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Lucene example source code file (TestIndexWriterMergePolicy.java)

This example Lucene source code file (TestIndexWriterMergePolicy.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

directory, document, indexwriter, indexwriter, io, ioexception, ioexception, logdocmergepolicy, logdocmergepolicy, logmergepolicy, mockanalyzer, serialmergescheduler, term, test_version_current, test_version_current

The Lucene TestIndexWriterMergePolicy.java source code

package org.apache.lucene.index;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;

import org.apache.lucene.analysis.MockAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexWriterConfig.OpenMode;
import org.apache.lucene.store.Directory;

import org.apache.lucene.util.LuceneTestCase;

public class TestIndexWriterMergePolicy extends LuceneTestCase {
  
  // Test the normal case
  public void testNormalCase() throws IOException {
    Directory dir = newDirectory();

    IndexWriter writer = new IndexWriter(dir, newIndexWriterConfig(
        TEST_VERSION_CURRENT, new MockAnalyzer(random))
        .setMaxBufferedDocs(10).setMergePolicy(new LogDocMergePolicy()));

    for (int i = 0; i < 100; i++) {
      addDoc(writer);
      checkInvariants(writer);
    }

    writer.close();
    dir.close();
  }

  // Test to see if there is over merge
  public void testNoOverMerge() throws IOException {
    Directory dir = newDirectory();

    IndexWriter writer = new IndexWriter(dir, newIndexWriterConfig(
        TEST_VERSION_CURRENT, new MockAnalyzer(random))
        .setMaxBufferedDocs(10).setMergePolicy(new LogDocMergePolicy()));

    boolean noOverMerge = false;
    for (int i = 0; i < 100; i++) {
      addDoc(writer);
      checkInvariants(writer);
      if (writer.getNumBufferedDocuments() + writer.getSegmentCount() >= 18) {
        noOverMerge = true;
      }
    }
    assertTrue(noOverMerge);

    writer.close();
    dir.close();
  }

  // Test the case where flush is forced after every addDoc
  public void testForceFlush() throws IOException {
    Directory dir = newDirectory();

    LogDocMergePolicy mp = new LogDocMergePolicy();
    mp.setMinMergeDocs(100);
    mp.setMergeFactor(10);
    IndexWriter writer = new IndexWriter(dir, newIndexWriterConfig(
        TEST_VERSION_CURRENT, new MockAnalyzer(random))
        .setMaxBufferedDocs(10).setMergePolicy(mp));

    for (int i = 0; i < 100; i++) {
      addDoc(writer);
      writer.close();

      mp = new LogDocMergePolicy();
      mp.setMergeFactor(10);
      writer = new IndexWriter(dir, newIndexWriterConfig( TEST_VERSION_CURRENT,
          new MockAnalyzer(random)).setOpenMode(
          OpenMode.APPEND).setMaxBufferedDocs(10).setMergePolicy(mp));
      mp.setMinMergeDocs(100);
      checkInvariants(writer);
    }

    writer.close();
    dir.close();
  }

  // Test the case where mergeFactor changes
  public void testMergeFactorChange() throws IOException {
    Directory dir = newDirectory();

    IndexWriter writer = new IndexWriter(
        dir,
        newIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(random)).
            setMaxBufferedDocs(10).
            setMergePolicy(newLogMergePolicy()).
            setMergeScheduler(new SerialMergeScheduler())
    );

    writer.setInfoStream(VERBOSE ? System.out : null);

    for (int i = 0; i < 250; i++) {
      addDoc(writer);
      checkInvariants(writer);
    }

    ((LogMergePolicy) writer.getConfig().getMergePolicy()).setMergeFactor(5);

    // merge policy only fixes segments on levels where merges
    // have been triggered, so check invariants after all adds
    for (int i = 0; i < 10; i++) {
      addDoc(writer);
    }
    checkInvariants(writer);

    writer.close();
    dir.close();
  }

  // Test the case where both mergeFactor and maxBufferedDocs change
  public void testMaxBufferedDocsChange() throws IOException {
    Directory dir = newDirectory();

    IndexWriter writer = new IndexWriter(dir, newIndexWriterConfig(
        TEST_VERSION_CURRENT, new MockAnalyzer(random))
        .setMaxBufferedDocs(101).setMergePolicy(new LogDocMergePolicy())
        .setMergeScheduler(new SerialMergeScheduler()));

