Index: lucene/CHANGES.txt --- lucene/CHANGES.txt Mon Mar 14 13:57:08 2011 -0400 +++ lucene/CHANGES.txt Mon Mar 14 17:53:45 2011 -0400 @@ -362,6 +362,10 @@ * LUCENE-2936: PhraseQuery score explanations were not correctly identifying matches vs non-matches. (hossman) +* LUCENE-2960: Allow some changes to IndexWriterConfig to take effect + "live" (after an IW is instantiated), via IndexWriter.getConfig() + (Shay Banon, Mike McCandless) + ======================= Lucene 3.x (not yet released) ======================= (No changes) Index: lucene/src/java/org/apache/lucene/index/BufferedDeletesStream.java --- lucene/src/java/org/apache/lucene/index/BufferedDeletesStream.java Mon Mar 14 13:57:08 2011 -0400 +++ lucene/src/java/org/apache/lucene/index/BufferedDeletesStream.java Mon Mar 14 17:53:45 2011 -0400 @@ -61,7 +61,7 @@ // used only by assert private Term lastDeleteTerm; - private PrintStream infoStream; + private volatile PrintStream infoStream; private final AtomicLong bytesUsed = new AtomicLong(); private final AtomicInteger numTerms = new AtomicInteger(); private final int messageID; Index: lucene/src/java/org/apache/lucene/index/DocumentsWriter.java --- lucene/src/java/org/apache/lucene/index/DocumentsWriter.java Mon Mar 14 13:57:08 2011 -0400 +++ lucene/src/java/org/apache/lucene/index/DocumentsWriter.java Mon Mar 14 17:53:45 2011 -0400 @@ -128,7 +128,7 @@ boolean bufferIsFull; // True when it's time to write segment private boolean aborting; // True if an abort is pending - PrintStream infoStream; + volatile PrintStream infoStream; SimilarityProvider similarityProvider; // max # simultaneous threads; if there are more than @@ -266,17 +266,8 @@ // How much RAM we can use before flushing. This is 0 if // we are flushing by doc count instead. - private long ramBufferSize = (long) (IndexWriterConfig.DEFAULT_RAM_BUFFER_SIZE_MB*1024*1024); - private long waitQueuePauseBytes = (long) (ramBufferSize*0.1); - private long waitQueueResumeBytes = (long) (ramBufferSize*0.05); - // If we've allocated 5% over our RAM budget, we then - // free down to 95% - private long freeLevel = (long) (IndexWriterConfig.DEFAULT_RAM_BUFFER_SIZE_MB*1024*1024*0.95); - - // Flush @ this number of docs. If ramBufferSize is - // non-zero we will flush by RAM usage instead. - private int maxBufferedDocs = IndexWriterConfig.DEFAULT_MAX_BUFFERED_DOCS; + private final IndexWriterConfig config; private boolean closed; private final FieldInfos fieldInfos; @@ -284,7 +275,7 @@ private final BufferedDeletesStream bufferedDeletesStream; private final IndexWriter.FlushControl flushControl; - DocumentsWriter(Directory directory, IndexWriter writer, IndexingChain indexingChain, int maxThreadStates, FieldInfos fieldInfos, BufferedDeletesStream bufferedDeletesStream) throws IOException { + DocumentsWriter(IndexWriterConfig config, Directory directory, IndexWriter writer, IndexingChain indexingChain, int maxThreadStates, FieldInfos fieldInfos, BufferedDeletesStream bufferedDeletesStream) throws IOException { this.directory = directory; this.writer = writer; this.similarityProvider = writer.getConfig().getSimilarityProvider(); @@ -294,6 +285,7 @@ flushControl = writer.flushControl; consumer = indexingChain.getChain(this); + this.config = config; } // Buffer a specific docID for deletion. Currently only @@ -363,45 +355,6 @@ } } - synchronized void setSimilarityProvider(SimilarityProvider similarity) { - this.similarityProvider = similarity; - for(int i=0;i freeLevel) { synchronized(this) { @@ -1117,10 +1080,24 @@ } synchronized boolean doResume() { + final double mb = config.getRAMBufferSizeMB(); + final long waitQueueResumeBytes; + if (mb == IndexWriterConfig.DISABLE_AUTO_FLUSH) { + waitQueueResumeBytes = 2*1024*1024; + } else { + waitQueueResumeBytes = (long) (mb*1024*1024*0.05); + } return waitingBytes <= waitQueueResumeBytes; } synchronized boolean doPause() { + final double mb = config.getRAMBufferSizeMB(); + final long waitQueuePauseBytes; + if (mb == IndexWriterConfig.DISABLE_AUTO_FLUSH) { + waitQueuePauseBytes = 4*1024*1024; + } else { + waitQueuePauseBytes = (long) (mb*1024*1024*0.1); + } return waitingBytes > waitQueuePauseBytes; } Index: lucene/src/java/org/apache/lucene/index/IndexWriter.java --- lucene/src/java/org/apache/lucene/index/IndexWriter.java Mon Mar 14 13:57:08 2011 -0400 +++ lucene/src/java/org/apache/lucene/index/IndexWriter.java Mon Mar 14 17:53:45 2011 -0400 @@ -230,8 +230,6 @@ private Lock writeLock; - private final int termIndexInterval; - private boolean closed; private boolean closing; @@ -689,10 +687,9 @@ /** * Constructs a new IndexWriter per the settings given in conf. - * Note that the passed in {@link IndexWriterConfig} is cloned and thus making - * changes to it after IndexWriter has been instantiated will not affect - * IndexWriter. Additionally, calling {@link #getConfig()} and changing the - * parameters does not affect that IndexWriter instance. + * Note that the passed in {@link IndexWriterConfig} is + * privately cloned; if you need to make subsequent "live" + * changes to the configuration use {@link #getConfig}. *

