HBASE-13448 New Cell implementation with cached component offsets/lengths.

hbase-common/src/main/java/org/apache/hadoop/hbase/KeyValue.java

@@ -147,6 +147,8 @@ public class KeyValue implements Cell, HeapSize, Cloneable, SettableSequenceId,
     Bytes.SIZEOF_INT /*keylength*/ +
     Bytes.SIZEOF_INT /*valuelength*/;
 
+  public static final int ROW_KEY_OFFSET = ROW_OFFSET + ROW_LENGTH_SIZE;
+
   // Size of the length ints in a KeyValue datastructure.
   public static final int KEYVALUE_INFRASTRUCTURE_SIZE = ROW_OFFSET;
 
@@ -1328,7 +1330,7 @@ public class KeyValue implements Cell, HeapSize, Cloneable, SettableSequenceId,
    */
   @Override
   public int getRowOffset() {
-    return getKeyOffset() + Bytes.SIZEOF_SHORT;
+    return this.offset + ROW_KEY_OFFSET;
   }
 
   /**
@@ -1359,7 +1361,7 @@ public class KeyValue implements Cell, HeapSize, Cloneable, SettableSequenceId,
    * @return Family offset
    */
   private int getFamilyOffset(int rlength) {
-    return this.offset + ROW_OFFSET + Bytes.SIZEOF_SHORT + rlength + Bytes.SIZEOF_BYTE;
+    return this.offset + ROW_KEY_OFFSET + rlength + Bytes.SIZEOF_BYTE;
   }
 
   /**

hbase-server/src/main/java/org/apache/hadoop/hbase/SizeCachedKeyValue.java

@@ -0,0 +1,67 @@
+/**
+ * Copyright The Apache Software Foundation
+ *
+ * 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.
+ */
+package org.apache.hadoop.hbase;
+
+import org.apache.hadoop.hbase.classification.InterfaceAudience;
+import org.apache.hadoop.hbase.util.Bytes;
+
+/**
+ * This class is an extension to KeyValue where rowLen and keyLen are cached.
+ * Parsing the backing byte[] every time to get these values will affect the performance.
+ * In read path, we tend to read these values many times in Comparator, SQM etc.
+ * Note: Please do not use these objects in write path as it will increase the heap space usage.
+ * See https://issues.apache.org/jira/browse/HBASE-13448
+ */
+@InterfaceAudience.Private
+public class SizeCachedKeyValue extends KeyValue {
+
+  private static final int HEAP_SIZE_OVERHEAD = Bytes.SIZEOF_SHORT + Bytes.SIZEOF_INT;
+
+  private short rowLen;
+  private int keyLen;
+
+  public SizeCachedKeyValue(byte[] bytes, int offset, int length) {
+    super(bytes, offset, length);
+    // We will read all these cached values at least once. Initialize now itself so that we can
+    // avoid uninitialized checks with every time call
+    rowLen = super.getRowLength();
+    keyLen = super.getKeyLength();
+  }
+
+  @Override
+  public short getRowLength() {
+    return rowLen;
+  }
+
+  @Override
+  public int getKeyLength() {
+    return this.keyLen;
+  }
+
+  @Override
+  public long heapSize() {
+    return super.heapSize() + HEAP_SIZE_OVERHEAD;
+  }
+
+  @Override
+  public long heapSizeWithoutTags() {
+    return super.heapSizeWithoutTags() + HEAP_SIZE_OVERHEAD;
+  }
+}

hbase-server/src/main/java/org/apache/hadoop/hbase/SizeCachedNoTagsKeyValue.java

@@ -0,0 +1,45 @@
+/**
+ * Copyright The Apache Software Foundation
+ *
+ * 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.
+ */
+package org.apache.hadoop.hbase;
+
+import org.apache.hadoop.hbase.classification.InterfaceAudience;
+
+/**
+ * This class is an extension to ContentSizeCachedKeyValue where there are no tags in Cell.
+ * Note: Please do not use these objects in write path as it will increase the heap space usage.
+ * See https://issues.apache.org/jira/browse/HBASE-13448
+ */
+@InterfaceAudience.Private
+public class SizeCachedNoTagsKeyValue extends SizeCachedKeyValue {
+
+  public SizeCachedNoTagsKeyValue(byte[] bytes, int offset, int length) {
+    super(bytes, offset, length);
+  }
+
+  @Override
+  public int getTagsLength() {
+    return 0;
+  }
+
+  @Override
+  public long heapSizeWithoutTags() {
+    return super.heapSize();
+  }
+}

hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/HFileReaderImpl.java

@@ -35,10 +35,11 @@ import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hbase.Cell;
 import org.apache.hadoop.hbase.CellComparator;
 import org.apache.hadoop.hbase.CellUtil;
+import org.apache.hadoop.hbase.SizeCachedKeyValue;
+import org.apache.hadoop.hbase.SizeCachedNoTagsKeyValue;
 import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.KeyValue;
 import org.apache.hadoop.hbase.KeyValueUtil;
-import org.apache.hadoop.hbase.NoTagsKeyValue;
 import org.apache.hadoop.hbase.fs.HFileSystem;
 import org.apache.hadoop.hbase.io.FSDataInputStreamWrapper;
 import org.apache.hadoop.hbase.io.compress.Compression;
@@ -827,22 +828,19 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
       if (!isSeeked())
         return null;
 
-      if(currTagsLen > 0) {
-        KeyValue ret = new KeyValue(blockBuffer.array(), blockBuffer.arrayOffset()
+      KeyValue ret;
+      if (currTagsLen > 0) {
+        ret = new SizeCachedKeyValue(blockBuffer.array(), blockBuffer.arrayOffset()
             + blockBuffer.position(), getCellBufSize());
-        if (this.reader.shouldIncludeMemstoreTS()) {
-          ret.setSequenceId(currMemstoreTS);
-        }
-        return ret;
       } else {
-        NoTagsKeyValue ret = new NoTagsKeyValue(blockBuffer.array(),
-            blockBuffer.arrayOffset() + blockBuffer.position(), getCellBufSize());
+        ret = new SizeCachedNoTagsKeyValue(blockBuffer.array(), blockBuffer.arrayOffset()
+            + blockBuffer.position(), getCellBufSize());
+      }
       if (this.reader.shouldIncludeMemstoreTS()) {
         ret.setSequenceId(currMemstoreTS);
       }
       return ret;
     }
-    }
 
     @Override
     public ByteBuffer getKey() {