksQueueOptions != null) {
       delete this.opts.tasksQueueOptions
     }
   }
 
-  private setTasksQueueMaxSize (size: number): void {
+  private setTasksQueueSize (size: number): void {
     for (const workerNode of this.workerNodes) {
       workerNode.tasksQueueBackPressureSize = size
     }
@@ -699,7 +716,7 @@ export abstract class AbstractPool<
     if (this.opts.enableTasksQueue === true) {
       return (
         this.workerNodes.findIndex(
-          (workerNode) =>
+          workerNode =>
             workerNode.info.ready &&
             workerNode.usage.tasks.executing <
               (this.opts.tasksQueueOptions?.concurrency as number)
@@ -708,26 +725,143 @@ export abstract class AbstractPool<
     } else {
       return (
         this.workerNodes.findIndex(
-          (workerNode) =>
+          workerNode =>
             workerNode.info.ready && workerNode.usage.tasks.executing === 0
         ) === -1
       )
     }
   }
 
+  private async sendTaskFunctionOperationToWorker (
+    workerNodeKey: number,
+    message: MessageValue<Data>
+  ): Promise<boolean> {
+    const workerId = this.getWorkerInfo(workerNodeKey).id as number
+    return await new Promise<boolean>((resolve, reject) => {
+      this.registerWorkerMessageListener(workerNodeKey, message => {
+        if (
+          message.workerId === workerId &&
+          message.taskFunctionOperationStatus === true
+        ) {
+          resolve(true)
+        } else if (
+          message.workerId === workerId &&
+          message.taskFunctionOperationStatus === false
+        ) {
+          reject(
+            new Error(
+              `Task function operation ${
+                message.taskFunctionOperation as string
+              } failed on worker ${message.workerId}`
+            )
+          )
+        }
+      })
+      this.sendToWorker(workerNodeKey, message)
+    })
+  }
+
+  private async sendTaskFunctionOperationToWorkers (
+    message: Omit<MessageValue<Data>, 'workerId'>
+  ): Promise<boolean> {
+    return await new Promise<boolean>((resolve, reject) => {
+      const responsesReceived = new Array<MessageValue<Data | Response>>()
+      for (const [workerNodeKey] of this.workerNodes.entries()) {
+        this.registerWorkerMessageListener(workerNodeKey, message => {
+          if (message.taskFunctionOperationStatus != null) {
+            responsesReceived.push(message)
+            if (
+              responsesReceived.length === this.workerNodes.length &&
+              responsesReceived.every(
+                message => message.taskFunctionOperationStatus === true
+              )
+            ) {
+              resolve(true)
+            } else if (
+              responsesReceived.length === this.workerNodes.length &&
+              responsesReceived.some(
+                message => message.taskFunctionOperationStatus === false
+              )
+            ) {
+              reject(
+                new Error(
+                  `Task function operation ${
+                    message.taskFunctionOperation as string
+                  } failed on worker ${message.workerId as number}`
+                )
+              )
+            }
+          }
+        })
+        this.sendToWorker(workerNodeKey, message)
+      }
+    })
+  }
+
+  /** @inheritDoc */
+  public hasTaskFunction (name: string): boolean {
+    for (const workerNode of this.workerNodes) {
+      if (
+        Array.isArray(workerNode.info.taskFunctionNames) &&
+        workerNode.info.taskFunctionNames.includes(name)
+      ) {
+        return true
+      }
+    }
+    return false
+  }
+
+  /** @inheritDoc */
+  public async addTaskFunction (
+    name: string,
+    taskFunction: TaskFunction<Data, Response>
+  ): Promise<boolean> {
+    this.taskFunctions.set(name, taskFunction)
+    return await this.sendTaskFunctionOperationToWorkers({
+      taskFunctionOperation: 'add',
+      taskFunctionName: name,
+      taskFunction: taskFunction.toString()
+    })
+  }
+
   /** @inheritDoc */
-  public listTaskFunctions (): string[] {
+  public async removeTaskFunction (name: string): Promise<boolean> {
+    this.taskFunctions.delete(name)
+    return await this.sendTaskFunctionOperationToWorkers({
+      taskFunctionOperation: 'remove',
+      taskFunctionName: name
+    })
+  }
+
+  /** @inheritDoc */
+  public listTaskFunctionNames (): string[] {
     for (const workerNode of this.workerNodes) {
       if (
-        Array.isArray(workerNode.info.taskFunctions) &&
-        workerNode.info.taskFunctions.length > 0
+        Array.isArray(workerNode.info.taskFunctionNames) &&
+        workerNode.info.taskFunctionNames.length > 0
       ) {
-        return workerNode.info.taskFunctions
+        return workerNode.info.taskFunctionNames
       }
     }
     return []
   }
 
