Package org.apache.ignite.internal.processors.cache.persistence.pagemem

Class PagesWriteSpeedBasedThrottle

java.lang.Object

org.apache.ignite.internal.processors.cache.persistence.pagemem.PagesWriteSpeedBasedThrottle

All Implemented Interfaces:

PagesWriteThrottlePolicy

public class PagesWriteSpeedBasedThrottle
extends Object
implements PagesWriteThrottlePolicy

Throttles threads that generate dirty pages during ongoing checkpoint. Designed to avoid zero dropdowns that can happen if checkpoint buffer is overflowed. When the page in question is not included in the current checkpoint and Checkpoint Buffer is filled over 2/3, uses exponentially growing sleep time to throttle. Otherwise, uses average checkpoint write speed and instant speed of marking pages as dirty.

See Also:

Speed-based throttling description

Field Summary

Fields inherited from interface org.apache.ignite.internal.processors.cache.persistence.pagemem.PagesWriteThrottlePolicy

CP_BUF_FILL_THRESHOLD, DFLT_THROTTLE_LOG_THRESHOLD, LOGGING_THRESHOLD

Constructor Summary

Constructors

Constructor	Description
PagesWriteSpeedBasedThrottle(PageMemoryImpl pageMemory, IgniteOutClosure<CheckpointProgress> cpProgress, CheckpointLockStateChecker stateChecker, IgniteLogger log)

Method Summary

Modifier and Type	Method	Description
protected void	doPark(long throttleParkTimeNs)	Disables the current thread for thread scheduling purposes.
long	getCpWriteSpeed()
double	getCurrDirtyRatio()
long	getLastEstimatedSpeedForMarkAll()
long	getMarkDirtySpeed()
double	getTargetDirtyRatio()
boolean	isCpBufferOverflowThresholdExceeded()	Whether Checkpoint Buffer is currently close to exhaustion.
void	onBeginCheckpoint()	Callback to notify throttling policy checkpoint was started.
void	onFinishCheckpoint()	Callback to notify throttling policy checkpoint was finished.
void	onMarkDirty(boolean isPageInCheckpoint)	Callback to apply throttling delay.
long	throttleParkTime()
double	throttleWeight()	Measurement shows how much throttling time is involved into average marking time.
void	wakeupThrottledThreads()	Callback to wakeup throttled threads.

Methods inherited from class java.lang.Object

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

Constructor Detail

PagesWriteSpeedBasedThrottle

public PagesWriteSpeedBasedThrottle(PageMemoryImpl pageMemory,
                                    IgniteOutClosure<CheckpointProgress> cpProgress,
                                    CheckpointLockStateChecker stateChecker,
                                    IgniteLogger log)

Parameters:

pageMemory - Page memory.

cpProgress - Database manager.

stateChecker - Checkpoint lock state provider.

log - Logger.

Method Detail

onMarkDirty

public void onMarkDirty(boolean isPageInCheckpoint)

Callback to apply throttling delay.

Specified by:

onMarkDirty in interface PagesWriteThrottlePolicy

Parameters:

isPageInCheckpoint - flag indicating if current page is in scope of current checkpoint.

doPark

protected void doPark(long throttleParkTimeNs)

Disables the current thread for thread scheduling purposes. May be overriden by subclasses for tests

Parameters:

throttleParkTimeNs - the maximum number of nanoseconds to wait

onBeginCheckpoint

public void onBeginCheckpoint()

Callback to notify throttling policy checkpoint was started.

Specified by:

onBeginCheckpoint in interface PagesWriteThrottlePolicy

onFinishCheckpoint

public void onFinishCheckpoint()

Callback to notify throttling policy checkpoint was finished.

Specified by:

onFinishCheckpoint in interface PagesWriteThrottlePolicy

throttleParkTime

public long throttleParkTime()

Returns:

Exponential backoff counter.

getTargetDirtyRatio

public double getTargetDirtyRatio()

Returns:

Target (maximum) dirty pages ratio, after which throttling will start.

getCurrDirtyRatio

public double getCurrDirtyRatio()

Returns:

Current dirty pages ratio.

getMarkDirtySpeed

public long getMarkDirtySpeed()

Returns:

Speed of marking pages dirty. Value from past 750-1000 millis only. Pages/second.

getCpWriteSpeed

public long getCpWriteSpeed()

Returns:

Speed average checkpoint write speed. Current and 3 past checkpoints used. Pages/second.

getLastEstimatedSpeedForMarkAll

public long getLastEstimatedSpeedForMarkAll()

Returns:

last estimated speed for marking all clear pages as dirty till the end of checkpoint.

throttleWeight

public double throttleWeight()

Measurement shows how much throttling time is involved into average marking time.

Returns:

metric started from 0.0 and showing how much throttling is involved into current marking process.

wakeupThrottledThreads

public void wakeupThrottledThreads()

Callback to wakeup throttled threads. Invoked when the Checkpoint Buffer use drops below a certain threshold.

Specified by:

wakeupThrottledThreads in interface PagesWriteThrottlePolicy

isCpBufferOverflowThresholdExceeded

public boolean isCpBufferOverflowThresholdExceeded()

Whether Checkpoint Buffer is currently close to exhaustion.

Specified by:

isCpBufferOverflowThresholdExceeded in interface PagesWriteThrottlePolicy

Returns:

true if measures like throttling to protect Checkpoint Buffer should be applied, and false otherwise.