From b0232b4e403b7e175f876d3224a0a36654974416 Mon Sep 17 00:00:00 2001
From: Gian Merlino <gianmerlino@gmail.com>
Date: Thu, 12 Jan 2017 13:51:50 -0800
Subject: [PATCH] Replace our AggregateValuesRule with Calcite's. (#3845)

---
 .../calcite/planner/AggregateValuesRule.java  | 98 -------------------
 .../io/druid/sql/calcite/planner/Rules.java   |  1 +
 2 files changed, 1 insertion(+), 98 deletions(-)
 delete mode 100644 sql/src/main/java/io/druid/sql/calcite/planner/AggregateValuesRule.java

diff --git a/sql/src/main/java/io/druid/sql/calcite/planner/AggregateValuesRule.java b/sql/src/main/java/io/druid/sql/calcite/planner/AggregateValuesRule.java
deleted file mode 100644
index c80fb7ab7d2..00000000000
--- a/sql/src/main/java/io/druid/sql/calcite/planner/AggregateValuesRule.java
+++ /dev/null
@@ -1,98 +0,0 @@
-/*
- * Licensed to Metamarkets Group Inc. (Metamarkets) under one
- * or more contributor license agreements. See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership. Metamarkets 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 io.druid.sql.calcite.planner;
-
-import com.google.common.base.Predicates;
-import com.google.common.collect.ImmutableList;
-import org.apache.calcite.plan.RelOptRule;
-import org.apache.calcite.plan.RelOptRuleCall;
-import org.apache.calcite.rel.core.Aggregate;
-import org.apache.calcite.rel.core.AggregateCall;
-import org.apache.calcite.rel.core.Values;
-import org.apache.calcite.rel.logical.LogicalValues;
-import org.apache.calcite.rex.RexBuilder;
-import org.apache.calcite.rex.RexLiteral;
-
-import java.math.BigDecimal;
-
-/**
- * Rule that applies Aggregate to Values. Currently only applies to empty Values.
- *
- * This is still useful because PruneEmptyRules doesn't handle Aggregate, which is in turn because
- * Aggregate of empty relations need some special handling: a single row will be generated, where
- * each column's value depends on the specific aggregate calls (e.g. COUNT is 0, SUM is NULL).
- * Sample query where this matters: <code>SELECT COUNT(*) FROM s.foo WHERE 1 = 0</code>.
- *
- * Can be replaced by AggregateValuesRule in Calcite 1.11.0, when released.
- */
-public class AggregateValuesRule extends RelOptRule
-{
-  public static final AggregateValuesRule INSTANCE = new AggregateValuesRule();
-
-  private AggregateValuesRule()
-  {
-    super(
-        operand(Aggregate.class, null, Predicates.not(Aggregate.IS_NOT_GRAND_TOTAL),
-                operand(Values.class, null, Values.IS_EMPTY, none())
-        )
-    );
-  }
-
-  @Override
-  public void onMatch(RelOptRuleCall call)
-  {
-    final Aggregate aggregate = call.rel(0);
-    final Values values = call.rel(1);
-
-    final ImmutableList.Builder<RexLiteral> literals = ImmutableList.builder();
-
-    final RexBuilder rexBuilder = call.builder().getRexBuilder();
-    for (final AggregateCall aggregateCall : aggregate.getAggCallList()) {
-      switch (aggregateCall.getAggregation().getKind()) {
-        case COUNT:
-        case SUM0:
-          literals.add((RexLiteral) rexBuilder.makeLiteral(
-              BigDecimal.ZERO, aggregateCall.getType(), false));
-          break;
-
-        case MIN:
-        case MAX:
-        case SUM:
-          literals.add(rexBuilder.constantNull());
-          break;
-
-        default:
-          // Unknown what this aggregate call should do on empty Values. Bail out to be safe.
-          return;
-      }
-    }
-
-    call.transformTo(
-        LogicalValues.create(
-            values.getCluster(),
-            aggregate.getRowType(),
-            ImmutableList.of(literals.build())
-        )
-    );
-
-    // New plan is absolutely better than old plan.
-    call.getPlanner().setImportance(aggregate, 0.0);
-  }
-}
diff --git a/sql/src/main/java/io/druid/sql/calcite/planner/Rules.java b/sql/src/main/java/io/druid/sql/calcite/planner/Rules.java
index 2611061da61..1aba1f44791 100644
--- a/sql/src/main/java/io/druid/sql/calcite/planner/Rules.java
+++ b/sql/src/main/java/io/druid/sql/calcite/planner/Rules.java
@@ -35,6 +35,7 @@ import org.apache.calcite.rel.rules.AggregateProjectMergeRule;
 import org.apache.calcite.rel.rules.AggregateProjectPullUpConstantsRule;
 import org.apache.calcite.rel.rules.AggregateRemoveRule;
 import org.apache.calcite.rel.rules.AggregateStarTableRule;
+import org.apache.calcite.rel.rules.AggregateValuesRule;
 import org.apache.calcite.rel.rules.CalcRemoveRule;
 import org.apache.calcite.rel.rules.DateRangeRules;
 import org.apache.calcite.rel.rules.FilterAggregateTransposeRule;