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From sim...@apache.org
Subject svn commit: r953407 - in /lucene/dev/trunk/lucene: CHANGES.txt src/java/org/apache/lucene/search/ParallelMultiSearcher.java
Date Thu, 10 Jun 2010 17:27:54 GMT
Author: simonw
Date: Thu Jun 10 17:27:53 2010
New Revision: 953407

URL: http://svn.apache.org/viewvc?rev=953407&view=rev
Log:
LUCENE-2494: use CompletionService in ParallelMultiSearcher instead of simple polling

Modified:
    lucene/dev/trunk/lucene/CHANGES.txt
    lucene/dev/trunk/lucene/src/java/org/apache/lucene/search/ParallelMultiSearcher.java

Modified: lucene/dev/trunk/lucene/CHANGES.txt
URL: http://svn.apache.org/viewvc/lucene/dev/trunk/lucene/CHANGES.txt?rev=953407&r1=953406&r2=953407&view=diff
==============================================================================
--- lucene/dev/trunk/lucene/CHANGES.txt (original)
+++ lucene/dev/trunk/lucene/CHANGES.txt Thu Jun 10 17:27:53 2010
@@ -763,6 +763,8 @@ API Changes
    (Robert Muir)
 
 Optimizations
+ * LUCENE-2494: Use CompletionService in ParallelMultiSearcher instead of
+   simple polling for resutls. (Edward Drapkin, Simon Willnauer) 
 
  * LUCENE-2086: When resolving deleted terms, do so in term sort order
    for better performance (Bogdan Ghidireac via Mike McCandless)

Modified: lucene/dev/trunk/lucene/src/java/org/apache/lucene/search/ParallelMultiSearcher.java
URL: http://svn.apache.org/viewvc/lucene/dev/trunk/lucene/src/java/org/apache/lucene/search/ParallelMultiSearcher.java?rev=953407&r1=953406&r2=953407&view=diff
==============================================================================
--- lucene/dev/trunk/lucene/src/java/org/apache/lucene/search/ParallelMultiSearcher.java (original)
+++ lucene/dev/trunk/lucene/src/java/org/apache/lucene/search/ParallelMultiSearcher.java Thu
Jun 10 17:27:53 2010
@@ -18,16 +18,17 @@ package org.apache.lucene.search;
  */
 
 import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.HashMap;
-import java.util.List;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
 import java.util.Set;
 import java.util.concurrent.Callable;
+import java.util.concurrent.CompletionService;
 import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorCompletionService;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
-import java.util.concurrent.Future;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
 
@@ -67,18 +68,20 @@ public class ParallelMultiSearcher exten
    */
   @Override
   public int docFreq(final Term term) throws IOException {
-    @SuppressWarnings("unchecked") final Future<Integer>[] searchThreads = new Future[searchables.length];
-    for (int i = 0; i < searchables.length; i++) { // search each searchable
+    final ExecutionHelper<Integer> runner = new ExecutionHelper<Integer>(executor);
+    for(int i = 0; i < searchables.length; i++) {
       final Searchable searchable = searchables[i];
-      searchThreads[i] = executor.submit(new Callable<Integer>() {
+      runner.submit(new Callable<Integer>() {
         public Integer call() throws IOException {
           return Integer.valueOf(searchable.docFreq(term));
         }
       });
     }
-    final CountDocFreq func = new CountDocFreq();
-    foreach(func, Arrays.asList(searchThreads));
-    return func.docFreq;
+    int docFreq = 0;
+    for (Integer num : runner) {
+      docFreq += num.intValue();
+    }
+    return docFreq;
   }
 
   /**
@@ -90,20 +93,25 @@ public class ParallelMultiSearcher exten
   public TopDocs search(Weight weight, Filter filter, int nDocs) throws IOException {
     final HitQueue hq = new HitQueue(nDocs, false);
     final Lock lock = new ReentrantLock();
-    @SuppressWarnings("unchecked") final Future<TopDocs>[] searchThreads = new Future[searchables.length];
+    final ExecutionHelper<TopDocs> runner = new ExecutionHelper<TopDocs>(executor);
+    
     for (int i = 0; i < searchables.length; i++) { // search each searchable
-      searchThreads[i] = executor.submit(
+      runner.submit(
           new MultiSearcherCallableNoSort(lock, searchables[i], weight, filter, nDocs, hq,
i, starts));
     }
 
