org.apache.giraph.ooc.policy

Class FixedPartitionsOracle

java.lang.Object

org.apache.giraph.ooc.policy.FixedPartitionsOracle

All Implemented Interfaces:

OutOfCoreOracle

public class FixedPartitionsOracle
extends Object
implements OutOfCoreOracle

Oracle for fixed out-of-core mechanism

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.giraph.ooc.policy.OutOfCoreOracle

OutOfCoreOracle.IOAction

Constructor Summary

Constructors

Constructor and Description
FixedPartitionsOracle(ImmutableClassesGiraphConfiguration conf, OutOfCoreEngine oocEngine) Constructor

Method Summary

Modifier and Type	Method and Description
boolean	approve(IOCommand command) Whether a command is appropriate to bring the memory to a more desired state.
void	commandCompleted(IOCommand command) Notification of command completion.
void	gcCompleted(com.sun.management.GarbageCollectionNotificationInfo gcInfo) Notification of GC completion.
OutOfCoreOracle.IOAction[]	getNextIOActions() Get the next set of viable IO actions to help bring memory to a more desired state.
void	startIteration() Called at the beginning of a superstep.

Methods inherited from class java.lang.Object

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

Constructor Detail

FixedPartitionsOracle

public FixedPartitionsOracle(ImmutableClassesGiraphConfiguration conf,
                             OutOfCoreEngine oocEngine)

Constructor

Parameters:

conf - configuration

oocEngine - out-of-core engine

Method Detail

getNextIOActions

public OutOfCoreOracle.IOAction[] getNextIOActions()

Description copied from interface: OutOfCoreOracle

Get the next set of viable IO actions to help bring memory to a more desired state.

Specified by:

getNextIOActions in interface OutOfCoreOracle

Returns:

an array of viable IO actions, sorted from highest priority to lowest priority

approve

public boolean approve(IOCommand command)

Description copied from interface: OutOfCoreOracle

Whether a command is appropriate to bring the memory to a more desired state. A command is not executed unless it is approved by the oracle. This method is specially important where there are multiple IO threads performing IO operations for the out-of-core mechanism. The approval becomes significantly important to prevent all IO threads from performing identical command type, if that is a necessity. For instance, execution of a particular command type by only one thread may bring the memory to a desired state, and the rest of IO threads may perform other types of commands.

Specified by:

approve in interface OutOfCoreOracle

Parameters:

command - the IO command that is about to execute

Returns:

'true' if the command is approved for execution. 'false' if the command should not be executed

commandCompleted

public void commandCompleted(IOCommand command)

Description copied from interface: OutOfCoreOracle

Notification of command completion. Oracle may update its status and commit the changes a command may cause.

Specified by:

commandCompleted in interface OutOfCoreOracle

Parameters:

command - the IO command that is completed

gcCompleted

public void gcCompleted(com.sun.management.GarbageCollectionNotificationInfo gcInfo)

Description copied from interface: OutOfCoreOracle

Notification of GC completion. Oracle may take certain decisions based on GC information (such as amount of time it took, memory it reclaimed, etc.)

Specified by:

gcCompleted in interface OutOfCoreOracle

Parameters:

gcInfo - GC information

startIteration

public void startIteration()

Description copied from interface: OutOfCoreOracle

Called at the beginning of a superstep.

Specified by:

startIteration in interface OutOfCoreOracle