* * @param d @@ -718,11 +715,9 @@ directory = d; analyzer = conf.getAnalyzer(); infoStream = defaultInfoStream; - termIndexInterval = conf.getTermIndexInterval(); mergePolicy = conf.getMergePolicy(); mergePolicy.setIndexWriter(this); mergeScheduler = conf.getMergeScheduler(); - mergedSegmentWarmer = conf.getMergedSegmentWarmer(); codecs = conf.getCodecProvider(); bufferedDeletesStream = new BufferedDeletesStream(messageID); @@ -791,7 +786,7 @@ setRollbackSegmentInfos(segmentInfos); - docWriter = new DocumentsWriter(directory, this, conf.getIndexingChain(), conf.getMaxThreadStates(), getCurrentFieldInfos(), bufferedDeletesStream); + docWriter = new DocumentsWriter(config, directory, this, conf.getIndexingChain(), conf.getMaxThreadStates(), getCurrentFieldInfos(), bufferedDeletesStream); docWriter.setInfoStream(infoStream); // Default deleter (for backwards compatibility) is @@ -809,10 +804,6 @@ segmentInfos.changed(); } - docWriter.setRAMBufferSizeMB(conf.getRAMBufferSizeMB()); - docWriter.setMaxBufferedDocs(conf.getMaxBufferedDocs()); - pushMaxBufferedDocs(); - if (infoStream != null) { message("init: create=" + create); messageState(); @@ -881,38 +872,20 @@ } /** - * Returns the {@link IndexWriterConfig} that was passed to - * {@link #IndexWriter(Directory, IndexWriterConfig)}. This allows querying - * IndexWriter's settings. + * Returns the private {@link IndexWriterConfig}, cloned + * from the {@link IndexWriterConfig} passed to + * {@link #IndexWriter(Directory, IndexWriterConfig)}. *

