Copy the imlementation of Lopt optimization and apply changes from CALCITE-6737

Author: kasakrisz

Diff for: ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/Bug.java

@@ -100,4 +100,9 @@ public final class Bug {
    * Whether <a href="https://issues.apache.org/jira/browse/CALCITE-6513">CALCITE-6513</a> is fixed.
    */
   public static final boolean CALCITE_6513_FIXED = false;
+
+  /**
+   * Whether <a href="https://issues.apache.org/jira/browse/CALCITE-6513">CALCITE-6737</a> is fixed.
+   */
+  public static final boolean CALCITE_6737_FIXED = false;
 }

Diff for: ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/HiveLoptJoinTree.java

@@ -0,0 +1,223 @@
+/*
+ * 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.hive.ql.optimizer.calcite.rules;
+
+import org.apache.calcite.rel.RelNode;
+import org.apache.calcite.rel.core.Join;
+import org.apache.hadoop.hive.ql.optimizer.calcite.Bug;
+import org.checkerframework.checker.initialization.qual.NotOnlyInitialized;
+import org.checkerframework.checker.initialization.qual.UnderInitialization;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+public class HiveLoptJoinTree {
+  //~ Instance fields --------------------------------------------------------
+
+  @NotOnlyInitialized
+  private final BinaryTree factorTree;
+  private final RelNode joinTree;
+  private final boolean removableSelfJoin;
+
+  //~ Constructors -----------------------------------------------------------
+
+  /**
+   * Creates a join-tree consisting of a single node.
+   *
+   * @param joinTree RelNode corresponding to the single node
+   * @param factorId factor id of the node
+   */
+  @SuppressWarnings("argument.type.incompatible")
+  public HiveLoptJoinTree(RelNode joinTree, int factorId) {
+    if (Bug.CALCITE_6737_FIXED) {
+      throw new IllegalStateException("This class is redundant when the fix for CALCITE-6737 is merged into Calcite. " +
+              "Remove it and use LoptOptimizeJoinRule instead of HiveLoptOptimizeJoinRule");
+    }
+
+    this.joinTree = joinTree;
+    this.factorTree = new Leaf(factorId, this);
+    this.removableSelfJoin = false;
+  }
+
+  /**
+   * Associates the factor ids with a join-tree.
+   *
+   * @param joinTree RelNodes corresponding to the join tree
+   * @param factorTree tree of the factor ids
+   * @param removableSelfJoin whether the join corresponds to a removable
+   * self-join
+   */
+  public HiveLoptJoinTree(
+          RelNode joinTree,
+          BinaryTree factorTree,
+          boolean removableSelfJoin) {
+    if (Bug.CALCITE_6737_FIXED) {
+      throw new IllegalStateException("This class is redundant when the fix for CALCITE-6737 is merged into Calcite. " +
+              "Remove it and use LoptOptimizeJoinRule instead of HiveLoptOptimizeJoinRule");
+    }
+
+    this.joinTree = joinTree;
+    this.factorTree = factorTree;
+    this.removableSelfJoin = removableSelfJoin;
+  }
+
+  /**
+   * Associates the factor ids with a join-tree given the factors corresponding
+   * to the left and right subtrees of the join.
+   *
+   * @param joinTree RelNodes corresponding to the join tree
+   * @param leftFactorTree tree of the factor ids for left subtree
+   * @param rightFactorTree tree of the factor ids for the right subtree
+   */
+  public HiveLoptJoinTree(
+          RelNode joinTree,
+          BinaryTree leftFactorTree,
+          BinaryTree rightFactorTree) {
+    this(joinTree, leftFactorTree, rightFactorTree, false);
+  }
+
+  /**
+   * Associates the factor ids with a join-tree given the factors corresponding
+   * to the left and right subtrees of the join. Also indicates whether the
+   * join is a removable self-join.
+   *
+   * @param joinTree RelNodes corresponding to the join tree
