LUCENE-1959 Add MultiPassIndexSplitter.

git-svn-id: https://svn.apache.org/repos/asf/lucene/java/trunk@824798 13f79535-47bb-0310-9956-ffa450edef68

contrib/CHANGES.txt

@@ -41,10 +41,13 @@ New features
    segment merges to give better search performance in a mixed
    indexing/searching environment.  (John Wang via Mike McCandless)
 
- * LUCENE-1959: Add IndexSplitter tool, to copy specific segments out
-   of the index into a new index.  It can also list the segments in
-   the index, and delete specified segments.  (Jason Rutherglen via
-   Mike McCandless)
+ * LUCENE-1959: Add index splitting tools. The IndexSplitter tool works
+   on multi-segment (non optimized) indexes and it can copy specific
+   segments out of the index into a new index.  It can also list the
+   segments in the index, and delete specified segments.  (Jason Rutherglen via
+   Mike McCandless). MultiPassIndexSplitter can split any index into
+   any number of output parts, at the cost of doing multiple passes over
+   the input index. (Andrzej Bialecki)
 
 Optimizations
 

contrib/misc/src/java/org/apache/lucene/index/MultiPassIndexSplitter.java

@@ -0,0 +1,236 @@
+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.File;
+import java.io.IOException;
+import java.util.ArrayList;
+
+import org.apache.lucene.analysis.WhitespaceAnalyzer;
+import org.apache.lucene.index.IndexWriter.MaxFieldLength;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.FSDirectory;
+import org.apache.lucene.util.OpenBitSet;
+
+/**
+ * This tool splits input index into multiple equal parts. The method employed
+ * here uses {@link IndexWriter#addIndexes(IndexReader[])} where the input data
+ * comes from the input index with artificially applied deletes to the document
+ * id-s that fall outside the selected partition.
+ * <p>Note 1: Deletes are only applied to a buffered list of deleted docs and
+ * don't affect the source index - this tool works also with read-only indexes.
+ * <p>Note 2: the disadvantage of this tool is that source index needs to be
+ * read as many times as there are parts to be created, hence the name of this
+ * tool.
+ */
+public class MultiPassIndexSplitter {
+  
+  /**
+   * Split source index into multiple parts.
+   * @param input source index, can be read-only, can have deletions, can have
+   * multiple segments (or multiple readers).
+   * @param outputs list of directories where the output parts will be stored.
+   * @param seq if true, then the source index will be split into equal
+   * increasing ranges of document id-s. If false, source document id-s will be
+   * assigned in a deterministic round-robin fashion to one of the output splits.
+   * @throws IOException
+   */
+  public void split(IndexReader input, Directory[] outputs, boolean seq) throws IOException {
+    if (outputs == null || outputs.length < 2) {
+      throw new IOException("Invalid number of outputs.");
+    }
+    if (input == null || input.numDocs() < 2) {
+      throw new IOException("Not enough documents for splitting");
+    }
+    int numParts = outputs.length;
+    // wrap a potentially read-only input
+    // this way we don't have to preserve original deletions because neither
+    // deleteDocument(int) or undeleteAll() is applied to the wrapped input index.
+    input = new FakeDeleteIndexReader(input);
+    int maxDoc = input.maxDoc();
+    int partLen = maxDoc / numParts;
+    for (int i = 0; i < numParts; i++) {
+      input.undeleteAll();
+      if (seq) { // sequential range
+        int lo = partLen * i;
+        int hi = lo + partLen;
+        // below range
+        for (int j = 0; j < lo; j++) {
+          input.deleteDocument(j);
+        }
+        // above range - last part collects all id-s that remained due to
+        // integer rounding errors
+        if (i < numParts - 1) {
+          for (int j = hi; j < maxDoc; j++) {
+            input.deleteDocument(j);
+          }
+        }
+      } else {
+        // round-robin
+        for (int j = 0; j < maxDoc; j++) {
+          if ((j + numParts - i) % numParts != 0) {
+            input.deleteDocument(j);
+          }
+        }
+      }
+      IndexWriter w = new IndexWriter(outputs[i], new WhitespaceAnalyzer(),
+              true, MaxFieldLength.UNLIMITED);
+      System.err.println("Writing part " + (i + 1) + " ...");
+      w.addIndexes(new IndexReader[]{input});
+      w.close();
+    }
+    System.err.println("Done.");
+  }
+  
