Index: lucene/CHANGES.txt
===================================================================
--- lucene/CHANGES.txt	(revision 1057985)
+++ lucene/CHANGES.txt	(working copy)
@@ -308,6 +308,9 @@
   false EOF after seeking to EOF then seeking back to same block you
   were just in and then calling readBytes (Robert Muir, Mike McCandless)
 
+* LUCENE-2860: Fixed SegmentInfo.sizeInBytes to factor includeDocStores when it 
+  decides whether to return the cached computed size or not. (Shai Erera)
+
 New features
 
 * LUCENE-2128: Parallelized fetching document frequencies during weight
Index: lucene/src/test/org/apache/lucene/index/TestSegmentInfo.java
===================================================================
--- lucene/src/test/org/apache/lucene/index/TestSegmentInfo.java	(revision 0)
+++ lucene/src/test/org/apache/lucene/index/TestSegmentInfo.java	(revision 0)
@@ -0,0 +1,48 @@
+package org.apache.lucene.index;
+
+import org.apache.lucene.analysis.MockAnalyzer;
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.Field;
+import org.apache.lucene.document.Field.Index;
+import org.apache.lucene.document.Field.Store;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.util.LuceneTestCase;
+
+/**
+ * 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.
+ */
+
+public class TestSegmentInfo extends LuceneTestCase {
+
+  public void testSizeInBytesCache() throws Exception {
+    Directory dir = newDirectory();
+    IndexWriterConfig conf = newIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer());
+    IndexWriter writer = new IndexWriter(dir, conf);
+    Document doc = new Document();
+    doc.add(new Field("a", "value", Store.YES, Index.ANALYZED));
+    writer.addDocument(doc);
+    writer.close();
+    
+    SegmentInfos sis = new SegmentInfos();
+    sis.read(dir);
+    SegmentInfo si = sis.info(0);
+    long sizeInBytesNoStore = si.sizeInBytes(false);
+    long sizeInBytesWithStore = si.sizeInBytes(true);
+    assertTrue("sizeInBytesNoStore=" + sizeInBytesNoStore + " sizeInBytesWithStore=" + sizeInBytesWithStore, sizeInBytesWithStore > sizeInBytesNoStore);
+    dir.close();
+  }
+  
+}

Property changes on: lucene/src/test/org/apache/lucene/index/TestSegmentInfo.java
___________________________________________________________________
Added: svn:keywords
   + Date Author Id Revision HeadURL
Added: svn:eol-style
   + native

Index: lucene/src/java/org/apache/lucene/index/SegmentInfo.java
===================================================================
--- lucene/src/java/org/apache/lucene/index/SegmentInfo.java	(revision 1057985)
+++ lucene/src/java/org/apache/lucene/index/SegmentInfo.java	(working copy)
@@ -72,10 +72,11 @@
                                                   // and true for newly created merged segments (both
                                                   // compound and non compound).
   
-  private List<String> files;                             // cached list of files that this segment uses
+  private List<String> files;                     // cached list of files that this segment uses
                                                   // in the Directory
 
-  long sizeInBytes = -1;                          // total byte size of all of our files (computed on demand)
+  private long sizeInBytesNoStore = -1;           // total byte size of all but the store files (computed on demand)
+  private long sizeInBytesWithStore = -1;         // total byte size of all of our files (computed on demand)
 
   private int docStoreOffset;                     // if this segment shares stored fields & vectors, this
                                                   // offset is where in that file this segment's docs begin
@@ -265,25 +266,33 @@
     }
   }
 
-  /** Returns total size in bytes of all of files used by
-   *  this segment. */
+  /**
+   * Returns total size in bytes of all of files used by this segment (if
+   * {@code includeDocStores} is true), or the size of all files except the store
+   * files otherwise.
+   */
   public long sizeInBytes(boolean includeDocStores) throws IOException {
-    if (sizeInBytes == -1) {
-      List<String> files = files();
-      final int size = files.size();
-      sizeInBytes = 0;
-      for(int i=0;i<size;i++) {
-        final String fileName = files.get(i);
-        if (!includeDocStores && IndexFileNames.isDocStoreFile(fileName)) {
+    if (includeDocStores) {
+      if (sizeInBytesWithStore != -1) return sizeInBytesWithStore;
+      sizeInBytesWithStore = 0;
+      for (final String fileName : files()) {
+        // We don't count bytes used by a shared doc store against this segment
+        if (docStoreOffset == -1 || !IndexFileNames.isDocStoreFile(fileName)) {
+          sizeInBytesWithStore += dir.fileLength(fileName);
+        }
+      }
+      return sizeInBytesWithStore;
+    } else {
+      if (sizeInBytesNoStore != -1) return sizeInBytesNoStore;
+      sizeInBytesNoStore = 0;
+      for (final String fileName : files()) {
+        if (IndexFileNames.isDocStoreFile(fileName)) {
           continue;
         }
-        // We don't count bytes used by a shared doc store
-        // against this segment:
-        if (docStoreOffset == -1 || !IndexFileNames.isDocStoreFile(fileName))
-          sizeInBytes += dir.fileLength(fileName);
+        sizeInBytesNoStore += dir.fileLength(fileName);
       }
+      return sizeInBytesNoStore;
     }
-    return sizeInBytes;
   }
 
   public boolean getHasVectors() throws IOException {
@@ -708,7 +717,8 @@
    * files this segment has. */
   private void clearFiles() {
     files = null;
-    sizeInBytes = -1;
+    sizeInBytesNoStore = -1;
+    sizeInBytesWithStore = -1;
   }
 
   /** {@inheritDoc} */