How to use

PooledConcurrentMergeScheduler

in

org.apache.lucene.index

@Override
public void merge( IndexWriter writer, MergeTrigger trigger, boolean newMergesFound )
    throws IOException
{
  while ( true )
  {
    MergePolicy.OneMerge merge = writer.getNextMerge();
    if ( merge == null )
    {
      return;
    }
    boolean success = false;
    try
    {
      MergeThread mergeThread = getMergeThread( writer, merge );
      writerTaskCounter.increment();
      PooledConcurrentMergePool.mergeThreadsPool.submit( mergeTask( mergeThread ) );
      success = true;
    }
    finally
    {
      if ( !success )
      {
        writer.mergeFinish( merge );
        writerTaskCounter.decrement();
      }
    }
  }
}

@Override
public void close()
{
  waitForAllTasks();
  super.close();
}

public static IndexWriterConfig standard( Analyzer analyzer )
{
  IndexWriterConfig writerConfig = new IndexWriterConfig( analyzer );
  writerConfig.setMaxBufferedDocs( MAX_BUFFERED_DOCS );
  writerConfig.setMaxBufferedDeleteTerms( MAX_BUFFERED_DELETE_TERMS );
  writerConfig.setIndexDeletionPolicy( new SnapshotDeletionPolicy( new KeepOnlyLastCommitDeletionPolicy() ) );
  writerConfig.setUseCompoundFile( true );
  writerConfig.setRAMBufferSizeMB( STANDARD_RAM_BUFFER_SIZE_MB );
  writerConfig.setCodec(new Lucene54Codec()
  {
    @Override
    public PostingsFormat getPostingsFormatForField( String field )
    {
      PostingsFormat postingFormat = super.getPostingsFormatForField( field );
      return CODEC_BLOCK_TREE_ORDS_POSTING_FORMAT ? blockTreeOrdsPostingsFormat : postingFormat;
    }
  });
  if ( CUSTOM_MERGE_SCHEDULER )
  {
    writerConfig.setMergeScheduler( new PooledConcurrentMergeScheduler() );
  }
  LogByteSizeMergePolicy mergePolicy = new LogByteSizeMergePolicy();
  mergePolicy.setNoCFSRatio( MERGE_POLICY_NO_CFS_RATIO );
  mergePolicy.setMinMergeMB( MERGE_POLICY_MIN_MERGE_MB );
  mergePolicy.setMergeFactor( MERGE_POLICY_MERGE_FACTOR );
  writerConfig.setMergePolicy( mergePolicy );
  return writerConfig;
}