-    final CountTotalHits<TopDocs> func = new CountTotalHits<TopDocs>();
-    foreach(func, Arrays.asList(searchThreads));
+    int totalHits = 0;
+    float maxScore = Float.NEGATIVE_INFINITY;
+    for (final TopDocs topDocs : runner) {
+      totalHits += topDocs.totalHits;
+      maxScore = Math.max(maxScore, topDocs.getMaxScore());
+    }
 
     final ScoreDoc[] scoreDocs = new ScoreDoc[hq.size()];
     for (int i = hq.size() - 1; i >= 0; i--) // put docs in array
       scoreDocs[i] = hq.pop();
 
-    return new TopDocs(func.totalHits, scoreDocs, func.maxScore);
+    return new TopDocs(totalHits, scoreDocs, maxScore);
   }
 
   /**
@@ -117,20 +125,22 @@ public class ParallelMultiSearcher exten
 
     final FieldDocSortedHitQueue hq = new FieldDocSortedHitQueue(nDocs);
     final Lock lock = new ReentrantLock();
-    @SuppressWarnings("unchecked") final Future<TopFieldDocs>[] searchThreads = new
Future[searchables.length];
+    final ExecutionHelper<TopFieldDocs> runner = new ExecutionHelper<TopFieldDocs>(executor);
     for (int i = 0; i < searchables.length; i++) { // search each searchable
-      searchThreads[i] = executor.submit(
+      runner.submit(
           new MultiSearcherCallableWithSort(lock, searchables[i], weight, filter, nDocs,
hq, sort, i, starts));
     }
-
-    final CountTotalHits<TopFieldDocs> func = new CountTotalHits<TopFieldDocs>();
-    foreach(func, Arrays.asList(searchThreads));
-
+    int totalHits = 0;
+    float maxScore = Float.NEGATIVE_INFINITY;
+    for (final TopFieldDocs topFieldDocs : runner) {
+      totalHits += topFieldDocs.totalHits;
+      maxScore = Math.max(maxScore, topFieldDocs.getMaxScore());
+    }
     final ScoreDoc[] scoreDocs = new ScoreDoc[hq.size()];
     for (int i = hq.size() - 1; i >= 0; i--) // put docs in array
       scoreDocs[i] = hq.pop();
 
-    return new TopFieldDocs(func.totalHits, scoreDocs, hq.getFields(), func.maxScore);
+    return new TopFieldDocs(totalHits, scoreDocs, hq.getFields(), maxScore);
   }
 
   /** Lower-level search API.
@@ -192,13 +202,17 @@ public class ParallelMultiSearcher exten
   HashMap<Term, Integer> createDocFrequencyMap(Set<Term> terms) throws IOException
{
     final Term[] allTermsArray = terms.toArray(new Term[terms.size()]);
     final int[] aggregatedDocFreqs = new int[terms.size()];
-    final ArrayList<Future<int[]>> searchThreads = new ArrayList<Future<int[]>>(searchables.length);
+    final ExecutionHelper<int[]> runner = new ExecutionHelper<int[]>(executor);
     for (Searchable searchable : searchables) {
-      final Future<int[]> future = executor.submit(
+      runner.submit(
           new DocumentFrequencyCallable(searchable, allTermsArray));
-      searchThreads.add(future);
     }
-    foreach(new AggregateDocFrequency(aggregatedDocFreqs), searchThreads);
+    final int docFreqLen = aggregatedDocFreqs.length;
+    for (final int[] docFreqs : runner) {
+      for(int i=0; i < docFreqLen; i++){
+        aggregatedDocFreqs[i] += docFreqs[i];
+      }
+    }
 
     final HashMap<Term,Integer> dfMap = new HashMap<Term,Integer>();
     for(int i=0; i<allTermsArray.length; i++) {
@@ -206,77 +220,7 @@ public class ParallelMultiSearcher exten
     }
     return dfMap;
   }
-  
-  /*
-   * apply the function to each element of the list. This method encapsulates the logic how

