com.bigdata.resources
Class CompactingMergeTask

java.lang.Object
  com.bigdata.journal.AbstractTask<T>
      com.bigdata.resources.AbstractResourceManagerTask<T>
          com.bigdata.resources.AbstractPrepareTask<BuildResult>
              com.bigdata.resources.CompactingMergeTask

All Implemented Interfaces:

ITask<BuildResult>, Callable<BuildResult>

public class CompactingMergeTask
extends AbstractPrepareTask<BuildResult>

Task builds an IndexSegment from the fused view of an index partition as of some historical timestamp and then atomically updates the view (aka a compacting merge).

Note: This task may be used after IResourceManager.overflow() in order to produce a compact view of the index as of the lastCommitTime on the old journal.

Note: As its last action, this task submits a CompactingMergeTask.AtomicUpdateCompactingMergeTask which replaces the view with one defined by the current BTree on the journal and the newly built IndexSegment.

Note: If the task fails, then the generated IndexSegment will be deleted.

Version:

$Id: CompactingMergeTask.java 3343 2010-07-29 14:55:40Z thompsonbry $

Author:

Bryan Thompson

Nested Class Summary

protected static class

CompactingMergeTask.AtomicUpdateCompactingMergeTask The source view is pre-overflow (the last writes are on the old journal) while the current view is post-overflow (reflects writes made since overflow).

Nested classes/interfaces inherited from class com.bigdata.journal.AbstractTask

AbstractTask.DelegateTask<T>, AbstractTask.InnerReadWriteTxServiceCallable, AbstractTask.InnerWriteServiceCallable<T>, AbstractTask.ResubmitException

Field Summary

protected com.bigdata.resources.ViewMetadata

vmd

Fields inherited from class com.bigdata.resources.AbstractResourceManagerTask

DEBUG, INFO, log, resourceManager

Fields inherited from class com.bigdata.journal.AbstractTask

checkpointNanoTime, concurrencyManager, isReadWriteTx, nanoTime_assignedWorker, nanoTime_beginWork, nanoTime_finishedWork, nanoTime_submitTask, readOnly, taskCounters, timestamp, transactionManager, tx

Constructor Summary

CompactingMergeTask(com.bigdata.resources.ViewMetadata vmd)

Method Summary

protected void	clearRefs() Method is responsible for clearing the SoftReferences held by ViewMetadata for the source view(s) on the old journal.
protected BuildResult	doTask() Build an IndexSegment from the compacting merge of an index partition.
protected boolean	shouldMove(ILoadBalancerService loadBalancerService) Figure out if this data service is considered to be highly utilized, in which case the DS should shed some index partitions.

Methods inherited from class com.bigdata.resources.AbstractResourceManagerTask

toString

Methods inherited from class com.bigdata.journal.AbstractTask

assertResource, assertRunning, assertUnisolated, call, clearLoggingContext, dropIndex, getCommitTime, getIndex, getJournal, getOnlyResource, getResource, getResourceManager, getTaskCounters, getTaskName, getTimestamp, isResource, registerIndex, setupLoggingContext, toString

Methods inherited from class java.lang.Object

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

Field Detail

vmd

protected final com.bigdata.resources.ViewMetadata vmd

Constructor Detail

CompactingMergeTask

public CompactingMergeTask(com.bigdata.resources.ViewMetadata vmd)

Parameters:

vmd - The ViewMetadata for the index partition.

Method Detail

clearRefs

protected void clearRefs()

Description copied from class: AbstractPrepareTask

Method is responsible for clearing the SoftReferences held by ViewMetadata for the source view(s) on the old journal.

Note: This method MUST be invoked in order to permit those references to be cleared more eagerly than the end of the entire asynchronous overflow operation (which is when the task references would themselves go out of scope and become available for GC).

Specified by:

clearRefs in class AbstractPrepareTask<BuildResult>

doTask

protected BuildResult doTask()
                      throws Exception

Build an IndexSegment from the compacting merge of an index partition.

Specified by:

doTask in class AbstractTask<BuildResult>

Returns:

The BuildResult.

Throws:

Exception - The exception that will be thrown by AbstractTask.call() iff the operation fails.

InterruptedException - This exception SHOULD be thrown if Thread.interrupted() becomes true during execution.

shouldMove

protected boolean shouldMove(ILoadBalancerService loadBalancerService)

Figure out if this data service is considered to be highly utilized, in which case the DS should shed some index partitions.

Note: We consult the load balancer service on this since it is able to put the load of this service into perspective by also considering the load on the other services in the federation.

Parameters:

loadBalancerService - The load balancer.