+  public static void main(String[] args) throws Exception {
+    if (args.length < 5) {
+      System.err.println("Usage: MultiPassIndexSplitter -out <outputDir> -num <numParts> [-seq] <inputIndex1> [<inputIndex2 ...]");
+      System.err.println("\tinputIndex\tpath to input index, multiple values are ok");
+      System.err.println("\t-out ouputDir\tpath to output directory to contain partial indexes");
+      System.err.println("\t-num numParts\tnumber of parts to produce");
+      System.err.println("\t-seq\tsequential docid-range split (default is round-robin)");
+      System.exit(-1);
+    }
+    ArrayList<IndexReader> indexes = new ArrayList<IndexReader>();
+    String outDir = null;
+    int numParts = -1;
+    boolean seq = false;
+    for (int i = 0; i < args.length; i++) {
+      if (args[i].equals("-out")) {
+        outDir = args[++i];
+      } else if (args[i].equals("-num")) {
+        numParts = Integer.parseInt(args[++i]);
+      } else if (args[i].equals("-seq")) {
+        seq = true;
+      } else {
+        File file = new File(args[i]);
+        if (!file.exists() || !file.isDirectory()) {
+          System.err.println("Invalid input path - skipping: " + file);
+          continue;
+        }
+        Directory dir = FSDirectory.open(new File(args[i]));
+        try {
+          if (!IndexReader.indexExists(dir)) {
+            System.err.println("Invalid input index - skipping: " + file);
+            continue;
+          }
+        } catch (Exception e) {
+          System.err.println("Invalid input index - skipping: " + file);
+          continue;
+        }
+        indexes.add(IndexReader.open(dir, true));
+      }
+    }
+    if (outDir == null) {
+      throw new Exception("Required argument missing: -out outputDir");
+    }
+    if (numParts < 2) {
+      throw new Exception("Invalid value of required argument: -num numParts");
+    }
+    if (indexes.size() == 0) {
+      throw new Exception("No input indexes to process");
+    }
+    File out = new File(outDir);
+    if (!out.mkdirs()) {
+      throw new Exception("Can't create output directory: " + out);
+    }
+    Directory[] dirs = new Directory[numParts];
+    for (int i = 0; i < numParts; i++) {
+      dirs[i] = FSDirectory.open(new File(out, "part-" + i));
+    }
+    MultiPassIndexSplitter splitter = new MultiPassIndexSplitter();
+    IndexReader input;
+    if (indexes.size() == 1) {
+      input = indexes.get(0);
+    } else {
+      input = new MultiReader((IndexReader[])indexes.toArray(new IndexReader[indexes.size()]));
+    }
+    splitter.split(input, dirs, seq);
+  }
+  
+  /**
+   * This class pretends that it can write deletions to the underlying index.
+   * Instead, deletions are buffered in a bitset and overlaid with the original
+   * list of deletions.
+   */
+  public static class FakeDeleteIndexReader extends FilterIndexReader {
+    OpenBitSet dels;
+    OpenBitSet oldDels = null;
+
+    public FakeDeleteIndexReader(IndexReader in) {
+      super(in);
+      dels = new OpenBitSet(in.maxDoc());
+      if (in.hasDeletions()) {
+        oldDels = new OpenBitSet(in.maxDoc());
+        for (int i = 0; i < in.maxDoc(); i++) {
+          if (in.isDeleted(i)) oldDels.set(i);
+        }
+        dels.or(oldDels);
+      }
+    }
+
+    @Override
+    public int numDocs() {
+      return in.maxDoc() - (int)dels.cardinality();
+    }
+
+    /**
+     * Just removes our overlaid deletions - does not undelete the original
+     * deletions.
+     */
+    @Override
+    protected void doUndeleteAll() throws CorruptIndexException, IOException {
+      dels = new OpenBitSet(in.maxDoc());
+      if (oldDels != null) {
+        dels.or(oldDels);
+      }
+    }
+
+    @Override
+    protected void doDelete(int n) throws CorruptIndexException, IOException {
+      dels.set(n);
+    }
+
+    @Override
+    public boolean hasDeletions() {
+      return !dels.isEmpty();
+    }
+
+    @Override
+    public boolean isDeleted(int n) {
+      return dels.get(n);
+    }
+
+    @Override
+    public TermPositions termPositions() throws IOException {
+      return new FilterTermPositions(in.termPositions()) {
+
+        @Override
+        public boolean next() throws IOException {
+          boolean res;
+          while ((res = super.next())) {
+            if (!dels.get(doc())) {
+              break;
+            }
+          }
+          return res;
+        }        
+      };
+    }
+  }
+}