- * NOTE: setting any parameter on the returned instance has not effect - * on the IndexWriter instance. If you need to change those settings after - * IndexWriter has been created, you need to instantiate a new IndexWriter. + * NOTE: some settings may be changed on the + * returned {@link IndexWriterConfig}, and will take + * effect in the current IndexWriter instance. See the + * javadocs for the specific setters in {@link + * IndexWriterConfig} for details. */ public IndexWriterConfig getConfig() { return config; } - /** - * If we are flushing by doc count (not by RAM usage), and - * using LogDocMergePolicy then push maxBufferedDocs down - * as its minMergeDocs, to keep backwards compatibility. - */ - private void pushMaxBufferedDocs() { - if (docWriter.getMaxBufferedDocs() != IndexWriterConfig.DISABLE_AUTO_FLUSH) { - final MergePolicy mp = mergePolicy; - if (mp instanceof LogDocMergePolicy) { - LogDocMergePolicy lmp = (LogDocMergePolicy) mp; - final int maxBufferedDocs = docWriter.getMaxBufferedDocs(); - if (lmp.getMinMergeDocs() != maxBufferedDocs) { - if (infoStream != null) - message("now push maxBufferedDocs " + maxBufferedDocs + " to LogDocMergePolicy"); - lmp.setMinMergeDocs(maxBufferedDocs); - } - } - } - } - /** If non-null, this will be the default infoStream used * by a newly instantiated IndexWriter. * @see #setInfoStream @@ -1476,8 +1449,8 @@ /** If non-null, information about merges will be printed to this. */ - private PrintStream infoStream = null; - private static PrintStream defaultInfoStream = null; + private volatile PrintStream infoStream; + private static volatile PrintStream defaultInfoStream; /** * Requests an "optimize" operation on an index, priming the index @@ -2270,7 +2243,7 @@ try { String mergedName = newSegmentName(); - SegmentMerger merger = new SegmentMerger(directory, termIndexInterval, + SegmentMerger merger = new SegmentMerger(directory, config.getTermIndexInterval(), mergedName, null, codecs, payloadProcessorProvider, ((FieldInfos) docWriter.getFieldInfos().clone())); @@ -3163,7 +3136,7 @@ SegmentInfos sourceSegments = merge.segments; - SegmentMerger merger = new SegmentMerger(directory, termIndexInterval, mergedName, merge, + SegmentMerger merger = new SegmentMerger(directory, config.getTermIndexInterval(), mergedName, merge, codecs, payloadProcessorProvider, ((FieldInfos) docWriter.getFieldInfos().clone())); @@ -3292,6 +3265,8 @@ merge.info.setUseCompoundFile(true); } + final IndexReaderWarmer mergedSegmentWarmer = config.getMergedSegmentWarmer(); + final int termsIndexDivisor; final boolean loadDocStores; @@ -3572,8 +3547,6 @@ public abstract void warm(IndexReader reader) throws IOException; } - private IndexReaderWarmer mergedSegmentWarmer; - private void handleOOM(OutOfMemoryError oom, String location) { if (infoStream != null) { message("hit OutOfMemoryError inside " + location); Index: lucene/src/java/org/apache/lucene/index/IndexWriterConfig.java --- lucene/src/java/org/apache/lucene/index/IndexWriterConfig.java Mon Mar 14 13:57:08 2011 -0400 +++ lucene/src/java/org/apache/lucene/index/IndexWriterConfig.java Mon Mar 14 17:53:45 2011 -0400 @@ -26,12 +26,16 @@ import org.apache.lucene.util.Version; /** - * Holds all the configuration of {@link IndexWriter}. This object is only used - * while constructing a new IndexWriter. Those settings cannot be changed - * afterwards, except instantiating a new IndexWriter. + * Holds all the configuration of {@link IndexWriter}. You + * should instantiate this class, call the setters to set + * your configuration, then pass it to {@link IndexWriter}. + * Note that {@link IndexWriter} makes a private clone; if + * you need to subsequently change settings use {@link + * IndexWriter#getConfig}. + * *

* All setter methods return {@link IndexWriterConfig} to allow chaining - * settings conveniently. Thus someone can do: + * settings conveniently, for example: * * 

  * IndexWriterConfig conf = new IndexWriterConfig(analyzer);
@@ -108,24 +112,24 @@
     return WRITE_LOCK_TIMEOUT;
   }
 
