LUCENE-4576: Remove CachingWrapperFilter recacheDeletes boolean

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1414474 13f79535-47bb-0310-9956-ffa450edef68

lucene/CHANGES.txt

@@ -54,6 +54,11 @@ Changes in backwards compatibility policy
     abstract.
     (Shai Erera, Gilad Barkai)
 
+* LUCENE-4576: Remove CachingWrapperFilter(Filter, boolean). This recacheDeletes
+  option gave less than 1% speedup at the expense of cache churn (filters were
+  invalidated on reopen if even a single delete was posted against the segment).
+  (Robert Muir)
+
 New Features
 
 * LUCENE-4226: New experimental StoredFieldsFormat that compresses chunks of

lucene/core/src/java/org/apache/lucene/search/CachingWrapperFilter.java

@@ -39,36 +39,12 @@ public class CachingWrapperFilter extends Filter {
   // level of the readers hierarchy it should be cached.
   private final Filter filter;
   private final Map<Object,DocIdSet> cache = Collections.synchronizedMap(new WeakHashMap<Object,DocIdSet>());
-  private final boolean recacheDeletes;
 
   /** Wraps another filter's result and caches it.
-   * Deletions are not cached and AND'd in on the fly, see
-   * {@link #CachingWrapperFilter(Filter,boolean)} for an explanation.
-   * This constructor is recommended for often changing indexes.
    * @param filter Filter to cache results of
-   * @see #CachingWrapperFilter(Filter,boolean)
    */
   public CachingWrapperFilter(Filter filter) {
-    this(filter, false);
-  }
-
-  /** Wraps another filter's result and caches it. If
-   * {@code recacheDeletes} is {@code true}, then new deletes (for example
-   * after {@link DirectoryReader#openIfChanged}) will cause the filter
-   * {@link DocIdSet} to be recached.
-   *
-   * <p>If your index changes seldom, it is recommended to use {@code recacheDeletes=true},
-   * as recaching will only occur when the index is reopened.
-   * For near-real-time indexes or indexes that are often
-   * reopened with (e.g., {@link DirectoryReader#openIfChanged} is used), you should
-   * pass {@code recacheDeletes=false}. This will cache the filter results omitting
-   * deletions and will AND them in while scoring.
-   * @param filter Filter to cache results of
-   * @param recacheDeletes if deletions on the underlying index should recache
-   */
-  public CachingWrapperFilter(Filter filter, boolean recacheDeletes) {
     this.filter = filter;
-    this.recacheDeletes = recacheDeletes;
   }
 
   /** Provide the DocIdSet to be cached, using the DocIdSet provided
@@ -104,54 +80,34 @@ public class CachingWrapperFilter extends Filter {
   @Override
   public DocIdSet getDocIdSet(AtomicReaderContext context, final Bits acceptDocs) throws IOException {
     final AtomicReader reader = context.reader();
-
-    // Only cache if incoming acceptDocs is == live docs;
-    // if Lucene passes in more interesting acceptDocs in
-    // the future (@UweSays: it already does when you chain FilteredQuery) we don't want to over-cache:
-    final Bits liveDocs = reader.getLiveDocs();
-    final boolean doCacheAcceptDocs = (recacheDeletes && acceptDocs == liveDocs);
-
-    final Object key;
-    final Bits cacheAcceptDocs;
-    if (doCacheAcceptDocs) {
-      assert acceptDocs == liveDocs;
-      key = reader.getCombinedCoreAndDeletesKey();
-      cacheAcceptDocs = acceptDocs;
-    } else {
-      key = reader.getCoreCacheKey();
-      cacheAcceptDocs = null;
-    }
+    final Object key = reader.getCoreCacheKey();
 
     DocIdSet docIdSet = cache.get(key);
     if (docIdSet != null) {
       hitCount++;
     } else {
       missCount++;
-      docIdSet = docIdSetToCache(filter.getDocIdSet(context, cacheAcceptDocs), reader);
+      docIdSet = docIdSetToCache(filter.getDocIdSet(context, null), reader);
       cache.put(key, docIdSet);
     }
 
-    if (doCacheAcceptDocs) {
-      return docIdSet;
-    } else {
     return BitsFilteredDocIdSet.wrap(docIdSet, acceptDocs);
   }
-  }
 
   @Override
   public String toString() {
-    return "CachingWrapperFilter("+filter+",recacheDeletes=" + recacheDeletes + ")";
+    return "CachingWrapperFilter("+filter+")";
   }
 
   @Override
   public boolean equals(Object o) {
     if (!(o instanceof CachingWrapperFilter)) return false;
     final CachingWrapperFilter other = (CachingWrapperFilter) o;
-    return this.filter.equals(other.filter) && this.recacheDeletes == other.recacheDeletes;
+    return this.filter.equals(other.filter);
   }
 
   @Override
   public int hashCode() {
-    return (filter.hashCode() ^ 0x1117BF25) + (recacheDeletes ? 0 : 1);
+    return (filter.hashCode() ^ 0x1117BF25);
   }
 }

lucene/core/src/test/org/apache/lucene/search/TestCachingWrapperFilter.java

@@ -189,8 +189,7 @@ public class TestCachingWrapperFilter extends LuceneTestCase {
 
     final Filter startFilter = new QueryWrapperFilter(new TermQuery(new Term("id", "1")));
 
-    // force cache to regenerate after deletions:
-    CachingWrapperFilter filter = new CachingWrapperFilter(startFilter, true);
+    CachingWrapperFilter filter = new CachingWrapperFilter(startFilter);
 
     docs = searcher.search(new MatchAllDocsQuery(), filter, 1);
 
@@ -231,9 +230,8 @@ public class TestCachingWrapperFilter extends LuceneTestCase {
     docs = searcher.search(new MatchAllDocsQuery(), filter, 1);
     assertEquals("[query + filter] Should *not* find a hit...", 0, docs.totalHits);
 
-    // cache miss, because we asked CWF to recache when
-    // deletes changed:
-    assertEquals(missCount+1, filter.missCount);
+    // cache hit
+    assertEquals(missCount, filter.missCount);
     docs = searcher.search(constantScore, 1);
     assertEquals("[just filter] Should *not* find a hit...", 0, docs.totalHits);