Package com.tangosol.net.cache

Class AbstractBundler

java.lang.Object
com.tangosol.util.Base
com.tangosol.net.cache.AbstractBundler
Direct Known Subclasses:
AbstractBinaryEntryBundler, 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

  • Field Details

    • 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 AtomicInteger 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 Details

    • 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 Details

    • 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).
      Overrides:
      toString in class Object
      Returns:
      a human readable description for the Bundler object

    • 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