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https://issues.apache.org/jira/browse/HIVE-22962?focusedWorklogId=401682&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-401682
]
ASF GitHub Bot logged work on HIVE-22962:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 11/Mar/20 18:57
Start Date: 11/Mar/20 18:57
Worklog Time Spent: 10m
Work Description: vineetgarg02 commented on pull request #943: HIVE-22962
URL: https://github.com/apache/hive/pull/943#discussion_r391186386
##########
File path:
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/RelFieldTrimmer.java
##########
@@ -0,0 +1,1124 @@
+/*
+ * 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.linq4j.Ord;
+import org.apache.calcite.plan.RelOptCluster;
+import org.apache.calcite.plan.RelOptUtil;
+import org.apache.calcite.rel.RelCollation;
+import org.apache.calcite.rel.RelCollations;
+import org.apache.calcite.rel.RelFieldCollation;
+import org.apache.calcite.rel.RelNode;
+import org.apache.calcite.rel.core.Aggregate;
+import org.apache.calcite.rel.core.AggregateCall;
+import org.apache.calcite.rel.core.CorrelationId;
+import org.apache.calcite.rel.core.Filter;
+import org.apache.calcite.rel.core.Join;
+import org.apache.calcite.rel.core.JoinRelType;
+import org.apache.calcite.rel.core.Project;
+import org.apache.calcite.rel.core.SetOp;
+import org.apache.calcite.rel.core.Sort;
+import org.apache.calcite.rel.core.TableScan;
+import org.apache.calcite.rel.logical.LogicalTableFunctionScan;
+import org.apache.calcite.rel.logical.LogicalTableModify;
+import org.apache.calcite.rel.logical.LogicalValues;
+import org.apache.calcite.rel.metadata.RelMetadataQuery;
+import org.apache.calcite.rel.type.RelDataType;
+import org.apache.calcite.rel.type.RelDataTypeFactory;
+import org.apache.calcite.rel.type.RelDataTypeField;
+import org.apache.calcite.rel.type.RelDataTypeImpl;
+import org.apache.calcite.rex.RexBuilder;
+import org.apache.calcite.rex.RexCorrelVariable;
+import org.apache.calcite.rex.RexDynamicParam;
+import org.apache.calcite.rex.RexFieldAccess;
+import org.apache.calcite.rex.RexLiteral;
+import org.apache.calcite.rex.RexNode;
+import org.apache.calcite.rex.RexPermuteInputsShuttle;
+import org.apache.calcite.rex.RexUtil;
+import org.apache.calcite.rex.RexVisitor;
+import org.apache.calcite.sql.SqlExplainFormat;
+import org.apache.calcite.sql.SqlExplainLevel;
+import org.apache.calcite.sql2rel.CorrelationReferenceFinder;
+import org.apache.calcite.tools.RelBuilder;
+import org.apache.calcite.util.Bug;
+import org.apache.calcite.util.ImmutableBitSet;
+import org.apache.calcite.util.Pair;
+import org.apache.calcite.util.ReflectUtil;
+import org.apache.calcite.util.ReflectiveVisitor;
+import org.apache.calcite.util.Util;
+import org.apache.calcite.util.mapping.IntPair;
+import org.apache.calcite.util.mapping.Mapping;
+import org.apache.calcite.util.mapping.MappingType;
+import org.apache.calcite.util.mapping.Mappings;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Iterables;
+
+import java.math.BigDecimal;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Set;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This class comes from Calcite almost as-is. The only change concerns
+ * the dispatcher and the builder, so the trimmer is thread-safe and can
+ * be reused across different queries. Definition follows.
+ *
+ * <p>Transformer that walks over a tree of relational expressions, replacing
each
+ * {@link RelNode} with a 'slimmed down' relational expression that projects
+ * only the columns required by its consumer.
+ *
+ * <p>Uses multi-methods to fire the right rule for each type of relational
+ * expression. This allows the transformer to be extended without having to
+ * add a new method to RelNode, and without requiring a collection of rule
+ * classes scattered to the four winds.
+ */
+public class RelFieldTrimmer implements ReflectiveVisitor {
+ //~ Static fields/initializers ---------------------------------------------
+
+ private static final Logger LOG =
LoggerFactory.getLogger(RelFieldTrimmer.class);
+
+ protected static final ThreadLocal<RelBuilder> REL_BUILDER =
+ new ThreadLocal<>();
+
+ //~ Instance fields --------------------------------------------------------
+
+ protected final HiveReflectUtil.ClassMethodDispatcher<TrimResult, RelNode>
trimFieldsDispatcher;
+
+ //~ Constructors -----------------------------------------------------------
+
+ /**
+ * Creates a RelFieldTrimmer.
+ */
+ protected RelFieldTrimmer(boolean useLMFBasedDispatcher) {
+ if (useLMFBasedDispatcher) {
+ this.trimFieldsDispatcher =
+ HiveReflectUtil.createMethodDispatcher(
+ TrimResult.class,
+ this,
+ "trimFields",
+ RelNode.class,
+ ImmutableBitSet.class,
+ Set.class);
+ } else {
+ this.trimFieldsDispatcher =
Review comment:
Is this still around only for testing/benchmarking? If so a comment would be
helpful
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Issue Time Tracking
-------------------
Worklog Id: (was: 401682)
Time Spent: 20m (was: 10m)
> Reuse HiveRelFieldTrimmer instance across queries
> -------------------------------------------------
>
> Key: HIVE-22962
> URL: https://issues.apache.org/jira/browse/HIVE-22962
> Project: Hive
> Issue Type: Improvement
> Components: CBO
> Reporter: Jesus Camacho Rodriguez
> Assignee: Jesus Camacho Rodriguez
> Priority: Major
> Labels: pull-request-available
> Attachments: HIVE-22962.01.patch, HIVE-22962.02.patch,
> HIVE-22962.03.patch, HIVE-22962.04.patch, HIVE-22962.05.patch,
> HIVE-22962.06.patch, HIVE-22962.patch
>
> Time Spent: 20m
> Remaining Estimate: 0h
>
> Currently we create multiple {{HiveRelFieldTrimmer}} instances per query.
> {{HiveRelFieldTrimmer}} uses a method dispatcher that has a built-in caching
> mechanism: given a certain object, it stores the method that was called for
> the object class. However, by instantiating the trimmer multiple times per
> query and across queries, we create a new dispatcher with each instantiation,
> thus effectively removing the caching mechanism that is built within the
> dispatcher.
> This issue is to reutilize the same {{HiveRelFieldTrimmer}} instance within a
> single query and across queries.
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