+  /** @inheritDoc */
+  public async setDefaultTaskFunction (name: string): Promise<boolean> {
+    return await this.sendTaskFunctionOperationToWorkers({
+      taskFunctionOperation: 'default',
+      taskFunctionName: name
+    })
+  }
+
+  private shallExecuteTask (workerNodeKey: number): boolean {
+    return (
+      this.tasksQueueSize(workerNodeKey) === 0 &&
+      this.workerNodes[workerNodeKey].usage.tasks.executing <
+        (this.opts.tasksQueueOptions?.concurrency as number)
+    )
+  }
+
   /** @inheritDoc */
   public async execute (
     data?: Data,
@@ -737,9 +871,11 @@ export abstract class AbstractPool<
     return await new Promise<Response>((resolve, reject) => {
       if (!this.started) {
         reject(new Error('Cannot execute a task on destroyed pool'))
+        return
       }
       if (name != null && typeof name !== 'string') {
         reject(new TypeError('name argument must be a string'))
+        return
       }
       if (
         name != null &&
@@ -747,29 +883,20 @@ export abstract class AbstractPool<
         name.trim().length === 0
       ) {
         reject(new TypeError('name argument must not be an empty string'))
+        return
       }
       if (transferList != null && !Array.isArray(transferList)) {
         reject(new TypeError('transferList argument must be an array'))
+        return
       }
       const timestamp = performance.now()
       const workerNodeKey = this.chooseWorkerNode()
-      const workerInfo = this.getWorkerInfo(workerNodeKey) as WorkerInfo
-      if (
-        name != null &&
-        Array.isArray(workerInfo.taskFunctions) &&
-        !workerInfo.taskFunctions.includes(name)
-      ) {
-        reject(
-          new Error(`Task function '${name}' is not registered in the pool`)
-        )
-      }
       const task: Task<Data> = {
         name: name ?? DEFAULT_TASK_NAME,
         // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
         data: data ?? ({} as Data),
         transferList,
         timestamp,
-        workerId: workerInfo.id as number,
         taskId: randomUUID()
       }
       this.promiseResponseMap.set(task.taskId as string, {
@@ -780,8 +907,7 @@ export abstract class AbstractPool<
       if (
         this.opts.enableTasksQueue === false ||
         (this.opts.enableTasksQueue === true &&
-          this.workerNodes[workerNodeKey].usage.tasks.executing <
-            (this.opts.tasksQueueOptions?.concurrency as number))
+          this.shallExecuteTask(workerNodeKey))
       ) {
         this.executeTask(workerNodeKey, task)
       } else {
@@ -802,18 +928,23 @@ export abstract class AbstractPool<
   }
 
   protected async sendKillMessageToWorker (
-    workerNodeKey: number,
-    workerId: number
+    workerNodeKey: number
   ): Promise<void> {
     await new Promise<void>((resolve, reject) => {
-      this.registerWorkerMessageListener(workerNodeKey, (message) => {
+      this.registerWorkerMessageListener(workerNodeKey, message => {
         if (message.kill === 'success') {
           resolve()
         } else if (message.kill === 'failure') {
-          reject(new Error(`Worker ${workerId} kill message handling failed`))
+          reject(
+            new Error(
+              `Worker ${
+                message.workerId as number
+              } kill message handling failed`
+            )
+          )
         }
       })
-      this.sendToWorker(workerNodeKey, { kill: true, workerId })
+      this.sendToWorker(workerNodeKey, { kill: true })
     })
   }
 
@@ -831,7 +962,7 @@ export abstract class AbstractPool<
    * @virtual
    */
   protected setupHook (): void {
-    // Intentionally empty
+    /* Intentionally empty */
   }
 
