org.apache.flink.runtime.instance

Class SharedSlot

java.lang.Object

org.apache.flink.runtime.instance.Slot

org.apache.flink.runtime.instance.SharedSlot

public class SharedSlot
extends Slot

This class represents a shared slot. A shared slot can have multiple SimpleSlot instances within itself. This allows to schedule multiple tasks simultaneously to the same resource. Sharing a resource with multiple tasks is crucial for simple pipelined / streamed execution, where both the sender and the receiver are typically active at the same time.

IMPORTANT: This class contains no synchronization. Thus, the caller has to guarantee proper synchronization. In the current implementation, all concurrently modifying operations are passed through a SlotSharingGroupAssignment object which is responsible for synchronization.

Field Summary

Fields inherited from class org.apache.flink.runtime.instance.Slot

NO_ALLOCATION_ID

Constructor Summary

Constructors

Constructor and Description
SharedSlot(AllocatedSlot allocatedSlot, SlotOwner owner, SlotSharingGroupAssignment assignmentGroup) Creates a new shared slot that has no parent (is a root slot) and does not belong to any task group.
SharedSlot(JobID jobID, SlotOwner owner, TaskManagerLocation location, int slotNumber, TaskManagerGateway taskManagerGateway, SlotSharingGroupAssignment assignmentGroup) Creates a new shared slot that has no parent (is a root slot) and does not belong to any task group.
SharedSlot(JobID jobID, SlotOwner owner, TaskManagerLocation location, int slotNumber, TaskManagerGateway taskManagerGateway, SlotSharingGroupAssignment assignmentGroup, SharedSlot parent, AbstractID groupId) Creates a new shared slot that has is a sub-slot of the given parent shared slot, and that belongs to the given task group.
SharedSlot(SharedSlot parent, SlotOwner owner, int slotNumber, SlotSharingGroupAssignment assignmentGroup, AbstractID groupId) Creates a new shared slot that is a sub-slot of the given parent shared slot, and that belongs to the given task group.

Method Summary

Methods

Modifier and Type	Method and Description
int	getNumberLeaves() Gets the number of simple slots that are at the leaves of the tree of slots.
boolean	hasChildren() Checks whether this shared slot has any sub slots.
boolean	isRootAndEmpty() Checks whether this slot is a root slot that has not yet added any child slots.
void	releaseSlot() This method cancels and releases the slot and all its sub-slots.
String	toString()

Methods inherited from class org.apache.flink.runtime.instance.Slot

equals, getAllocatedSlot, getGroupID, getJobID, getOwner, getParent, getRoot, getRootSlotNumber, getSlotNumber, getTaskManagerGateway, getTaskManagerID, getTaskManagerLocation, hashCode, hierarchy, isAlive, isCanceled, isReleased

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

SharedSlot

public SharedSlot(JobID jobID,
          SlotOwner owner,
          TaskManagerLocation location,
          int slotNumber,
          TaskManagerGateway taskManagerGateway,
          SlotSharingGroupAssignment assignmentGroup)

Creates a new shared slot that has no parent (is a root slot) and does not belong to any task group. This constructor is used to create a slot directly from an instance.

Parameters:

jobID - The ID of the job that the slot is created for.

owner - The component from which this slot is allocated.

location - The location info of the TaskManager where the slot was allocated from

slotNumber - The number of the slot.

taskManagerGateway - The gateway to communicate with the TaskManager

assignmentGroup - The assignment group that this shared slot belongs to.

SharedSlot

public SharedSlot(JobID jobID,
          SlotOwner owner,
          TaskManagerLocation location,
          int slotNumber,
          TaskManagerGateway taskManagerGateway,
          SlotSharingGroupAssignment assignmentGroup,
          @Nullable
          SharedSlot parent,
          @Nullable
          AbstractID groupId)

Creates a new shared slot that has is a sub-slot of the given parent shared slot, and that belongs to the given task group.

Parameters:

jobID - The ID of the job that the slot is created for.

owner - The component from which this slot is allocated.

location - The location info of the TaskManager where the slot was allocated from

slotNumber - The number of the slot.

taskManagerGateway - The gateway to communicate with the TaskManager

assignmentGroup - The assignment group that this shared slot belongs to.

parent - The parent slot of this slot.

groupId - The assignment group of this slot.

SharedSlot

public SharedSlot(AllocatedSlot allocatedSlot,
          SlotOwner owner,
          SlotSharingGroupAssignment assignmentGroup)

Creates a new shared slot that has no parent (is a root slot) and does not belong to any task group. This constructor is used to create a slot directly from an instance.

Parameters:

allocatedSlot - The allocated slot that this slot represents.

owner - The component from which this slot is allocated.

assignmentGroup - The assignment group that this shared slot belongs to.

SharedSlot

public SharedSlot(SharedSlot parent,
          SlotOwner owner,
          int slotNumber,
          SlotSharingGroupAssignment assignmentGroup,
          AbstractID groupId)

Creates a new shared slot that is a sub-slot of the given parent shared slot, and that belongs to the given task group.

Parameters:

parent - The parent slot of this slot.

owner - The component from which this slot is allocated.

slotNumber - The number of the slot.

assignmentGroup - The assignment group that this shared slot belongs to.

groupId - The assignment group of this slot.

Method Detail

getNumberLeaves

public int getNumberLeaves()

Description copied from class: Slot

Gets the number of simple slots that are at the leaves of the tree of slots.

Specified by:

getNumberLeaves in class Slot

Returns:

The number of simple slots at the leaves.

isRootAndEmpty

public boolean isRootAndEmpty()

Checks whether this slot is a root slot that has not yet added any child slots.

Returns:

True, if this slot is a root slot and has not yet added any children, false otherwise.

hasChildren

public boolean hasChildren()

Checks whether this shared slot has any sub slots.

Returns:

True, if the shared slot has sub slots, false otherwise.

releaseSlot

public void releaseSlot()

Description copied from class: Slot

This method cancels and releases the slot and all its sub-slots. After this method completed successfully, the slot will be in state "released", and the Slot.isReleased() method will return true. If this slot is a simple slot, it will be returned to its instance. If it is a shared slot, it will release all of its sub-slots and release itself.

Specified by:

releaseSlot in class Slot

toString

public String toString()

Overrides:

toString in class Slot