From 5a7c9939cbe115c0d12d9cfe8bf9f3b3d11ac69e Mon Sep 17 00:00:00 2001
From: tedyu <yuzhihong@gmail.com>
Date: Fri, 1 Jul 2016 09:43:39 -0700
Subject: [PATCH] HBASE-16157 The incorrect block cache count and size are
 caused by removing duplicate block key in the LruBlockCache (ChiaPing Tsai)

---
 .../hadoop/hbase/io/hfile/LruBlockCache.java  | 15 ++++++++-
 .../hbase/io/hfile/TestLruBlockCache.java     | 32 +++++++++++++++++++
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/LruBlockCache.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/LruBlockCache.java
index c380318c48a..8894dcd577a 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/LruBlockCache.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/LruBlockCache.java
@@ -511,7 +511,10 @@ public class LruBlockCache implements ResizableBlockCache, HeapSize {
    * @return the heap size of evicted block
    */
   protected long evictBlock(LruCachedBlock block, boolean evictedByEvictionProcess) {
-    map.remove(block.getCacheKey());
+    boolean found = map.remove(block.getCacheKey()) != null;
+    if (!found) {
+      return 0;
+    }
     updateSizeMetrics(block, true);
     long val = elements.decrementAndGet();
     if (LOG.isTraceEnabled()) {
@@ -543,6 +546,16 @@ public class LruBlockCache implements ResizableBlockCache, HeapSize {
     }
   }
 
+  @VisibleForTesting
+  boolean isEvictionInProgress() {
+    return evictionInProgress;
+  }
+
+  @VisibleForTesting
+  long getOverhead() {
+    return overhead;
+  }
+
   /**
    * Eviction method.
    */
diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestLruBlockCache.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestLruBlockCache.java
index d7f9aba6a91..4d0732eff80 100644
--- a/hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestLruBlockCache.java
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestLruBlockCache.java
@@ -44,7 +44,34 @@ import org.junit.experimental.categories.Category;
 @Category({IOTests.class, SmallTests.class})
 public class TestLruBlockCache {
 
+  @Test
+  public void testCurrentSize() throws Exception {
+    long maxSize = 100000;
+    int numBlocks = 9;
+    int testRuns = 10;
+    long blockSize = calculateBlockSizeDefault(maxSize, numBlocks);
+    assertTrue("calculateBlockSize appears broken.", blockSize * numBlocks <= maxSize);
 
+    LruBlockCache cache = new LruBlockCache(maxSize, blockSize);
+    EvictionThread evictionThread = cache.getEvictionThread();
+    assertTrue(evictionThread != null);
+    while (!evictionThread.isEnteringRun()) {
+      Thread.sleep(1);
+    }
+    int blockCount = 0;
+    String hfileName = "hfile";
+    for (int run = 0; run != testRuns; ++run) {
+      while (!cache.isEvictionInProgress()) {
+        CachedItem block = new CachedItem(hfileName, (int) blockSize, blockCount++);
+        boolean inMemory = Math.random() > 0.5;
+        cache.cacheBlock(block.cacheKey, block, inMemory, false);
+      }
+      assertEquals(true, cache.isEvictionInProgress());
+      cache.evictBlocksByHfileName(hfileName);
+      assertEquals(0, cache.getBlockCount());
+      assertEquals(cache.getOverhead(), cache.getCurrentSize());
+    }
+  }
   @Test
   public void testBackgroundEvictionThread() throws Exception {
     long maxSize = 100000;
@@ -785,6 +812,11 @@ public class TestLruBlockCache {
     BlockCacheKey cacheKey;
     int size;
 
+    CachedItem(String blockName, int size, int offset) {
+      this.cacheKey = new BlockCacheKey(blockName, offset);
+      this.size = size;
+    }
+
     CachedItem(String blockName, int size) {
       this.cacheKey = new BlockCacheKey(blockName, 0);
       this.size = size;