   /**
@@ -913,8 +1044,8 @@ export abstract class AbstractPool<
     const workerInfo = this.getWorkerInfo(workerNodeKey)
     return (
       workerInfo != null &&
-      Array.isArray(workerInfo.taskFunctions) &&
-      workerInfo.taskFunctions.length > 2
+      Array.isArray(workerInfo.taskFunctionNames) &&
+      workerInfo.taskFunctionNames.length > 2
     )
   }
 
@@ -929,7 +1060,7 @@ export abstract class AbstractPool<
     ) {
       --workerTaskStatistics.executing
     }
-    if (message.taskError == null) {
+    if (message.workerError == null) {
       ++workerTaskStatistics.executed
     } else {
       ++workerTaskStatistics.failed
@@ -940,11 +1071,13 @@ export abstract class AbstractPool<
     workerUsage: WorkerUsage,
     message: MessageValue<Response>
   ): void {
+    if (message.workerError != null) {
+      return
+    }
     updateMeasurementStatistics(
       workerUsage.runTime,
       this.workerChoiceStrategyContext.getTaskStatisticsRequirements().runTime,
-      message.taskPerformance?.runTime ?? 0,
-      workerUsage.tasks.executed
+      message.taskPerformance?.runTime ?? 0
     )
   }
 
@@ -957,8 +1090,7 @@ export abstract class AbstractPool<
     updateMeasurementStatistics(
       workerUsage.waitTime,
       this.workerChoiceStrategyContext.getTaskStatisticsRequirements().waitTime,
-      taskWaitTime,
-      workerUsage.tasks.executed
+      taskWaitTime
     )
   }
 
@@ -966,19 +1098,20 @@ export abstract class AbstractPool<
     workerUsage: WorkerUsage,
     message: MessageValue<Response>
   ): void {
+    if (message.workerError != null) {
+      return
+    }
     const eluTaskStatisticsRequirements: MeasurementStatisticsRequirements =
       this.workerChoiceStrategyContext.getTaskStatisticsRequirements().elu
     updateMeasurementStatistics(
       workerUsage.elu.active,
       eluTaskStatisticsRequirements,
-      message.taskPerformance?.elu?.active ?? 0,
-      workerUsage.tasks.executed
+      message.taskPerformance?.elu?.active ?? 0
     )
     updateMeasurementStatistics(
       workerUsage.elu.idle,
       eluTaskStatisticsRequirements,
-      message.taskPerformance?.elu?.idle ?? 0,
-      workerUsage.tasks.executed
+      message.taskPerformance?.elu?.idle ?? 0
     )
     if (eluTaskStatisticsRequirements.aggregate) {
       if (message.taskPerformance?.elu != null) {
@@ -1053,16 +1186,16 @@ export abstract class AbstractPool<
     worker.on('online', this.opts.onlineHandler ?? EMPTY_FUNCTION)
     worker.on('message', this.opts.messageHandler ?? EMPTY_FUNCTION)
     worker.on('error', this.opts.errorHandler ?? EMPTY_FUNCTION)
-    worker.on('error', (error) => {
+    worker.on('error', error => {
       const workerNodeKey = this.getWorkerNodeKeyByWorker(worker)
-      const workerInfo = this.getWorkerInfo(workerNodeKey) as WorkerInfo
+      const workerInfo = this.getWorkerInfo(workerNodeKey)
       workerInfo.ready = false
       this.workerNodes[workerNodeKey].closeChannel()
       this.emitter?.emit(PoolEvents.error, error)
       if (
         this.opts.restartWorkerOnError === true &&
-        !this.starting &&
-        this.started
+        this.started &&
+        !this.starting
       ) {
         if (workerInfo.dynamic) {
           this.createAndSetupDynamicWorkerNode()
@@ -1093,7 +1226,7 @@ export abstract class AbstractPool<
    */
   protected createAndSetupDynamicWorkerNode (): number {
     const workerNodeKey = this.createAndSetupWorkerNode()
-    this.registerWorkerMessageListener(workerNodeKey, (message) => {
+    this.registerWorkerMessageListener(workerNodeKey, message => {
       const localWorkerNodeKey = this.getWorkerNodeKeyByWorkerId(
         message.workerId
       )
@@ -1108,16 +1241,26 @@ export abstract class AbstractPool<
               workerUsage.tasks.executing === 0 &&
               this.tasksQueueSize(localWorkerNodeKey) === 0)))
       ) {
-        this.destroyWorkerNode(localWorkerNodeKey).catch((error) => {
+        this.destroyWorkerNode(localWorkerNodeKey).catch(error => {
           this.emitter?.emit(PoolEvents.error, error)
         })
       }
     })
-    const workerInfo = this.getWorkerInfo(workerNodeKey) as WorkerInfo
+    const workerInfo = this.getWorkerInfo(workerNodeKey)
     this.sendToWorker(workerNodeKey, {
-      checkActive: true,
-      workerId: workerInfo.id as number
+      checkActive: true
     })
+    if (this.taskFunctions.size > 0) {
+      for (const [taskFunctionName, taskFunction] of this.taskFunctions) {
+        this.sendTaskFunctionOperationToWorker(workerNodeKey, {
+          taskFunctionOperation: 'add',
+          taskFunctionName,
+          taskFunction: taskFunction.toString()
+        }).catch(error => {
+          this.emitter?.emit(PoolEvents.error, error)
+        })
+      }
+    }
     workerInfo.dynamic = true
     if (
       this.workerChoiceStrategyContext.getStrategyPolicy().dynamicWorkerReady ||
@@ -1183,48 +1326,24 @@ export abstract class AbstractPool<
             .runTime.aggregate,
         elu: this.workerChoiceStrategyContext.getTaskStatisticsRequirements()
           .elu.aggregate
-      },
-      workerId: (this.getWorkerInfo(workerNodeKey) as WorkerInfo).id as number
+      }
     })
   }
 
