Merge pull request #385 from metamx/fix-local-cache-drift

fix local cache byte counting on object removal

server/src/main/java/io/druid/client/cache/ByteCountingLRUMap.java

@@ -24,6 +24,7 @@ import com.metamx.common.logger.Logger;
 import java.nio.ByteBuffer;
 import java.util.LinkedHashMap;
 import java.util.Map;
+import java.util.Set;
 
 /**
 */
@@ -74,8 +75,7 @@ class ByteCountingLRUMap extends LinkedHashMap<ByteBuffer, byte[]>
   public byte[] put(ByteBuffer key, byte[] value)
   {
     numBytes += key.remaining() + value.length;
-    byte[] retVal = super.put(key, value);
-    return retVal;
+    return super.put(key, value);
   }
 
   @Override
@@ -98,4 +98,31 @@ class ByteCountingLRUMap extends LinkedHashMap<ByteBuffer, byte[]>
     }
     return false;
   }
+
+  @Override
+  public byte[] remove(Object key)
+  {
+    byte[] value = super.remove(key);
+    if(value != null) {
+      numBytes -= ((ByteBuffer)key).remaining() + value.length;
+    }
+    return value;
+  }
+
+  /**
+   * We want keySet().iterator().remove() to account for object removal
+   * The underlying Map calls this.remove(key) so we do not need to override this
+   */
+  @Override
+  public Set<ByteBuffer> keySet()
+  {
+    return super.keySet();
+  }
+
+  @Override
+  public void clear()
+  {
+    numBytes = 0;
+    super.clear();
+  }
 }

server/src/test/java/io/druid/client/cache/ByteCountingLRUMapTest.java

@@ -24,6 +24,7 @@ import org.junit.Before;
 import org.junit.Test;
 
 import java.nio.ByteBuffer;
+import java.util.Iterator;
 
 /**
  */
@@ -65,6 +66,18 @@ public class ByteCountingLRUMapTest
     assertMapValues(2, 101, 2);
     Assert.assertEquals(ByteBuffer.wrap(eightyEightVal), ByteBuffer.wrap(map.get(tenKey)));
     Assert.assertEquals(oneByte, ByteBuffer.wrap(map.get(twoByte)));
+
+    Iterator<ByteBuffer> it = map.keySet().iterator();
+    while(it.hasNext()) {
+      ByteBuffer buf = it.next();
+      if(buf.remaining() == 10) {
+        it.remove();
+      }
+    }
+    assertMapValues(1, 3, 2);
+
+    map.remove(twoByte);
+    assertMapValues(0, 0, 2);
   }
 
   private void assertMapValues(final int size, final int numBytes, final int evictionCount)