[GitHub] [hive] amansinha100 commented on a change in pull request #3014: HIVE-25941: Long compilation time of complex query due to analysis fo…

[GitBox <gi...@apache.org>]

amansinha100 commented on a change in pull request #3014:
URL: https://github.com/apache/hive/pull/3014#discussion_r813594719



##########
File path: ql/src/java/org/apache/hadoop/hive/ql/metadata/MaterializedViewsCache.java
##########
@@ -205,4 +212,52 @@ HiveRelOptMaterialization get(String dbName, String viewName) {
   public boolean isEmpty() {
     return materializedViews.isEmpty();
   }
+
+
+  private static class ASTKey {
+    private final ASTNode root;
+
+    public ASTKey(ASTNode root) {
+      this.root = root;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+      if (this == o) return true;
+      if (o == null || getClass() != o.getClass()) return false;
+      ASTKey that = (ASTKey) o;
+      return equals(root, that.root);
+    }
+
+    private boolean equals(ASTNode astNode1, ASTNode astNode2) {
+      if (!(astNode1.getType() == astNode2.getType() &&
+              astNode1.getText().equals(astNode2.getText()) &&
+              astNode1.getChildCount() == astNode2.getChildCount())) {
+        return false;
+      }
+
+      for (int i = 0; i < astNode1.getChildCount(); ++i) {
+        if (!equals((ASTNode) astNode1.getChild(i), (ASTNode) astNode2.getChild(i))) {
+          return false;
+        }
+      }
+
+      return true;
+    }
+
+    @Override
+    public int hashCode() {
+      return hashcode(root);
+    }
+
+    private int hashcode(ASTNode node) {
+      int result = Objects.hash(node.getType(), node.getText());

Review comment:
       For complex view definitions, computing the hash code on entire string could be expensive.  Since the equals() method  is comparing the strings,  can we just use a substring here for the hash ?  e.g first 50 chars or something similar ?

##########
File path: ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/HiveMaterializedViewTextSubQueryRewriteShuttle.java
##########
@@ -0,0 +1,189 @@
+/*
+ * 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;
+
+import org.apache.calcite.plan.RelOptCluster;
+import org.apache.calcite.rel.RelNode;
+import org.apache.calcite.rex.RexNode;
+import org.apache.calcite.tools.RelBuilder;
+import org.apache.hadoop.hive.common.TableName;
+import org.apache.hadoop.hive.ql.lockmgr.HiveTxnManager;
+import org.apache.hadoop.hive.ql.metadata.Hive;
+import org.apache.hadoop.hive.ql.metadata.HiveException;
+import org.apache.hadoop.hive.ql.metadata.HiveRelOptMaterialization;
+import org.apache.hadoop.hive.ql.metadata.Table;
+import org.apache.hadoop.hive.ql.optimizer.calcite.reloperators.HiveFilter;
+import org.apache.hadoop.hive.ql.optimizer.calcite.reloperators.HiveProject;
+import org.apache.hadoop.hive.ql.optimizer.calcite.rules.views.HiveMaterializedViewUtils;
+import org.apache.hadoop.hive.ql.parse.ASTNode;
+import org.apache.hadoop.hive.ql.parse.CalcitePlanner;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.EnumSet;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.Stack;
+import java.util.function.Predicate;
+
+import static java.util.Collections.singletonList;
+import static java.util.Collections.unmodifiableMap;
+import static java.util.Collections.unmodifiableSet;
+import static org.apache.hadoop.hive.ql.metadata.HiveRelOptMaterialization.RewriteAlgorithm.NON_CALCITE;
+import static org.apache.hadoop.hive.ql.optimizer.calcite.rules.views.HiveMaterializedViewUtils.extractTable;
+
+/**
+ * Traverse the plan and tries to rewrite subtrees of the plan to materialized view scans.
+ *
+ * The rewrite depends on whether the subtree's corresponding AST match with any materialized view
+ * definitions AST.
+ */
+public class HiveMaterializedViewTextSubQueryRewriteShuttle extends HiveRelShuttleImpl {
+
+  private static final Logger LOG = LoggerFactory.getLogger(HiveMaterializedViewTextSubQueryRewriteShuttle.class);
+
+  private final Map<RelNode, ASTNode> subQueryMap;
+  private final ASTNode originalAST;
+  private final ASTNode expandedAST;
+  private final RelBuilder relBuilder;
+  private final Hive db;
+  private final Set<TableName> tablesUsedByOriginalPlan;
+  private final HiveTxnManager txnManager;
+
+  public HiveMaterializedViewTextSubQueryRewriteShuttle(

Review comment:
       The word 'Text' in the shuttle and in the rule names seems misleading now that the rewrite is being done at the AST level.  
   Also,  in HiveConf.java, there are the config options hive.materializedview.rewriting.sql.subquery and hive.materializedview.rewriting.sql .  The description there says 'text' which may create confusion.  At the same time AST is not user-friendly. Perhaps just saying 'syntax tree' instead of text might be ok.  Other suggestions ?




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