   private redistributeQueuedTasks (workerNodeKey: number): void {
     while (this.tasksQueueSize(workerNodeKey) > 0) {
-      let destinationWorkerNodeKey: number = workerNodeKey
-      let minQueuedTasks = Infinity
-      let executeTask = false
-      for (const [workerNodeId, workerNode] of this.workerNodes.entries()) {
-        if (
-          workerNode.info.ready &&
-          workerNodeId !== workerNodeKey &&
-          workerNode.usage.tasks.executing <
-            (this.opts.tasksQueueOptions?.concurrency as number)
-        ) {
-          executeTask = true
-        }
-        if (
-          workerNode.info.ready &&
-          workerNodeId !== workerNodeKey &&
-          workerNode.usage.tasks.queued === 0
-        ) {
-          destinationWorkerNodeKey = workerNodeId
-          break
-        }
-        if (
-          workerNode.info.ready &&
-          workerNodeId !== workerNodeKey &&
-          workerNode.usage.tasks.queued < minQueuedTasks
-        ) {
-          minQueuedTasks = workerNode.usage.tasks.queued
-          destinationWorkerNodeKey = workerNodeId
-        }
-      }
-      const task = {
-        ...(this.dequeueTask(workerNodeKey) as Task<Data>),
-        workerId: (this.getWorkerInfo(destinationWorkerNodeKey) as WorkerInfo)
-          .id as number
-      }
-      if (executeTask) {
+      const destinationWorkerNodeKey = this.workerNodes.reduce(
+        (minWorkerNodeKey, workerNode, workerNodeKey, workerNodes) => {
+          return workerNode.info.ready &&
+            workerNode.usage.tasks.queued <
+              workerNodes[minWorkerNodeKey].usage.tasks.queued
+            ? workerNodeKey
+            : minWorkerNodeKey
+        },
+        0
+      )
+      const task = this.dequeueTask(workerNodeKey) as Task<Data>
+      if (this.shallExecuteTask(destinationWorkerNodeKey)) {
         this.executeTask(destinationWorkerNodeKey, task)
       } else {
         this.enqueueTask(destinationWorkerNodeKey, task)
@@ -1232,39 +1351,58 @@ export abstract class AbstractPool<
     }
   }
 