    // leftmost* segment has 1 doc
    // rightmost* segment has 100 docs
    for (int i = 1; i <= 100; i++) {
      for (int j = 0; j < i; j++) {
        addDoc(writer);
        checkInvariants(writer);
      }
      writer.close();

      writer = new IndexWriter(dir, newIndexWriterConfig( TEST_VERSION_CURRENT,
          new MockAnalyzer(random)).setOpenMode(
          OpenMode.APPEND).setMaxBufferedDocs(101).setMergePolicy(new LogDocMergePolicy())
                          .setMergeScheduler(new SerialMergeScheduler()));
    }

    writer.close();
    LogDocMergePolicy ldmp = new LogDocMergePolicy();
    ldmp.setMergeFactor(10);
    writer = new IndexWriter(dir, newIndexWriterConfig( TEST_VERSION_CURRENT,
        new MockAnalyzer(random)).setOpenMode(
        OpenMode.APPEND).setMaxBufferedDocs(10).setMergePolicy(ldmp).setMergeScheduler(new SerialMergeScheduler()));

    // merge policy only fixes segments on levels where merges
    // have been triggered, so check invariants after all adds
    for (int i = 0; i < 100; i++) {
      addDoc(writer);
    }
    checkInvariants(writer);

    for (int i = 100; i < 1000; i++) {
      addDoc(writer);
    }
    writer.commit();
    writer.waitForMerges();
    writer.commit();
    checkInvariants(writer);

    writer.close();
    dir.close();
  }

  // Test the case where a merge results in no doc at all
  public void testMergeDocCount0() throws IOException {
    Directory dir = newDirectory();

    LogDocMergePolicy ldmp = new LogDocMergePolicy();
    ldmp.setMergeFactor(100);
    IndexWriter writer = new IndexWriter(dir, newIndexWriterConfig(
        TEST_VERSION_CURRENT, new MockAnalyzer(random))
        .setMaxBufferedDocs(10).setMergePolicy(ldmp));

    for (int i = 0; i < 250; i++) {
      addDoc(writer);
      checkInvariants(writer);
    }
    writer.close();

    IndexReader reader = IndexReader.open(dir, false);
    reader.deleteDocuments(new Term("content", "aaa"));
    reader.close();

    ldmp = new LogDocMergePolicy();
    ldmp.setMergeFactor(5);
    writer = new IndexWriter(dir, newIndexWriterConfig( TEST_VERSION_CURRENT,
        new MockAnalyzer(random)).setOpenMode(
        OpenMode.APPEND).setMaxBufferedDocs(10).setMergePolicy(ldmp).setMergeScheduler(new ConcurrentMergeScheduler()));

    // merge factor is changed, so check invariants after all adds
    for (int i = 0; i < 10; i++) {
      addDoc(writer);
    }
    writer.commit();
    writer.waitForMerges();
    writer.commit();
    checkInvariants(writer);
    assertEquals(10, writer.maxDoc());

    writer.close();
    dir.close();
  }

  private void addDoc(IndexWriter writer) throws IOException {
    Document doc = new Document();
    doc.add(newField("content", "aaa", Field.Store.NO, Field.Index.ANALYZED));
    writer.addDocument(doc);
  }

  private void checkInvariants(IndexWriter writer) throws IOException {
    writer.waitForMerges();
    int maxBufferedDocs = writer.getConfig().getMaxBufferedDocs();
    int mergeFactor = ((LogMergePolicy) writer.getConfig().getMergePolicy()).getMergeFactor();
    int maxMergeDocs = ((LogMergePolicy) writer.getConfig().getMergePolicy()).getMaxMergeDocs();

    int ramSegmentCount = writer.getNumBufferedDocuments();
    assertTrue(ramSegmentCount < maxBufferedDocs);

    int lowerBound = -1;
    int upperBound = maxBufferedDocs;
    int numSegments = 0;

    int segmentCount = writer.getSegmentCount();
    for (int i = segmentCount - 1; i >= 0; i--) {
      int docCount = writer.getDocCount(i);
      assertTrue("docCount=" + docCount + " lowerBound=" + lowerBound + " upperBound=" + upperBound + " i=" + i + " segmentCount=" + segmentCount + " index=" + writer.segString() + " config=" + writer.getConfig(), docCount > lowerBound);

      if (docCount <= upperBound) {
        numSegments++;
      } else {
        if (upperBound * mergeFactor <= maxMergeDocs) {
          assertTrue("maxMergeDocs=" + maxMergeDocs + "; numSegments=" + numSegments + "; upperBound=" + upperBound + "; mergeFactor=" + mergeFactor + "; segs=" + writer.segString() + " config=" + writer.getConfig(), numSegments < mergeFactor);
        }

        do {
          lowerBound = upperBound;
          upperBound *= mergeFactor;
        } while (docCount > upperBound);
        numSegments = 1;
      }
    }
    if (upperBound * mergeFactor <= maxMergeDocs) {
      assertTrue(numSegments < mergeFactor);
    }
  }
}

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