com.github.benmanes.caffeine.cache.simulator.policy.sketch

Class WindowTinyLfuPolicy

java.lang.Object

com.github.benmanes.caffeine.cache.simulator.policy.sketch.WindowTinyLfuPolicy

All Implemented Interfaces:

Policy, Policy.KeyOnlyPolicy

public final class WindowTinyLfuPolicy
extends Object
implements Policy.KeyOnlyPolicy

An adaption of the TinyLfu policy that adds a temporal admission window. This window allows the policy to have a high hit rate when entries exhibit a high temporal / low frequency pattern.

A new entry starts in the window and remains there as long as it has high temporal locality. Eventually an entry will slip from the end of the window onto the front of the main queue. If the main queue is already full, then a historic frequency filter determines whether to evict the newly admitted entry or the victim entry chosen by main queue's policy. This process ensures that the entries in the main queue have both a high recency and frequency. The window space uses LRU and the main uses Segmented LRU.

Scan resistance is achieved by means of the window. Transient data will pass through from the window and not be accepted into the main queue. Responsiveness is maintained by the main queue's LRU and the TinyLfu's reset operation so that expired long term entries fade away.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	WindowTinyLfuPolicy.WindowTinyLfuSettings

Nested classes/interfaces inherited from interface com.github.benmanes.caffeine.cache.simulator.policy.Policy

Policy.Characteristic, Policy.KeyOnlyPolicy, Policy.PolicySpec

Constructor Summary

Constructors

Constructor and Description
WindowTinyLfuPolicy(double percentMain, WindowTinyLfuPolicy.WindowTinyLfuSettings settings)

Method Summary

Modifier and Type	Method and Description
void	finished() Indicates that the recording has completed.
static Set<Policy>	policies(Config config) Returns all variations of this policy based on the configuration parameters.
void	record(long key)
PolicyStats	stats() Returns the cache efficiency statistics.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.github.benmanes.caffeine.cache.simulator.policy.Policy.KeyOnlyPolicy

record

Methods inherited from interface com.github.benmanes.caffeine.cache.simulator.policy.Policy

name

Constructor Detail

WindowTinyLfuPolicy

public WindowTinyLfuPolicy(double percentMain,
                           WindowTinyLfuPolicy.WindowTinyLfuSettings settings)

Method Detail

policies

public static Set<Policy> policies(Config config)

Returns all variations of this policy based on the configuration parameters.

stats

public PolicyStats stats()

Description copied from interface: Policy

Returns the cache efficiency statistics.

Specified by:

stats in interface Policy

record

public void record(long key)

Specified by:

record in interface Policy.KeyOnlyPolicy

finished

public void finished()

Description copied from interface: Policy

Indicates that the recording has completed.

Specified by:

finished in interface Policy