Merge pull request #1299 from chrisdennis/issue-1291

Fixes #1291 : Ensure single element chains are moved correctly during compaction

clustered/server/src/main/java/org/ehcache/clustered/server/offheap/OffHeapChainMap.java

@@ -53,8 +53,12 @@ public OffHeapChainMap(PageSource source, Portability<? super K> keyPortability,
       public void evicting(Callable<Map.Entry<K, InternalChain>> callable) {
         try {
           Map.Entry<K, InternalChain> entry = callable.call();
-          if (evictionListener != null) {
-            evictionListener.onEviction(entry.getKey());
+          try {
+            if (evictionListener != null) {
+              evictionListener.onEviction(entry.getKey());
+            }
+          } finally {
+            entry.getValue().close();
           }
         } catch (Exception e) {
           throw new AssertionError(e);

clustered/server/src/main/java/org/ehcache/clustered/server/offheap/OffHeapChainStorageEngine.java

@@ -538,6 +538,10 @@ public boolean moved(long from, long to) {
           return false;
         } else {
           long tail = storage.readLong(to + CHAIN_HEADER_TAIL_OFFSET);
+          if (tail == from + CHAIN_HEADER_SIZE) {
+            tail = to + CHAIN_HEADER_SIZE;
+            storage.writeLong(to + CHAIN_HEADER_TAIL_OFFSET, tail);
+          }
           storage.writeLong(tail + ELEMENT_HEADER_NEXT_OFFSET, to);
           for (AttachedInternalChain activeChain : activeChains) {
             activeChain.moved(from, to);

clustered/server/src/test/java/org/ehcache/clustered/server/offheap/OffHeapServerStoreTest.java

@@ -16,6 +16,7 @@
 package org.ehcache.clustered.server.offheap;
 
 import java.nio.ByteBuffer;
+import java.util.Random;
 
 import org.ehcache.clustered.common.internal.store.Chain;
 import org.ehcache.clustered.common.internal.store.Element;
@@ -30,6 +31,7 @@
 import org.terracotta.offheapstore.buffersource.OffHeapBufferSource;
 import org.terracotta.offheapstore.exceptions.OversizeMappingException;
 import org.terracotta.offheapstore.paging.UnlimitedPageSource;
+import org.terracotta.offheapstore.paging.UpfrontAllocatingPageSource;
 
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.core.Is.is;
@@ -39,6 +41,7 @@
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.when;
+import static org.terracotta.offheapstore.util.MemoryUnit.MEGABYTES;
 
 public class OffHeapServerStoreTest extends ServerStoreTest {
 
@@ -161,4 +164,33 @@ public Object answer(InvocationOnMock invocation) throws Throwable {
     assertThat(payload.remaining(), is(8));
   }
 
+  @Test
+  public void testCrossSegmentShrinking() {
+    long seed = System.nanoTime();
+    Random random = new Random(seed);
+    try {
+      OffHeapServerStore store = new OffHeapServerStore(new UpfrontAllocatingPageSource(new OffHeapBufferSource(), MEGABYTES.toBytes(1L), MEGABYTES.toBytes(1)), 16);
+
+      ByteBuffer smallValue = ByteBuffer.allocate(1024);
+      for (int i = 0; i < 10000; i++) {
+        try {
+          store.getAndAppend(random.nextInt(500), smallValue.duplicate());
+        } catch (OversizeMappingException e) {
+          //ignore
+        }
+      }
+
+      ByteBuffer largeValue = ByteBuffer.allocate(100 * 1024);
+      for (int i = 0; i < 10000; i++) {
+        try {
+          store.getAndAppend(random.nextInt(500), largeValue.duplicate());
+        } catch (OversizeMappingException e) {
+          //ignore
+        }
+      }
+    } catch (Throwable t) {
+      throw (AssertionError) new AssertionError("Failed with seed " + seed).initCause(t);
+    }
+  }
+
 }