-  private Analyzer analyzer;
-  private IndexDeletionPolicy delPolicy;
-  private IndexCommit commit;
-  private OpenMode openMode;
-  private SimilarityProvider similarityProvider;
-  private int termIndexInterval; // TODO: this should be private to the codec, not settable here
-  private MergeScheduler mergeScheduler;
-  private long writeLockTimeout;
-  private int maxBufferedDeleteTerms;
-  private double ramBufferSizeMB;
-  private int maxBufferedDocs;
-  private IndexingChain indexingChain;
-  private IndexReaderWarmer mergedSegmentWarmer;
-  private CodecProvider codecProvider;
-  private MergePolicy mergePolicy;
-  private int maxThreadStates;
-  private boolean readerPooling;
-  private int readerTermsIndexDivisor;
+  private final Analyzer analyzer;
+  private volatile IndexDeletionPolicy delPolicy;
+  private volatile IndexCommit commit;
+  private volatile OpenMode openMode;
+  private volatile SimilarityProvider similarityProvider;
+  private volatile int termIndexInterval; // TODO: this should be private to the codec, not settable here
+  private volatile MergeScheduler mergeScheduler;
+  private volatile long writeLockTimeout;
+  private volatile int maxBufferedDeleteTerms;
+  private volatile double ramBufferSizeMB;
+  private volatile int maxBufferedDocs;
+  private volatile IndexingChain indexingChain;
+  private volatile IndexReaderWarmer mergedSegmentWarmer;
+  private volatile CodecProvider codecProvider;
+  private volatile MergePolicy mergePolicy;
+  private volatile int maxThreadStates;
+  private volatile boolean readerPooling;
+  private volatile int readerTermsIndexDivisor;
   
   // required for clone
   private Version matchVersion;
@@ -176,7 +180,9 @@
     return analyzer;
   }
 
-  /** Specifies {@link OpenMode} of that index. */
+  /** Specifies {@link OpenMode} of that index.
+   * 
+   * 
Only takes effect when IndexWriter is first created. */
   public IndexWriterConfig setOpenMode(OpenMode openMode) {
     this.openMode = openMode;
     return this;
@@ -201,6 +207,8 @@
    * 

    * NOTE: the deletion policy cannot be null. If null is
    * passed, the deletion policy will be set to the default.
+   *
+   * 
Only takes effect when IndexWriter is first created. 
    */
   public IndexWriterConfig setIndexDeletionPolicy(IndexDeletionPolicy delPolicy) {
     this.delPolicy = delPolicy == null ? new KeepOnlyLastCommitDeletionPolicy() : delPolicy;
@@ -219,7 +227,8 @@
   /**
    * Expert: allows to open a certain commit point. The default is null which
    * opens the latest commit point.
-   */
+   *
+   * 
Only takes effect when IndexWriter is first created. */
   public IndexWriterConfig setIndexCommit(IndexCommit commit) {
     this.commit = commit;
     return this;
@@ -239,7 +248,8 @@
    * 

    * NOTE: the similarity provider cannot be null. If null is passed,
    * the similarity provider will be set to the default implementation (unspecified).
-   */
+   *
+   * 
Only takes effect when IndexWriter is first created. */
   public IndexWriterConfig setSimilarityProvider(SimilarityProvider similarityProvider) {
     this.similarityProvider = similarityProvider == null ? IndexSearcher.getDefaultSimilarityProvider() : similarityProvider;
     return this;
@@ -274,7 +284,9 @@
    * must be scanned for each random term access.
    * 
    * @see #DEFAULT_TERM_INDEX_INTERVAL
-   */
+   *
+   * 
Takes effect immediately, but only applies to newly
+   *  flushed/merged segments. */
   public IndexWriterConfig setTermIndexInterval(int interval) { // TODO: this should be private to the codec, not settable here
     this.termIndexInterval = interval;
     return this;
@@ -295,7 +307,8 @@
    * 

