com.tangosol.net.cache
Class AbstractBundler

java.lang.Object
  com.tangosol.util.Base
      com.tangosol.net.cache.AbstractBundler

Direct Known Subclasses:

AbstractEntryBundler, AbstractKeyBundler

public abstract class AbstractBundler
extends Base

An abstract base for processors that implement bundling strategy.

Assume that we receive a continuous and concurrent stream of individual operations on multiple threads in parallel. Let's also assume those individual operations have relatively high latency (network or database-related) and there are functionally analogous [bulk] operations that take a collection of arguments instead of a single one without causing the latency to grow linearly, as a function of the collection size. Examples of operations and topologies that satisfy these assumptions are:

• get() and getAll() methods for the NamedCache API for the partitioned cache service topology;
• put() and putAll() methods for the NamedCache API for the partitioned cache service topology;
• load() and loadAll() methods for the CacheLoader API for the read-through backing map topology;
• store() and storeAll() methods for the CacheStore API for the write-through backing map topology.

Under these assumptions, it's quite clear that the bundler could achieve a better utilization of system resources and better throughput if slightly delays the individual execution requests with a purpose of "bundling" them together and passing into a corresponding bulk operation. Additionally, the "bundled" request should be triggered if a bundle reaches a "preferred bundle size" threshold, eliminating a need to wait till a bundle timeout is reached.

Note: we assume that all bundle-able operations are idempotent and could be repeated if un-bundling is necessary due to a bundled operation failure.

Since:

Coherence 3.3

Author:

gg 2007.01.28

Nested Class Summary

protected class	AbstractBundler.Bundle
protected static class	AbstractBundler.Statistics Statistics class contains the latest bundler statistics.

Field Summary

static int	ADJUSTMENT_FREQUENCY Frequency of the adjustment attempts.
protected AtomicCounter	m_countThreads A counter for the total number of threads that have started any bundle related execution.
protected double	m_dPreviousSizeThreshold The previous bundle size threshold value.
protected List	m_listBundle A pool of Bundle objects.

Constructor Summary

AbstractBundler()
Construct the bundler.

Method Summary

void	adjust() Adjust this Bundler's parameters according to the available statistical information.
long	getDelayMillis() Obtain the timeout delay value.
protected AbstractBundler.Bundle	getOpenBundle() Retrieve any Bundle that is currently in the open state.
int	getSizeThreshold() Obtain the bundle size threshold value.
int	getThreadThreshold() Obtains the minimum number of threads that will trigger the bundler to switch from a pass through to a bundled mode.
protected abstract AbstractBundler.Bundle	instantiateBundle() Instantiate a new Bundle object.
boolean	isAllowAutoAdjust() Check whether or not the auto-adjustment is allowed.
void	resetStatistics() Reset this Bundler statistics.
void	setAllowAutoAdjust(boolean fAutoAdjust) Specify whether or not the auto-adjustment is allowed..
void	setDelayMillis(long lDelay) Specify the timeout delay value.
void	setSizeThreshold(int cSize) Specify the bundle size threshold value.
void	setThreadThreshold(int cThreads) Specify the minimum number of threads that will trigger the bundler to switch from a pass through to a bundled mode.
String	toString() Provide a human readable description for the Bundler object (for debugging).
protected void	updateStatistics() Update the statistics for this Bundle.

Field Detail

ADJUSTMENT_FREQUENCY

public static int ADJUSTMENT_FREQUENCY

Frequency of the adjustment attempts. This number represents a number of iterations of the master bundle usage after which an adjustment attempt will be performed.

m_dPreviousSizeThreshold

protected double m_dPreviousSizeThreshold

The previous bundle size threshold value.

m_listBundle

protected List m_listBundle

A pool of Bundle objects. Note that this list never shrinks.

m_countThreads

protected AtomicCounter m_countThreads

A counter for the total number of threads that have started any bundle related execution. This counter is used by subclasses to reduce an impact of bundled execution for lightly loaded environments.

Constructor Detail

AbstractBundler

public AbstractBundler()

Construct the bundler. By default, the timeout delay value is set to one millisecond and the auto-adjustment feature is turned on.

Method Detail

getSizeThreshold

public int getSizeThreshold()

Obtain the bundle size threshold value.

Returns:

the bundle size threshold value expressed in the same units as the value returned by the AbstractBundler.Bundle.getBundleSize() method

setSizeThreshold

public void setSizeThreshold(int cSize)

Specify the bundle size threshold value.

Parameters:

cSize - the bundle size threshold value; must be positive value expressed in the same units as the value returned by the AbstractBundler.Bundle.getBundleSize() method

getThreadThreshold

public int getThreadThreshold()

Obtains the minimum number of threads that will trigger the bundler to switch from a pass through to a bundled mode.

Returns:

a the number of threads threshold

setThreadThreshold

public void setThreadThreshold(int cThreads)

Specify the minimum number of threads that will trigger the bundler to switch from a pass through to a bundled mode.

Parameters:

cThreads - the number of threads threshold

getDelayMillis

public long getDelayMillis()

Obtain the timeout delay value.

Returns:

the timeout delay value in milliseconds

setDelayMillis

public void setDelayMillis(long lDelay)

Specify the timeout delay value.

Parameters:

lDelay - the timeout delay value in milliseconds

isAllowAutoAdjust

public boolean isAllowAutoAdjust()

Check whether or not the auto-adjustment is allowed.

Returns:

true iff the auto-adjustment is allowed

setAllowAutoAdjust

public void setAllowAutoAdjust(boolean fAutoAdjust)

Specify whether or not the auto-adjustment is allowed..

Parameters:

fAutoAdjust - true if the auto-adjustment should be allowed; false otherwise

updateStatistics

protected void updateStatistics()

Update the statistics for this Bundle.

resetStatistics

public void resetStatistics()

Reset this Bundler statistics.

adjust

public void adjust()

Adjust this Bundler's parameters according to the available statistical information.

toString

public String toString()

Provide a human readable description for the Bundler object (for debugging).

Returns:

a human readable description for the Bundler obect

getOpenBundle

protected AbstractBundler.Bundle getOpenBundle()

Retrieve any Bundle that is currently in the open state. This method does not assume any external synchronization and as a result, a caller must double check the returned bundle open state (after synchronizing on it).

Returns:

an open Bundle

instantiateBundle

protected abstract AbstractBundler.Bundle instantiateBundle()

Instantiate a new Bundle object.

Returns:

a new Bundle object