org.apache.lucene.index
Class ConcurrentMergeScheduler

java.lang.Object
  org.apache.lucene.index.MergeScheduler
      org.apache.lucene.index.ConcurrentMergeScheduler

public class ConcurrentMergeScheduler
extends MergeScheduler

A MergeScheduler that runs each merge using a separate thread, up until a maximum number of threads (setMaxThreadCount(int)) at which when a merge is needed, the thread(s) that are updating the index will pause until one or more merges completes. This is a simple way to use concurrency in the indexing process without having to create and manage application level threads.

Nested Class Summary

protected class

ConcurrentMergeScheduler.MergeThread

Field Summary

protected Directory	dir
protected int	mergeThreadCount
protected List<ConcurrentMergeScheduler.MergeThread>	mergeThreads
protected IndexWriter	writer

Constructor Summary

ConcurrentMergeScheduler()

Method Summary

static boolean	anyUnhandledExceptions() Used for testing
static void	clearUnhandledExceptions()
void	close() Close this MergeScheduler.
protected void	doMerge(MergePolicy.OneMerge merge) Does the actual merge, by calling IndexWriter.merge(org.apache.lucene.index.MergePolicy.OneMerge)
int	getMaxThreadCount() Get the max # simultaneous threads that may be running.
protected ConcurrentMergeScheduler.MergeThread	getMergeThread(IndexWriter writer, MergePolicy.OneMerge merge) Create and return a new MergeThread
int	getMergeThreadPriority() Return the priority that merge threads run at.
protected void	handleMergeException(Throwable exc) Called when an exception is hit in a background merge thread
void	merge(IndexWriter writer) Run the merges provided by IndexWriter.getNextMerge().
void	setMaxThreadCount(int count) Sets the max # simultaneous threads that may be running.
void	setMergeThreadPriority(int pri) Set the priority that merge threads run at.
static void	setTestMode()
void	sync()

Methods inherited from class java.lang.Object

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

Field Detail

mergeThreads

protected List<ConcurrentMergeScheduler.MergeThread> mergeThreads

dir

protected Directory dir

writer

protected IndexWriter writer

mergeThreadCount

protected int mergeThreadCount

Constructor Detail

ConcurrentMergeScheduler

public ConcurrentMergeScheduler()

Method Detail

setMaxThreadCount

public void setMaxThreadCount(int count)

Sets the max # simultaneous threads that may be running. If a merge is necessary yet we already have this many threads running, the incoming thread (that is calling add/updateDocument) will block until a merge thread has completed.

getMaxThreadCount

public int getMaxThreadCount()

Get the max # simultaneous threads that may be running. @see #setMaxThreadCount.

getMergeThreadPriority

public int getMergeThreadPriority()

Return the priority that merge threads run at. By default the priority is 1 plus the priority of (ie, slightly higher priority than) the first thread that calls merge.

setMergeThreadPriority

public void setMergeThreadPriority(int pri)

Set the priority that merge threads run at.

close

public void close()

Description copied from class: MergeScheduler

Close this MergeScheduler.

sync

public void sync()

merge

public void merge(IndexWriter writer)
           throws CorruptIndexException,
                  IOException

Description copied from class: MergeScheduler

Run the merges provided by IndexWriter.getNextMerge().

Throws:

CorruptIndexException

IOException

doMerge

protected void doMerge(MergePolicy.OneMerge merge)
                throws IOException

Does the actual merge, by calling IndexWriter.merge(org.apache.lucene.index.MergePolicy.OneMerge)

Throws:

IOException

getMergeThread

protected ConcurrentMergeScheduler.MergeThread getMergeThread(IndexWriter writer,
                                                              MergePolicy.OneMerge merge)
                                                       throws IOException

Create and return a new MergeThread

Throws:

IOException

handleMergeException

protected void handleMergeException(Throwable exc)

Called when an exception is hit in a background merge thread

anyUnhandledExceptions

public static boolean anyUnhandledExceptions()

Used for testing

clearUnhandledExceptions

public static void clearUnhandledExceptions()

setTestMode

public static void setTestMode()