+  private updateTaskStolenStatisticsWorkerUsage (
+    workerNodeKey: number,
+    taskName: string
+  ): void {
+    const workerNode = this.workerNodes[workerNodeKey]
+    if (workerNode?.usage != null) {
+      ++workerNode.usage.tasks.stolen
+    }
+    if (
+      this.shallUpdateTaskFunctionWorkerUsage(workerNodeKey) &&
+      workerNode.getTaskFunctionWorkerUsage(taskName) != null
+    ) {
+      const taskFunctionWorkerUsage = workerNode.getTaskFunctionWorkerUsage(
+        taskName
+      ) as WorkerUsage
+      ++taskFunctionWorkerUsage.tasks.stolen
+    }
+  }
+
   private taskStealingOnEmptyQueue (workerId: number): void {
     const destinationWorkerNodeKey = this.getWorkerNodeKeyByWorkerId(workerId)
-    const destinationWorkerNode = this.workerNodes[destinationWorkerNodeKey]
     const workerNodes = this.workerNodes
       .slice()
       .sort(
         (workerNodeA, workerNodeB) =>
           workerNodeB.usage.tasks.queued - workerNodeA.usage.tasks.queued
       )
-    for (const sourceWorkerNode of workerNodes) {
-      if (
-        sourceWorkerNode.info.ready &&
-        sourceWorkerNode.info.id !== workerId &&
-        sourceWorkerNode.usage.tasks.queued > 0
-      ) {
-        const task = {
-          ...(sourceWorkerNode.popTask() as Task<Data>),
-          workerId: destinationWorkerNode.info.id as number
-        }
-        if (
-          destinationWorkerNode.usage.tasks.executing <
-          (this.opts.tasksQueueOptions?.concurrency as number)
-        ) {
-          this.executeTask(destinationWorkerNodeKey, task)
-        } else {
-          this.enqueueTask(destinationWorkerNodeKey, task)
-        }
-        break
+    const sourceWorkerNode = workerNodes.find(
+      workerNode =>
+        workerNode.info.ready &&
+        workerNode.info.id !== workerId &&
+        workerNode.usage.tasks.queued > 0
+    )
+    if (sourceWorkerNode != null) {
+      const task = sourceWorkerNode.popTask() as Task<Data>
+      if (this.shallExecuteTask(destinationWorkerNodeKey)) {
+        this.executeTask(destinationWorkerNodeKey, task)
+      } else {
+        this.enqueueTask(destinationWorkerNodeKey, task)
       }
+      this.updateTaskStolenStatisticsWorkerUsage(
+        destinationWorkerNodeKey,
+        task.name as string
+      )
     }
   }
 
   private tasksStealingOnBackPressure (workerId: number): void {
+    const sizeOffset = 1
+    if ((this.opts.tasksQueueOptions?.size as number) <= sizeOffset) {
+      return
+    }
     const sourceWorkerNode =
       this.workerNodes[this.getWorkerNodeKeyByWorkerId(workerId)]
     const workerNodes = this.workerNodes
@@ -1275,23 +1413,22 @@ export abstract class AbstractPool<
       )
     for (const [workerNodeKey, workerNode] of workerNodes.entries()) {
       if (
+        sourceWorkerNode.usage.tasks.queued > 0 &&
         workerNode.info.ready &&
         workerNode.info.id !== workerId &&
-        sourceWorkerNode.usage.tasks.queued > 0 &&
-        !workerNode.hasBackPressure()
+        workerNode.usage.tasks.queued <
+          (this.opts.tasksQueueOptions?.size as number) - sizeOffset
       ) {
-        const task = {
-          ...(sourceWorkerNode.popTask() as Task<Data>),
-          workerId: workerNode.info.id as number
-        }
-        if (
-          workerNode.usage.tasks.executing <
-          (this.opts.tasksQueueOptions?.concurrency as number)
-        ) {
+        const task = sourceWorkerNode.popTask() as Task<Data>
+        if (this.shallExecuteTask(workerNodeKey)) {
           this.executeTask(workerNodeKey, task)
         } else {
           this.enqueueTask(workerNodeKey, task)
         }
+        this.updateTaskStolenStatisticsWorkerUsage(
+          workerNodeKey,
+          task.name as string
+        )
       }
     }
   }
@@ -1302,51 +1439,52 @@ export abstract class AbstractPool<
    * @returns The listener function to execute when a message is received from a worker.
    */
   protected workerListener (): (message: MessageValue<Response>) => void {
-    return (message) => {
+    return message => {
       this.checkMessageWorkerId(message)
-      if (message.ready != null && message.taskFunctions != null) {
+      if (message.ready != null && message.taskFunctionNames != null) {
         // Worker ready response received from worker
         this.handleWorkerReadyResponse(message)
       } else if (message.taskId != null) {
         // Task execution response received from worker
         this.handleTaskExecutionResponse(message)
-      } else if (message.taskFunctions != null) {
-        // Task functions message received from worker
-        (
-          this.getWorkerInfo(
-            this.getWorkerNodeKeyByWorkerId(message.workerId)
-          ) as WorkerInfo
-        ).taskFunctions = message.taskFunctions
+      } else if (message.taskFunctionNames != null) {
+        // Task function names message received from worker
+        this.getWorkerInfo(
+          this.getWorkerNodeKeyByWorkerId(message.workerId)
+        ).taskFunctionNames = message.taskFunctionNames
       }
     }
   }
 