    * NOTE: the merge scheduler cannot be null. If null is
    * passed, the merge scheduler will be set to the default.
-   */
+   *
+   * 
Only takes effect when IndexWriter is first created. */
   public IndexWriterConfig setMergeScheduler(MergeScheduler mergeScheduler) {
     this.mergeScheduler = mergeScheduler == null ? new ConcurrentMergeScheduler() : mergeScheduler;
     return this;
@@ -313,7 +326,8 @@
    * Sets the maximum time to wait for a write lock (in milliseconds) for this
    * instance. You can change the default value for all instances by calling
    * {@link #setDefaultWriteLockTimeout(long)}.
-   */
+   *
+   * 
Only takes effect when IndexWriter is first created. */
   public IndexWriterConfig setWriteLockTimeout(long writeLockTimeout) {
     this.writeLockTimeout = writeLockTimeout;
     return this;
@@ -339,6 +353,9 @@
    * @throws IllegalArgumentException if maxBufferedDeleteTerms
    * is enabled but smaller than 1
    * @see #setRAMBufferSizeMB
+   *
+   * 
Takes effect immediately, but only the next time a
+   * document is added, updated or deleted.
    */
   public IndexWriterConfig setMaxBufferedDeleteTerms(int maxBufferedDeleteTerms) {
     if (maxBufferedDeleteTerms != DISABLE_AUTO_FLUSH
@@ -391,6 +408,9 @@
    * 

    * The default value is {@link #DEFAULT_RAM_BUFFER_SIZE_MB}.
    * 
+   * 
Takes effect immediately, but only the next time a
+   * document is added, updated or deleted.
+   *
    * @throws IllegalArgumentException
    *           if ramBufferSize is enabled but non-positive, or it disables
    *           ramBufferSize when maxBufferedDocs is already disabled
@@ -430,6 +450,9 @@
    * 

    * Disabled by default (writer flushes by RAM usage).
    * 
+   * 
Takes effect immediately, but only the next time a
+   * document is added, updated or deleted.
+   *
    * @see #setRAMBufferSizeMB(double)
    * 
    * @throws IllegalArgumentException
@@ -458,7 +481,9 @@
     return maxBufferedDocs;
   }
 
-  /** Set the merged segment warmer. See {@link IndexReaderWarmer}. */
+  /** Set the merged segment warmer. See {@link IndexReaderWarmer}.
+   *
+   * 
Takes effect on the next merge. */
   public IndexWriterConfig setMergedSegmentWarmer(IndexReaderWarmer mergeSegmentWarmer) {
     this.mergedSegmentWarmer = mergeSegmentWarmer;
     return this;
@@ -475,13 +500,16 @@
    * and return a {@link MergePolicy.MergeSpecification} describing the merges.
    * It also selects merges to do for optimize(). (The default is
    * {@link LogByteSizeMergePolicy}.
-   */
+   *
+   * 
Only takes effect when IndexWriter is first created. */
   public IndexWriterConfig setMergePolicy(MergePolicy mergePolicy) {
     this.mergePolicy = mergePolicy == null ? new LogByteSizeMergePolicy() : mergePolicy;
     return this;
   }
 
-  /** Set the CodecProvider. See {@link CodecProvider}. */
+  /** Set the CodecProvider. See {@link CodecProvider}.
+   *
+   * 
Only takes effect when IndexWriter is first created. */
   public IndexWriterConfig setCodecProvider(CodecProvider codecProvider) {
     this.codecProvider = codecProvider;
     return this;
@@ -507,7 +535,8 @@
    * at once in IndexWriter. Values < 1 are invalid and if passed
    * maxThreadStates will be set to
    * {@link #DEFAULT_MAX_THREAD_STATES}.
-   */
+   *
+   * 
Only takes effect when IndexWriter is first created. */
   public IndexWriterConfig setMaxThreadStates(int maxThreadStates) {
     this.maxThreadStates = maxThreadStates < 1 ? DEFAULT_MAX_THREAD_STATES : maxThreadStates;
     return this;
@@ -526,7 +555,9 @@
    *  This method lets you enable pooling without getting a
    *  near-real-time reader.  NOTE: if you set this to
    *  false, IndexWriter will still pool readers once
-   *  {@link IndexWriter#getReader} is called. */
+   *  {@link IndexWriter#getReader} is called.
+   *
+   * 
Only takes effect when IndexWriter is first created. */
   public IndexWriterConfig setReaderPooling(boolean readerPooling) {
     this.readerPooling = readerPooling;
     return this;
@@ -538,7 +569,9 @@
     return readerPooling;
   }
 
