HIVE-2881 Remove redundant key comparing in SMBMapJoinOperator

(Navis via namit)



git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1308241 13f79535-47bb-0310-9956-ffa450edef68

ql/src/java/org/apache/hadoop/hive/ql/exec/SMBMapJoinOperator.java

@@ -318,10 +318,9 @@ private boolean allFetchOpDone() {
   }
 
   private List<Byte> joinOneGroup() throws HiveException {
-    int smallestPos = -1;
-    smallestPos = findSmallestKey();
+    int[] smallestPos = findSmallestKey();
     List<Byte> listOfNeedFetchNext = null;
-    if(smallestPos >= 0) {
+    if(smallestPos != null) {
       listOfNeedFetchNext = joinObject(smallestPos);
       if (listOfNeedFetchNext.size() > 0) {
         // listOfNeedFetchNext contains all tables that we have joined data in their
@@ -336,29 +335,23 @@ private List<Byte> joinOneGroup() throws HiveException {
     return listOfNeedFetchNext;
   }
 
-  private List<Byte> joinObject(int smallestPos) throws HiveException {
+  private List<Byte> joinObject(int[] smallestPos) throws HiveException {
     List<Byte> needFetchList = new ArrayList<Byte>();
-    ArrayList<Object> smallKey = keyWritables[smallestPos];
-    needFetchList.add((byte)smallestPos);
-    this.storage.put((byte) smallestPos, this.candidateStorage[smallestPos]);
-    for (Byte i : order) {
-      if ((byte) smallestPos == i) {
+    byte index = (byte) (smallestPos.length - 1);
+    for (; index >= 0; index--) {
+      if (smallestPos[index] > 0 || keyWritables[index] == null) {
+        putDummyOrEmpty(index);
         continue;
       }
-      ArrayList<Object> key = keyWritables[i];
-      if (key == null) {
-        putDummyOrEmpty(i);
-      } else {
-        int cmp = compareKeys(key, smallKey);
-        if (cmp == 0) {
-          this.storage.put((byte) i, this.candidateStorage[i]);
-          needFetchList.add(i);
-          continue;
-        } else {
-          putDummyOrEmpty(i);
-        }
+      storage.put(index, candidateStorage[index]);
+      needFetchList.add(index);
+      if (smallestPos[index] < 0) {
+        break;
       }
     }
+    for (index--; index >= 0; index--) {
+      putDummyOrEmpty(index);
+    }
     checkAndGenObject();
     for (Byte pos : needFetchList) {
       this.candidateStorage[pos].clear();
@@ -442,8 +435,8 @@ private void putDummyOrEmpty(Byte i) {
     }
   }
 
-  private int findSmallestKey() {
-    byte index = -1;
+  private int[] findSmallestKey() {
+    int[] result = new int[order.length];
     ArrayList<Object> smallestOne = null;
 
     for (byte i : order) {
@@ -453,17 +446,15 @@ private int findSmallestKey() {
       }
       if (smallestOne == null) {
         smallestOne = key;
-        index = i;
+        result[i] = -1;
         continue;
       }
-      int cmp = compareKeys(key, smallestOne);
-      if (cmp < 0) {
+      result[i] = compareKeys(key, smallestOne);
+      if (result[i] < 0) {
         smallestOne = key;
-        index = i;
-        continue;
       }
     }
-    return index;
+    return smallestOne == null ? null : result;
   }
 
   private boolean processKey(byte alias, ArrayList<Object> key)