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* 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.calcite.rel.rules;
import java.util.ArrayList;
import java.util.List;
import javax.annotation.Nullable;
import org.apache.calcite.plan.RelOptCluster;
import org.apache.calcite.plan.RelOptRule;
import org.apache.calcite.plan.RelOptRuleCall;
import org.apache.calcite.plan.RelOptUtil;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.core.Join;
import org.apache.calcite.rel.core.RelFactories;
import org.apache.calcite.rel.core.TableScan;
import org.apache.calcite.rel.logical.LogicalJoin;
import org.apache.calcite.rex.RexBuilder;
import org.apache.calcite.rex.RexNode;
import org.apache.calcite.rex.RexPermuteInputsShuttle;
import org.apache.calcite.rex.RexUtil;
import org.apache.calcite.tools.RelBuilder;
import org.apache.calcite.tools.RelBuilderFactory;
import org.apache.calcite.util.ImmutableBitSet;
import org.apache.calcite.util.mapping.Mappings;
import com.google.common.base.Predicate;
/**
* modified form org.apache.calcite.rel.rules.JoinPushThroughJoinRule.
* The goal is to move joins with sub-queries after joins with tables,
* so that pre-defined join with tables can be matched
*/
public class OLAPJoinPushThroughJoinRule extends RelOptRule {
/**
* Instance of the rule that works on logical joins only, and pushes to the
* right.
*/
public static final RelOptRule INSTANCE = new OLAPJoinPushThroughJoinRule("OLAPJoinPushThroughJoinRule", LogicalJoin.class, RelFactories.LOGICAL_BUILDER);
public OLAPJoinPushThroughJoinRule(String description, Class<? extends Join> clazz, RelBuilderFactory relBuilderFactory) {
super(operand(clazz,
operand(clazz, operand(RelNode.class, any()), operand(RelNode.class, null, new Predicate<RelNode>() {
@Override
public boolean apply(@Nullable RelNode input) {
return !(input instanceof TableScan);
}
}, any())),
operand(TableScan.class, any())), relBuilderFactory, description);
}
@Override
public void onMatch(RelOptRuleCall call) {
onMatchRight(call);
}
private void onMatchRight(RelOptRuleCall call) {
final Join topJoin = call.rel(0);
final Join bottomJoin = call.rel(1);
final RelNode relC = call.rel(4);
final RelNode relA = bottomJoin.getLeft();
final RelNode relB = bottomJoin.getRight();
final RelOptCluster cluster = topJoin.getCluster();
// Preconditions.checkState(relA == call.rel(2));
// Preconditions.checkState(relB == call.rel(3));
// topJoin
// / \
// bottomJoin C
// / \
// A B
final int aCount = relA.getRowType().getFieldCount();
final int bCount = relB.getRowType().getFieldCount();
final int cCount = relC.getRowType().getFieldCount();
final ImmutableBitSet bBitSet = ImmutableBitSet.range(aCount, aCount + bCount);
// becomes
//
// newTopJoin
// / \
// newBottomJoin B
// / \
// A C
// If either join is not inner, we cannot proceed.
// (Is this too strict?)
// if (topJoin.getJoinType() != JoinRelType.INNER || bottomJoin.getJoinType() != JoinRelType.INNER) {
// return;
// }
// Split the condition of topJoin into a conjunction. Each of the
// parts that does not use columns from B can be pushed down.
final List<RexNode> intersecting = new ArrayList<>();
final List<RexNode> nonIntersecting = new ArrayList<>();
split(topJoin.getCondition(), bBitSet, intersecting, nonIntersecting);
// If there's nothing to push down, it's not worth proceeding.
if (nonIntersecting.isEmpty()) {
return;
}
// Split the condition of bottomJoin into a conjunction. Each of the
// parts that use columns from B will need to be pulled up.
final List<RexNode> bottomIntersecting = new ArrayList<>();
final List<RexNode> bottomNonIntersecting = new ArrayList<>();
split(bottomJoin.getCondition(), bBitSet, bottomIntersecting, bottomNonIntersecting);
// target: | A | C |
// source: | A | B | C |
// final Mappings.TargetMapping bottomMapping = Mappings
// .createShiftMapping(aCount + bCount + cCount, 0, 0, aCount, aCount, aCount + bCount,
// cCount);
final Mappings.TargetMapping bottomMapping = Mappings.createShiftMapping(aCount + bCount + cCount, 0, 0, aCount, aCount + cCount, aCount, bCount, aCount, aCount + bCount, cCount);
final List<RexNode> newBottomList = new ArrayList<>();
new RexPermuteInputsShuttle(bottomMapping, relA, relC).visitList(nonIntersecting, newBottomList);
new RexPermuteInputsShuttle(bottomMapping, relA, relC).visitList(bottomNonIntersecting, newBottomList);
final RexBuilder rexBuilder = cluster.getRexBuilder();
RexNode newBottomCondition = RexUtil.composeConjunction(rexBuilder, newBottomList, false);
final Join newBottomJoin = bottomJoin.copy(bottomJoin.getTraitSet(), newBottomCondition, relA, relC, bottomJoin.getJoinType(), bottomJoin.isSemiJoinDone());
// target: | A | C | B |
// source: | A | B | C |
final Mappings.TargetMapping topMapping = Mappings.createShiftMapping(aCount + bCount + cCount, 0, 0, aCount, aCount + cCount, aCount, bCount, aCount, aCount + bCount, cCount);
final List<RexNode> newTopList = new ArrayList<>();
new RexPermuteInputsShuttle(topMapping, newBottomJoin, relB).visitList(intersecting, newTopList);
new RexPermuteInputsShuttle(topMapping, newBottomJoin, relB).visitList(bottomIntersecting, newTopList);
RexNode newTopCondition = RexUtil.composeConjunction(rexBuilder, newTopList, false);
@SuppressWarnings("SuspiciousNameCombination")
final Join newTopJoin = topJoin.copy(topJoin.getTraitSet(), newTopCondition, newBottomJoin, relB, topJoin.getJoinType(), topJoin.isSemiJoinDone());
assert !Mappings.isIdentity(topMapping);
final RelBuilder relBuilder = call.builder();
relBuilder.push(newTopJoin);
relBuilder.project(relBuilder.fields(topMapping));
call.transformTo(relBuilder.build());
}
/**
* Splits a condition into conjunctions that do or do not intersect with
* a given bit set.
*/
static void split(RexNode condition, ImmutableBitSet bitSet, List<RexNode> intersecting, List<RexNode> nonIntersecting) {
for (RexNode node : RelOptUtil.conjunctions(condition)) {
ImmutableBitSet inputBitSet = RelOptUtil.InputFinder.bits(node);
if (bitSet.intersects(inputBitSet)) {
intersecting.add(node);
} else {
nonIntersecting.add(node);
}
}
}
}