Package org.apache.flink.runtime.taskexecutor.slot

Class TaskSlot<T extends TaskSlotPayload>

java.lang.Object

org.apache.flink.runtime.taskexecutor.slot.TaskSlot<T>

Type Parameters:

T - type of the TaskSlotPayload stored in this slot

All Implemented Interfaces:

AutoCloseable, AutoCloseableAsync

public class TaskSlot<T extends TaskSlotPayload>
extends Object
implements AutoCloseableAsync

Container for multiple tasks belonging to the same slot. A TaskSlot can be in one of the following states:

• Free - The slot is empty and not allocated to a job
• Releasing - The slot is about to be freed after it has become empty.
• Allocated - The slot has been allocated for a job.
• Active - The slot is in active use by a job manager which is the leader of the allocating job.

A task slot can only be allocated if it is in state free. An allocated task slot can transit to state active.

An active slot allows to add tasks from the respective job and with the correct allocation id. An active slot can be marked as inactive which sets the state back to allocated.

An allocated or active slot can only be freed if it is empty. If it is not empty, then it's state can be set to releasing indicating that it can be freed once it becomes empty.

Constructor Summary

Constructors

Constructor	Description
TaskSlot(int index, ResourceProfile resourceProfile, int memoryPageSize, JobID jobId, AllocationID allocationId, Executor asyncExecutor)

Method Summary

Modifier and Type	Method	Description
boolean	add(T task)	Add the given task to the task slot.
void	clear()	Removes all tasks from this task slot.
CompletableFuture<Void>	closeAsync()	Trigger the closing of the resource and return the corresponding close future.
SlotOffer	generateSlotOffer()	Generate the slot offer from this TaskSlot.
AllocationID	getAllocationId()
int	getIndex()
JobID	getJobId()
MemoryManager	getMemoryManager()
ResourceProfile	getResourceProfile()
Iterator<T>	getTasks()	Get all tasks running in this task slot.
boolean	isActive(JobID activeJobId, AllocationID activeAllocationId)
boolean	isAllocated(JobID jobIdToCheck, AllocationID allocationIDToCheck)
boolean	isEmpty()
boolean	isReleasing()
boolean	markActive()	Mark this slot as active.
boolean	markInactive()	Mark the slot as inactive/allocated.
T	remove(ExecutionAttemptID executionAttemptId)	Remove the task identified by the given execution attempt id.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.flink.util.AutoCloseableAsync

close

Constructor Detail

TaskSlot

public TaskSlot(int index,
                ResourceProfile resourceProfile,
                int memoryPageSize,
                JobID jobId,
                AllocationID allocationId,
                Executor asyncExecutor)

Method Detail

getIndex

public int getIndex()

getResourceProfile

public ResourceProfile getResourceProfile()

getJobId

public JobID getJobId()

getAllocationId

public AllocationID getAllocationId()

isEmpty

public boolean isEmpty()

isActive

public boolean isActive(JobID activeJobId,
                        AllocationID activeAllocationId)

isAllocated

public boolean isAllocated(JobID jobIdToCheck,
                           AllocationID allocationIDToCheck)

isReleasing

public boolean isReleasing()

getTasks

public Iterator<T> getTasks()

Get all tasks running in this task slot.

Returns:

Iterator to all currently contained tasks in this task slot.

getMemoryManager

public MemoryManager getMemoryManager()

add

public boolean add(T task)

Add the given task to the task slot. This is only possible if there is not already another task with the same execution attempt id added to the task slot. In this case, the method returns true. Otherwise the task slot is left unchanged and false is returned.

In case that the task slot state is not active an IllegalStateException is thrown. In case that the task's job id and allocation id don't match with the job id and allocation id for which the task slot has been allocated, an IllegalArgumentException is thrown.

Parameters:

task - to be added to the task slot

Returns:

true if the task was added to the task slot; otherwise false

Throws:

IllegalStateException - if the task slot is not in state active

remove

public T remove(ExecutionAttemptID executionAttemptId)

Remove the task identified by the given execution attempt id.

Parameters:

executionAttemptId - identifying the task to be removed

Returns:

The removed task if there was any; otherwise null.

clear

public void clear()

Removes all tasks from this task slot.

markActive

public boolean markActive()

Mark this slot as active. A slot can only be marked active if it's in state allocated.

The method returns true if the slot was set to active. Otherwise it returns false.

Returns:

True if the new state of the slot is active; otherwise false

markInactive

public boolean markInactive()

Mark the slot as inactive/allocated. A slot can only be marked as inactive/allocated if it's in state allocated or active.

Returns:

True if the new state of the slot is allocated; otherwise false

generateSlotOffer

public SlotOffer generateSlotOffer()

Generate the slot offer from this TaskSlot.

Returns:

The sot offer which this task slot can provide

toString

public String toString()

Overrides:

toString in class Object

closeAsync

public CompletableFuture<Void> closeAsync()

Description copied from interface: AutoCloseableAsync

Trigger the closing of the resource and return the corresponding close future.

Specified by:

closeAsync in interface AutoCloseableAsync

Returns:

Future which is completed once the resource has been closed