   private handleWorkerReadyResponse (message: MessageValue<Response>): void {
     if (message.ready === false) {
-      throw new Error(`Worker ${message.workerId} failed to initialize`)
+      throw new Error(
+        `Worker ${message.workerId as number} failed to initialize`
+      )
     }
     const workerInfo = this.getWorkerInfo(
       this.getWorkerNodeKeyByWorkerId(message.workerId)
-    ) as WorkerInfo
+    )
     workerInfo.ready = message.ready as boolean
-    workerInfo.taskFunctions = message.taskFunctions
+    workerInfo.taskFunctionNames = message.taskFunctionNames
     if (this.emitter != null && this.ready) {
       this.emitter.emit(PoolEvents.ready, this.info)
     }
   }
 
   private handleTaskExecutionResponse (message: MessageValue<Response>): void {
-    const { taskId, taskError, data } = message
+    const { taskId, workerError, data } = message
     const promiseResponse = this.promiseResponseMap.get(taskId as string)
     if (promiseResponse != null) {
-      if (taskError != null) {
-        this.emitter?.emit(PoolEvents.taskError, taskError)
-        promiseResponse.reject(taskError.message)
+      if (workerError != null) {
+        this.emitter?.emit(PoolEvents.taskError, workerError)
+        promiseResponse.reject(workerError.message)
       } else {
         promiseResponse.resolve(data as Response)
       }
       const workerNodeKey = promiseResponse.workerNodeKey
       this.afterTaskExecutionHook(workerNodeKey, message)
+      this.workerChoiceStrategyContext.update(workerNodeKey)
       this.promiseResponseMap.delete(taskId as string)
       if (
         this.opts.enableTasksQueue === true &&
@@ -1359,7 +1497,6 @@ export abstract class AbstractPool<
           this.dequeueTask(workerNodeKey) as Task<Data>
         )
       }
-      this.workerChoiceStrategyContext.update(workerNodeKey)
     }
   }
 
@@ -1389,8 +1526,8 @@ export abstract class AbstractPool<
    * @param workerNodeKey - The worker node key.
    * @returns The worker information.
    */
-  protected getWorkerInfo (workerNodeKey: number): WorkerInfo | undefined {
-    return this.workerNodes[workerNodeKey]?.info
+  protected getWorkerInfo (workerNodeKey: number): WorkerInfo {
+    return this.workerNodes[workerNodeKey].info
   }
 
   /**
@@ -1403,7 +1540,6 @@ export abstract class AbstractPool<
   private addWorkerNode (worker: Worker): number {
     const workerNode = new WorkerNode<Worker, Data>(
       worker,
-      this.worker,
       this.opts.tasksQueueOptions?.size ?? Math.pow(this.maxSize, 2)
     )
     // Flag the worker node as ready at pool startup.
@@ -1413,7 +1549,7 @@ export abstract class AbstractPool<
     this.workerNodes.push(workerNode)
     const workerNodeKey = this.getWorkerNodeKeyByWorker(worker)
     if (workerNodeKey === -1) {
-      throw new Error('Worker node added not found')
+      throw new Error('Worker added not found in worker nodes')
     }
     return workerNodeKey
   }
@@ -1443,7 +1579,7 @@ export abstract class AbstractPool<
     return (
       this.opts.enableTasksQueue === true &&
       this.workerNodes.findIndex(
-        (workerNode) => !workerNode.hasBackPressure()
+        workerNode => !workerNode.hasBackPressure()
       ) === -1
     )
   }