From ed423e2deb82f4741744fc523b671eea075db195 Mon Sep 17 00:00:00 2001
From: Zhihong Yu <tedyu@apache.org>
Date: Tue, 11 Feb 2014 03:58:42 +0000
Subject: [PATCH] HBASE-10487 Avoid allocating new KeyValue and according
 bytes-copying for appended kvs which don't have existing values (Honghua)

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1566981 13f79535-47bb-0310-9956-ffa450edef68
---
 .../hadoop/hbase/regionserver/HRegion.java    | 36 ++++++++-----------
 .../hbase/client/TestFromClientSide.java      |  7 +++-
 2 files changed, 20 insertions(+), 23 deletions(-)

diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java
index ecb49969120..59dcf3ce0af 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java
@@ -5010,30 +5010,22 @@ public class HRegion implements HeapSize { // , Writable{
                     newKV.getTagsOffset(), oldKv.getTagsLength());
                 System.arraycopy(kv.getTagsArray(), kv.getTagsOffset(), newKV.getTagsArray(),
                     newKV.getTagsOffset() + oldKv.getTagsLength(), kv.getTagsLength());
+                // copy in row, family, and qualifier
+                System.arraycopy(kv.getRowArray(), kv.getRowOffset(),
+                    newKV.getRowArray(), newKV.getRowOffset(), kv.getRowLength());
+                System.arraycopy(kv.getFamilyArray(), kv.getFamilyOffset(),
+                    newKV.getFamilyArray(), newKV.getFamilyOffset(),
+                    kv.getFamilyLength());
+                System.arraycopy(kv.getQualifierArray(), kv.getQualifierOffset(),
+                    newKV.getQualifierArray(), newKV.getQualifierOffset(),
+                    kv.getQualifierLength());
                 idx++;
               } else {
-                // allocate an empty kv once
-                newKV = new KeyValue(row.length, kv.getFamilyLength(),
-                    kv.getQualifierLength(), now, KeyValue.Type.Put,
-                    kv.getValueLength(), kv.getTagsLength());
-                // copy in the value
-                System.arraycopy(kv.getValueArray(), kv.getValueOffset(),
-                    newKV.getValueArray(), newKV.getValueOffset(),
-                    kv.getValueLength());
-                // copy in tags
-                System.arraycopy(kv.getTagsArray(), kv.getTagsOffset(), newKV.getTagsArray(),
-                    newKV.getTagsOffset(), kv.getTagsLength());
-              }
-              // copy in row, family, and qualifier
-              System.arraycopy(kv.getRowArray(), kv.getRowOffset(),
-                  newKV.getRowArray(), newKV.getRowOffset(), kv.getRowLength());
-              System.arraycopy(kv.getFamilyArray(), kv.getFamilyOffset(),
-                  newKV.getFamilyArray(), newKV.getFamilyOffset(),
-                  kv.getFamilyLength());
-              System.arraycopy(kv.getQualifierArray(), kv.getQualifierOffset(),
-                  newKV.getQualifierArray(), newKV.getQualifierOffset(),
-                  kv.getQualifierLength());
-
+                newKV = kv;
+                // Append's KeyValue.Type==Put and ts==HConstants.LATEST_TIMESTAMP,
+                // so only need to update the timestamp to 'now'
+                newKV.updateLatestStamp(Bytes.toBytes(now));
+             }
               newKV.setMvccVersion(w.getWriteNumber());
               // Give coprocessors a chance to update the new cell
               if (coprocessorHost != null) {
diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestFromClientSide.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestFromClientSide.java
index 2d2969e8fa5..bb386727260 100644
--- a/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestFromClientSide.java
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestFromClientSide.java
@@ -4422,7 +4422,7 @@ public class TestFromClientSide {
     byte[] v1 = Bytes.toBytes("42");
     byte[] v2 = Bytes.toBytes("23");
     byte [][] QUALIFIERS = new byte [][] {
-        Bytes.toBytes("b"), Bytes.toBytes("a")
+        Bytes.toBytes("b"), Bytes.toBytes("a"), Bytes.toBytes("c")
     };
     Append a = new Append(ROW);
     a.add(FAMILY, QUALIFIERS[0], v1);
@@ -4433,9 +4433,14 @@ public class TestFromClientSide {
     a = new Append(ROW);
     a.add(FAMILY, QUALIFIERS[0], v2);
     a.add(FAMILY, QUALIFIERS[1], v1);
+    a.add(FAMILY, QUALIFIERS[2], v2);
     Result r = t.append(a);
     assertEquals(0, Bytes.compareTo(Bytes.add(v1,v2), r.getValue(FAMILY, QUALIFIERS[0])));
     assertEquals(0, Bytes.compareTo(Bytes.add(v2,v1), r.getValue(FAMILY, QUALIFIERS[1])));
+    // QUALIFIERS[2] previously not exist, verify both value and timestamp are correct
+    assertEquals(0, Bytes.compareTo(v2, r.getValue(FAMILY, QUALIFIERS[2])));
+    assertEquals(r.getColumnLatest(FAMILY, QUALIFIERS[0]).getTimestamp(),
+        r.getColumnLatest(FAMILY, QUALIFIERS[2]).getTimestamp());
   }
 
   @Test