contrib/misc/src/test/org/apache/lucene/index/TestMultiPassIndexSplitter.java

@@ -0,0 +1,127 @@
+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 org.apache.lucene.analysis.WhitespaceAnalyzer;
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.Field;
+import org.apache.lucene.index.IndexWriter.MaxFieldLength;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.RAMDirectory;
+
+import junit.framework.TestCase;
+
+public class TestMultiPassIndexSplitter extends TestCase {
+  IndexReader input;
+  int NUM_DOCS = 11;
+
+  public void setUp() throws Exception {
+    RAMDirectory dir = new RAMDirectory();
+    IndexWriter w = new IndexWriter(dir, new WhitespaceAnalyzer(), true,
+            MaxFieldLength.LIMITED);
+    Document doc;
+    for (int i = 0; i < NUM_DOCS; i++) {
+      doc = new Document();
+      doc.add(new Field("id", i + "", Field.Store.YES, Field.Index.NOT_ANALYZED));
+      doc.add(new Field("f", i + " " + i, Field.Store.YES, Field.Index.ANALYZED));
+      w.addDocument(doc);
+    }
+    w.close();
+    input = IndexReader.open(dir, false);
+    // delete the last doc
+    input.deleteDocument(input.maxDoc() - 1);
+    input = input.reopen(true);
+  }
+  
+  /**
+   * Test round-robin splitting.
+   */
+  public void testSplitRR() throws Exception {
+    MultiPassIndexSplitter splitter = new MultiPassIndexSplitter();
+    Directory[] dirs = new Directory[]{
+            new RAMDirectory(),
+            new RAMDirectory(),
+            new RAMDirectory()
+    };
+    splitter.split(input, dirs, false);
+    IndexReader ir;
+    ir = IndexReader.open(dirs[0], true);
+    assertTrue(ir.numDocs() - NUM_DOCS / 3 <= 1); // rounding error
+    Document doc = ir.document(0);
+    assertEquals("0", doc.get("id"));
+    Term t;
+    TermEnum te;
+    t = new Term("id", "1");
+    te = ir.terms(t);
+    assertNotSame(t, te.term());
+    ir.close();
+    ir = IndexReader.open(dirs[1], true);
+    assertTrue(ir.numDocs() - NUM_DOCS / 3 <= 1);
+    doc = ir.document(0);
+    assertEquals("1", doc.get("id"));
+    t = new Term("id", "0");
+    te = ir.terms(t);
+    assertNotSame(t, te.term());
+    ir.close();
+    ir = IndexReader.open(dirs[2], true);
+    assertTrue(ir.numDocs() - NUM_DOCS / 3 <= 1);
+    doc = ir.document(0);
+    assertEquals("2", doc.get("id"));
+    t = new Term("id", "1");
+    te = ir.terms(t);
+    assertNotSame(t, te.term());
+    t = new Term("id", "0");
+    te = ir.terms(t);
+    assertNotSame(t, te.term());    
+  }
+  
+  /**
+   * Test sequential splitting.
+   */
+  public void testSplitSeq() throws Exception {
+    MultiPassIndexSplitter splitter = new MultiPassIndexSplitter();
+    Directory[] dirs = new Directory[]{
+            new RAMDirectory(),
+            new RAMDirectory(),
+            new RAMDirectory()
+    };
+    splitter.split(input, dirs, true);
+    IndexReader ir;
+    ir = IndexReader.open(dirs[0], true);
+    assertTrue(ir.numDocs() - NUM_DOCS / 3 <= 1);
+    Document doc = ir.document(0);
+    assertEquals("0", doc.get("id"));
+    int start = ir.numDocs();
+    ir.close();
+    ir = IndexReader.open(dirs[1], true);
+    assertTrue(ir.numDocs() - NUM_DOCS / 3 <= 1);
+    doc = ir.document(0);
+    assertEquals(start + "", doc.get("id"));
+    start += ir.numDocs();
+    ir.close();
+    ir = IndexReader.open(dirs[2], true);
+    assertTrue(ir.numDocs() - NUM_DOCS / 3 <= 1);
+    doc = ir.document(0);
+    assertEquals(start + "", doc.get("id"));
+    // make sure the deleted doc is not here
+    Term t;
+    TermEnum te;
+    t = new Term("id", (NUM_DOCS - 1) + "");
+    te = ir.terms(t);
+    assertNotSame(t, te.term());    
+  }
+}