+   * @param leftFactorTree tree of the factor ids for left subtree
+   * @param rightFactorTree tree of the factor ids for the right subtree
+   * @param removableSelfJoin true if the join is a removable self-join
+   */
+  public HiveLoptJoinTree(
+          RelNode joinTree,
+          BinaryTree leftFactorTree,
+          BinaryTree rightFactorTree,
+          boolean removableSelfJoin) {
+    if (Bug.CALCITE_6737_FIXED) {
+      throw new IllegalStateException("This class is redundant when the fix for CALCITE-6737 is merged into Calcite. "
+              + "Remove it and use LoptOptimizeJoinRule instead of HiveLoptOptimizeJoinRule");
+    }
+
+    factorTree = new HiveLoptJoinTree.Node(leftFactorTree, rightFactorTree, this);
+    this.joinTree = joinTree;
+    this.removableSelfJoin = removableSelfJoin;
+  }
+
+  //~ Methods ----------------------------------------------------------------
+
+  public RelNode getJoinTree() {
+    return joinTree;
+  }
+
+  public HiveLoptJoinTree getLeft() {
+    final HiveLoptJoinTree.Node node = (HiveLoptJoinTree.Node) factorTree;
+    return new HiveLoptJoinTree(
+            ((Join) joinTree).getLeft(),
+            node.getLeft(),
+            node.getLeft().getParent().isRemovableSelfJoin());
+  }
+
+  public HiveLoptJoinTree getRight() {
+    final HiveLoptJoinTree.Node node = (HiveLoptJoinTree.Node) factorTree;
+    return new HiveLoptJoinTree(
+            ((Join) joinTree).getRight(),
+            node.getRight(),
+            node.getRight().getParent().isRemovableSelfJoin());
+  }
+
+  public BinaryTree getFactorTree() {
+    return factorTree;
+  }
+
+  public List<Integer> getTreeOrder() {
+    List<Integer> treeOrder = new ArrayList<>();
+    getTreeOrder(treeOrder);
+    return treeOrder;
+  }
+
+  public void getTreeOrder(List<Integer> treeOrder) {
+    factorTree.getTreeOrder(treeOrder);
+  }
+
+  public boolean isRemovableSelfJoin() {
+    return removableSelfJoin;
+  }
+
+  //~ Inner Classes ----------------------------------------------------------
+
+  /**
+   * Simple binary tree class that stores an id in the leaf nodes and keeps
+   * track of the parent HiveLoptJoinTree object associated with the binary tree.
+   */
+  protected abstract static class BinaryTree {
+    @NotOnlyInitialized
+    private final HiveLoptJoinTree parent;
+
+    protected BinaryTree(@UnderInitialization HiveLoptJoinTree parent) {
+      this.parent = parent;
+    }
+
+    public HiveLoptJoinTree getParent() {
+      return parent;
+    }
+
+    public abstract void getTreeOrder(List<Integer> treeOrder);
+  }
+
+  /** Binary tree node that has no children. */
+  protected static class Leaf extends BinaryTree {
+    private final int id;
+
+    public Leaf(int rootId, @UnderInitialization HiveLoptJoinTree parent) {
+      super(parent);
+      this.id = rootId;
+    }
+
+    /** Returns the id associated with a leaf node in a binary tree. */
+    public int getId() {
+      return id;
+    }
+
+    @Override public void getTreeOrder(List<Integer> treeOrder) {
+      treeOrder.add(id);
+    }
+  }
+
+  /** Binary tree node that has two children. */
+  protected static class Node extends BinaryTree {
+    private final BinaryTree left;
+    private final BinaryTree right;
+
+    public Node(BinaryTree left, BinaryTree right, @UnderInitialization HiveLoptJoinTree parent) {
+      super(parent);
+      this.left = Objects.requireNonNull(left, "left");
+      this.right = Objects.requireNonNull(right, "right");
+    }
+
+    public BinaryTree getLeft() {
+      return left;
+    }
+
+    public BinaryTree getRight() {
+      return right;
+    }
+
+    @Override public void getTreeOrder(List<Integer> treeOrder) {
+      left.getTreeOrder(treeOrder);
+      right.getTreeOrder(treeOrder);
+    }
+  }
+}