-   * to wait for concurrently executed searchables.  
-   */
-  private <T> void foreach(Function<T> func, List<Future<T>> list)
throws IOException{
-    for (Future<T> future : list) {
-      try{
-        func.apply(future.get());
-      } catch (ExecutionException e) {
-        final Throwable throwable = e.getCause();
-        if (throwable instanceof IOException)
-          throw (IOException) e.getCause();
-        throw new RuntimeException(throwable);
-      } catch (InterruptedException ie) {
-        throw new ThreadInterruptedException(ie);
-      }
-    }
-  }
 
-  // Both functions could be reduced to Int as other values of TopDocs
-  // are not needed. Using sep. functions is more self documenting.
-  /**
-   * A function with one argument
-   * @param <T> the argument type
-   */
-  private static interface Function<T> {
-    abstract void apply(T t);
-  }
-
-  /**
-   * Counts the total number of hits for all {@link TopDocs} instances
-   * provided. 
-   */
-  private static final class CountTotalHits<T extends TopDocs> implements Function<T>
{
-    int totalHits = 0;
-    float maxScore = Float.NEGATIVE_INFINITY;
-    
-    public void apply(T t) {
-      totalHits += t.totalHits;
-      maxScore = Math.max(maxScore, t.getMaxScore());
-    }
-  }
-  
-  /**
-   * Accumulates the document frequency for a term.
-   */
-  private static final class CountDocFreq implements Function<Integer>{
-    int docFreq = 0;
-    
-    public void apply(Integer t) {
-      docFreq += t.intValue();
-    }
-  }
-  
-  /**
-   * Aggregates the document frequencies from multiple searchers 
-   */
-  private static final class AggregateDocFrequency implements Function<int[]>{
-    final int[] aggregatedDocFreqs;
-    
-    public AggregateDocFrequency(int[] aggregatedDocFreqs){
-      this.aggregatedDocFreqs = aggregatedDocFreqs;
-    }
-    
-    public void apply(final int[] docFreqs) {
-      for(int i=0; i<aggregatedDocFreqs.length; i++){
-        aggregatedDocFreqs[i] += docFreqs[i];
-      }
-    }
-  }
   
   /**
    * A {@link Callable} to retrieve the document frequencies for a Term array  
@@ -294,4 +238,53 @@ public class ParallelMultiSearcher exten
       return searchable.docFreqs(terms);
     }
   }
+  
+  /**
+   * A helper class that wraps a {@link CompletionService} and provides an
+   * iterable interface to the completed {@link Callable} instances.
+   * 
+   * @param <T>
+   *          the type of the {@link Callable} return value
+   */
+  private static final class ExecutionHelper<T> implements Iterator<T>, Iterable<T>
{
+    private final CompletionService<T> service;
+    private int numTasks;
+
+    ExecutionHelper(final Executor executor) {
+      this.service = new ExecutorCompletionService<T>(executor);
+    }
+
+    public boolean hasNext() {
+      return numTasks > 0;
+    }
+
+    public void submit(Callable<T> task) {
+      this.service.submit(task);
+      ++numTasks;
+    }
+
+    public T next() {
+     if(!this.hasNext())
+       throw new NoSuchElementException();
+      try {
+        return service.take().get();
+      } catch (InterruptedException e) {
+        throw new ThreadInterruptedException(e);
+      } catch (ExecutionException e) {
+        throw new RuntimeException(e);
+      } finally {
+        --numTasks;
+      }
+    }
+
+    public void remove() {
+      throw new UnsupportedOperationException();
+    }
+
+    public Iterator<T> iterator() {
+      // use the shortcut here - this is only used in a privat context
+      return this;
+    }
+
+  }
 }



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