-  /** Expert: sets the {@link DocConsumer} chain to be used to process documents. */
+  /** Expert: sets the {@link DocConsumer} chain to be used to process documents.
+   *
+   * 
Only takes effect when IndexWriter is first created. */
   IndexWriterConfig setIndexingChain(IndexingChain indexingChain) {
     this.indexingChain = indexingChain == null ? DocumentsWriter.defaultIndexingChain : indexingChain;
     return this;
@@ -555,7 +588,10 @@
    *  IndexWriter#getReader}. If you pass -1, the terms index 
    *  won't be loaded by the readers. This is only useful in 
    *  advanced situations when you will only .next() through 
-   *  all terms; attempts to seek will hit an exception. */
+   *  all terms; attempts to seek will hit an exception.
+   *
+   * 
Takes effect immediately, but only applies to
+   * readers opened after this call */
   public IndexWriterConfig setReaderTermsIndexDivisor(int divisor) {
     if (divisor <= 0 && divisor != -1) {
       throw new IllegalArgumentException("divisor must be >= 1, or -1 (got " + divisor + ")");
Index: lucene/src/test/org/apache/lucene/index/TestIndexWriter.java
--- lucene/src/test/org/apache/lucene/index/TestIndexWriter.java	Mon Mar 14 13:57:08 2011 -0400
+++ lucene/src/test/org/apache/lucene/index/TestIndexWriter.java	Mon Mar 14 17:53:45 2011 -0400
@@ -681,6 +681,122 @@
       dir.close();
     }
 
