Package org.apache.flink.state.forst.fs.cache

Class SpaceBasedCacheLimitPolicy

java.lang.Object

org.apache.flink.state.forst.fs.cache.SpaceBasedCacheLimitPolicy

All Implemented Interfaces:

CacheLimitPolicy

public class SpaceBasedCacheLimitPolicy
extends Object
implements CacheLimitPolicy

A space based cache limit policy that leverages the system to check the free space dynamically, the free space may fluctuate in size due to other components. This class is not thread-safe, and the thread safe should be ensured by the invoker.

Constructor Summary

Constructors

Constructor	Description
SpaceBasedCacheLimitPolicy(File instanceBasePath, long reservedSize, long baseTargetFileSize)

Method Summary

Modifier and Type	Method	Description
void	acquire(long toAddSize)	Acquire cache.
boolean	directWriteInCache()	Whether to support directly write in cache.
boolean	isOverflow(long toAddSize, boolean hasFile)	Whether the cache usage is exceeded the upperbound.
boolean	isSafeToAdd(long toAddSize)	Whether the cache usage is safe to add.
void	registerCustomizedMetrics(String prefix, org.apache.flink.metrics.MetricGroup metricGroup)	Register customized metrics.
void	release(long toReleaseSize)	Release cache.
String	toString()
long	usedBytes()	Get current used bytes.
static boolean	worksOn(File instanceBasePath)

Methods inherited from class java.lang.Object

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

Constructor Detail

SpaceBasedCacheLimitPolicy

public SpaceBasedCacheLimitPolicy(File instanceBasePath,
                                  long reservedSize,
                                  long baseTargetFileSize)

Method Detail

worksOn

public static boolean worksOn(File instanceBasePath)

directWriteInCache

public boolean directWriteInCache()

Description copied from interface: CacheLimitPolicy

Whether to support directly write in cache.

Specified by:

directWriteInCache in interface CacheLimitPolicy

isSafeToAdd

public boolean isSafeToAdd(long toAddSize)

Description copied from interface: CacheLimitPolicy

Whether the cache usage is safe to add.

Specified by:

isSafeToAdd in interface CacheLimitPolicy

Returns:

false if the toAddSize is larger than max available capacity, true otherwise.

isOverflow

public boolean isOverflow(long toAddSize,
                          boolean hasFile)

Description copied from interface: CacheLimitPolicy

Whether the cache usage is exceeded the upperbound.

Specified by:

isOverflow in interface CacheLimitPolicy

Parameters:

toAddSize - the size about to add.

hasFile - whether the file is already in cache.

Returns:

true if the cache usage is overflow, false otherwise.

acquire

public void acquire(long toAddSize)

Description copied from interface: CacheLimitPolicy

Acquire cache.

Specified by:

acquire in interface CacheLimitPolicy

release

public void release(long toReleaseSize)

Description copied from interface: CacheLimitPolicy

Release cache.

Specified by:

release in interface CacheLimitPolicy

usedBytes

public long usedBytes()

Description copied from interface: CacheLimitPolicy

Get current used bytes.

Specified by:

usedBytes in interface CacheLimitPolicy

Returns:

cache bytes.

registerCustomizedMetrics

public void registerCustomizedMetrics(String prefix,
                                      org.apache.flink.metrics.MetricGroup metricGroup)

Description copied from interface: CacheLimitPolicy

Register customized metrics.

Specified by:

registerCustomizedMetrics in interface CacheLimitPolicy

toString

public String toString()

Overrides:

toString in class Object