+    // Make sure it's OK to change RAM buffer size and
+    // maxBufferedDocs in a write session
+    public void testChangingRAMBuffer() throws IOException {
+      RAMDirectory dir = new RAMDirectory();      
+      IndexWriter writer  = new IndexWriter(dir, newIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer()));
+      writer.getConfig().setMaxBufferedDocs(10);
+      writer.getConfig().setRAMBufferSizeMB(IndexWriterConfig.DISABLE_AUTO_FLUSH);
+
+      int lastFlushCount = -1;
+      for(int j=1;j<52;j++) {
+        Document doc = new Document();
+        doc.add(new Field("field", "aaa" + j, Field.Store.YES, Field.Index.ANALYZED));
+        writer.addDocument(doc);
+        _TestUtil.syncConcurrentMerges(writer);
+        int flushCount = writer.getFlushCount();
+        if (j == 1)
+          lastFlushCount = flushCount;
+        else if (j < 10)
+          // No new files should be created
+          assertEquals(flushCount, lastFlushCount);
+        else if (10 == j) {
+          assertTrue(flushCount > lastFlushCount);
+          lastFlushCount = flushCount;
+          writer.getConfig().setRAMBufferSizeMB(0.000001);
+          writer.getConfig().setMaxBufferedDocs(IndexWriterConfig.DISABLE_AUTO_FLUSH);
+        } else if (j < 20) {
+          assertTrue(flushCount > lastFlushCount);
+          lastFlushCount = flushCount;
+        } else if (20 == j) {
+          writer.getConfig().setRAMBufferSizeMB(16);
+          writer.getConfig().setMaxBufferedDocs(IndexWriterConfig.DISABLE_AUTO_FLUSH);
+          lastFlushCount = flushCount;
+        } else if (j < 30) {
+          assertEquals(flushCount, lastFlushCount);
+        } else if (30 == j) {
+          writer.getConfig().setRAMBufferSizeMB(0.000001);
+          writer.getConfig().setMaxBufferedDocs(IndexWriterConfig.DISABLE_AUTO_FLUSH);
+        } else if (j < 40) {
+          assertTrue(flushCount> lastFlushCount);
+          lastFlushCount = flushCount;
+        } else if (40 == j) {
+          writer.getConfig().setMaxBufferedDocs(10);
+          writer.getConfig().setRAMBufferSizeMB(IndexWriterConfig.DISABLE_AUTO_FLUSH);
+          lastFlushCount = flushCount;
+        } else if (j < 50) {
+          assertEquals(flushCount, lastFlushCount);
+          writer.getConfig().setMaxBufferedDocs(10);
+          writer.getConfig().setRAMBufferSizeMB(IndexWriterConfig.DISABLE_AUTO_FLUSH);
+        } else if (50 == j) {
+          assertTrue(flushCount > lastFlushCount);
+        }
+      }
+      writer.close();
+      dir.close();
+    }
+
+    public void testChangingRAMBuffer2() throws IOException {
+      RAMDirectory dir = new RAMDirectory();      
+      IndexWriter writer  = new IndexWriter(dir, newIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer()));
+      writer.getConfig().setMaxBufferedDocs(10);
+      writer.getConfig().setMaxBufferedDeleteTerms(10);
+      writer.getConfig().setRAMBufferSizeMB(IndexWriterConfig.DISABLE_AUTO_FLUSH);
+
+      for(int j=1;j<52;j++) {
+        Document doc = new Document();
+        doc.add(new Field("field", "aaa" + j, Field.Store.YES, Field.Index.ANALYZED));
+        writer.addDocument(doc);
+      }
+      
+      int lastFlushCount = -1;
+      for(int j=1;j<52;j++) {
+        writer.deleteDocuments(new Term("field", "aaa" + j));
+        _TestUtil.syncConcurrentMerges(writer);
+        int flushCount = writer.getFlushCount();
+        if (j == 1)
+          lastFlushCount = flushCount;
+        else if (j < 10) {
+          // No new files should be created
+          assertEquals(flushCount, lastFlushCount);
+        } else if (10 == j) {
+          assertTrue(flushCount > lastFlushCount);
+          lastFlushCount = flushCount;
+          writer.getConfig().setRAMBufferSizeMB(0.000001);
+          writer.getConfig().setMaxBufferedDeleteTerms(1);
+        } else if (j < 20) {
+          assertTrue(flushCount > lastFlushCount);
+          lastFlushCount = flushCount;
+        } else if (20 == j) {
+          writer.getConfig().setRAMBufferSizeMB(16);
+          writer.getConfig().setMaxBufferedDeleteTerms(IndexWriterConfig.DISABLE_AUTO_FLUSH);
+          lastFlushCount = flushCount;
+        } else if (j < 30) {
+          assertEquals(flushCount, lastFlushCount);
+        } else if (30 == j) {
+          writer.getConfig().setRAMBufferSizeMB(0.000001);
+          writer.getConfig().setMaxBufferedDeleteTerms(IndexWriterConfig.DISABLE_AUTO_FLUSH);
+          writer.getConfig().setMaxBufferedDeleteTerms(1);
+        } else if (j < 40) {
+          assertTrue(flushCount> lastFlushCount);
+          lastFlushCount = flushCount;
+        } else if (40 == j) {
+          writer.getConfig().setMaxBufferedDeleteTerms(10);
+          writer.getConfig().setRAMBufferSizeMB(IndexWriterConfig.DISABLE_AUTO_FLUSH);
+          lastFlushCount = flushCount;
+        } else if (j < 50) {
+          assertEquals(flushCount, lastFlushCount);
+          writer.getConfig().setMaxBufferedDeleteTerms(10);
+          writer.getConfig().setRAMBufferSizeMB(IndexWriterConfig.DISABLE_AUTO_FLUSH);
+        } else if (50 == j) {
+          assertTrue(flushCount > lastFlushCount);
+        }
+      }
+      writer.close();
+      dir.close();
+    }
+
     public void testDiverseDocs() throws IOException {
       MockDirectoryWrapper dir = newDirectory();      
       IndexWriter writer  = new IndexWriter(dir, newIndexWriterConfig( TEST_VERSION_CURRENT, new MockAnalyzer()).setRAMBufferSizeMB(0.5));